Merge pull request 'Added support for external calendars' (#14) from feature/external-calendars into main

Reviewed-on: #14

backend/Cargo.toml

@@ -22,6 +22,7 @@ hyper = { version = "1.0", features = ["full"] }
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 chrono = { version = "0.4", features = ["serde"] }
+chrono-tz = "0.8"
 uuid = { version = "1.0", features = ["v4", "serde"] }
 anyhow = "1.0"
 

backend/migrations/006_create_external_calendars_table.sql

@@ -0,0 +1,16 @@
+-- Create external_calendars table
+CREATE TABLE external_calendars (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    user_id INTEGER NOT NULL,
+    name TEXT NOT NULL,
+    url TEXT NOT NULL,
+    color TEXT NOT NULL DEFAULT '#4285f4',
+    is_visible BOOLEAN NOT NULL DEFAULT 1,
+    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+    updated_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+    last_fetched DATETIME,
+    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
+);
+
+-- Create index for performance
+CREATE INDEX idx_external_calendars_user_id ON external_calendars(user_id);

backend/migrations/007_create_external_calendar_cache_table.sql

@@ -0,0 +1,14 @@
+-- Create external calendar cache table for storing ICS data
+CREATE TABLE external_calendar_cache (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    external_calendar_id INTEGER NOT NULL,
+    ics_data TEXT NOT NULL,
+    cached_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    etag TEXT,
+    FOREIGN KEY (external_calendar_id) REFERENCES external_calendars(id) ON DELETE CASCADE,
+    UNIQUE(external_calendar_id)
+);
+
+-- Index for faster lookups
+CREATE INDEX idx_external_calendar_cache_calendar_id ON external_calendar_cache(external_calendar_id);
+CREATE INDEX idx_external_calendar_cache_cached_at ON external_calendar_cache(cached_at);

backend/src/auth.rs

@@ -112,6 +112,17 @@ impl AuthService {
         self.decode_token(token)
     }
 
+    /// Get user from token
+    pub async fn get_user_from_token(&self, token: &str) -> Result<crate::db::User, ApiError> {
+        let claims = self.verify_token(token)?;
+        
+        let user_repo = UserRepository::new(&self.db);
+        user_repo
+            .find_or_create(&claims.username, &claims.server_url)
+            .await
+            .map_err(|e| ApiError::Database(format!("Failed to get user: {}", e)))
+    }
+
     /// Create CalDAV config from token
     pub fn caldav_config_from_token(
         &self,

backend/src/db.rs

@@ -1,4 +1,4 @@
-use chrono::{DateTime, Utc};
+use chrono::{DateTime, Duration, Utc};
 use serde::{Deserialize, Serialize};
 use sqlx::sqlite::{SqlitePool, SqlitePoolOptions};
 use sqlx::{FromRow, Result};
@@ -99,6 +99,38 @@ pub struct UserPreferences {
     pub updated_at: DateTime<Utc>,
 }
 
+/// External calendar model
+#[derive(Debug, Clone, Serialize, Deserialize, FromRow)]
+pub struct ExternalCalendar {
+    pub id: i32,
+    pub user_id: String,
+    pub name: String,
+    pub url: String,
+    pub color: String,
+    pub is_visible: bool,
+    pub created_at: DateTime<Utc>,
+    pub updated_at: DateTime<Utc>,
+    pub last_fetched: Option<DateTime<Utc>>,
+}
+
+impl ExternalCalendar {
+    /// Create a new external calendar
+    pub fn new(user_id: String, name: String, url: String, color: String) -> Self {
+        let now = Utc::now();
+        Self {
+            id: 0, // Will be set by database
+            user_id,
+            name,
+            url,
+            color,
+            is_visible: true,
+            created_at: now,
+            updated_at: now,
+            last_fetched: None,
+        }
+    }
+}
+
 impl UserPreferences {
     /// Create default preferences for a new user
     pub fn default_for_user(user_id: String) -> Self {
@@ -308,6 +340,149 @@ impl<'a> PreferencesRepository<'a> {
         .execute(self.db.pool())
         .await?;
 
+        Ok(())
+    }
+}
+
+/// Repository for ExternalCalendar operations
+pub struct ExternalCalendarRepository<'a> {
+    db: &'a Database,
+}
+
+impl<'a> ExternalCalendarRepository<'a> {
+    pub fn new(db: &'a Database) -> Self {
+        Self { db }
+    }
+
+    /// Get all external calendars for a user
+    pub async fn get_by_user(&self, user_id: &str) -> Result<Vec<ExternalCalendar>> {
+        sqlx::query_as::<_, ExternalCalendar>(
+            "SELECT * FROM external_calendars WHERE user_id = ? ORDER BY created_at ASC",
+        )
+        .bind(user_id)
+        .fetch_all(self.db.pool())
+        .await
+    }
+
+    /// Create a new external calendar
+    pub async fn create(&self, calendar: &ExternalCalendar) -> Result<i32> {
+        let result = sqlx::query(
+            "INSERT INTO external_calendars (user_id, name, url, color, is_visible, created_at, updated_at) 
+             VALUES (?, ?, ?, ?, ?, ?, ?)",
+        )
+        .bind(&calendar.user_id)
+        .bind(&calendar.name)
+        .bind(&calendar.url)
+        .bind(&calendar.color)
+        .bind(&calendar.is_visible)
+        .bind(&calendar.created_at)
+        .bind(&calendar.updated_at)
+        .execute(self.db.pool())
+        .await?;
+
+        Ok(result.last_insert_rowid() as i32)
+    }
+
+    /// Update an external calendar
+    pub async fn update(&self, id: i32, calendar: &ExternalCalendar) -> Result<()> {
+        sqlx::query(
+            "UPDATE external_calendars 
+             SET name = ?, url = ?, color = ?, is_visible = ?, updated_at = ?
+             WHERE id = ? AND user_id = ?",
+        )
+        .bind(&calendar.name)
+        .bind(&calendar.url)
+        .bind(&calendar.color)
+        .bind(&calendar.is_visible)
+        .bind(Utc::now())
+        .bind(id)
+        .bind(&calendar.user_id)
+        .execute(self.db.pool())
+        .await?;
+
+        Ok(())
+    }
+
+    /// Delete an external calendar
+    pub async fn delete(&self, id: i32, user_id: &str) -> Result<()> {
+        sqlx::query("DELETE FROM external_calendars WHERE id = ? AND user_id = ?")
+            .bind(id)
+            .bind(user_id)
+            .execute(self.db.pool())
+            .await?;
+
+        Ok(())
+    }
+
+    /// Update last_fetched timestamp
+    pub async fn update_last_fetched(&self, id: i32, user_id: &str) -> Result<()> {
+        sqlx::query(
+            "UPDATE external_calendars SET last_fetched = ? WHERE id = ? AND user_id = ?",
+        )
+        .bind(Utc::now())
+        .bind(id)
+        .bind(user_id)
+        .execute(self.db.pool())
+        .await?;
+
+        Ok(())
+    }
+
+    /// Get cached ICS data for an external calendar
+    pub async fn get_cached_data(&self, external_calendar_id: i32) -> Result<Option<(String, DateTime<Utc>)>> {
+        let result = sqlx::query_as::<_, (String, DateTime<Utc>)>(
+            "SELECT ics_data, cached_at FROM external_calendar_cache WHERE external_calendar_id = ?",
+        )
+        .bind(external_calendar_id)
+        .fetch_optional(self.db.pool())
+        .await?;
+
+        Ok(result)
+    }
+
+    /// Update cache with new ICS data
+    pub async fn update_cache(&self, external_calendar_id: i32, ics_data: &str, etag: Option<&str>) -> Result<()> {
+        sqlx::query(
+            "INSERT INTO external_calendar_cache (external_calendar_id, ics_data, etag, cached_at)
+             VALUES (?, ?, ?, ?)
+             ON CONFLICT(external_calendar_id) DO UPDATE SET
+             ics_data = excluded.ics_data,
+             etag = excluded.etag,
+             cached_at = excluded.cached_at",
+        )
+        .bind(external_calendar_id)
+        .bind(ics_data)
+        .bind(etag)
+        .bind(Utc::now())
+        .execute(self.db.pool())
+        .await?;
+
+        Ok(())
+    }
+
+    /// Check if cache is stale (older than max_age_minutes)
+    pub async fn is_cache_stale(&self, external_calendar_id: i32, max_age_minutes: i64) -> Result<bool> {
+        let cutoff_time = Utc::now() - Duration::minutes(max_age_minutes);
+        
+        let result = sqlx::query_scalar::<_, i64>(
+            "SELECT COUNT(*) FROM external_calendar_cache 
+             WHERE external_calendar_id = ? AND cached_at > ?",
+        )
+        .bind(external_calendar_id)
+        .bind(cutoff_time)
+        .fetch_one(self.db.pool())
+        .await?;
+
+        Ok(result == 0)
+    }
+
+    /// Clear cache for an external calendar
+    pub async fn clear_cache(&self, external_calendar_id: i32) -> Result<()> {
+        sqlx::query("DELETE FROM external_calendar_cache WHERE external_calendar_id = ?")
+            .bind(external_calendar_id)
+            .execute(self.db.pool())
+            .await?;
+
         Ok(())
     }
 }

backend/src/handlers.rs

@@ -1,12 +0,0 @@
-// Re-export all handlers from the modular structure
-mod auth;
-mod calendar;
-mod events;
-mod preferences;
-mod series;
-
-pub use auth::{get_user_info, login, verify_token};
-pub use calendar::{create_calendar, delete_calendar};
-pub use events::{create_event, delete_event, get_calendar_events, refresh_event, update_event};
-pub use preferences::{get_preferences, logout, update_preferences};
-pub use series::{create_event_series, delete_event_series, update_event_series};

backend/src/handlers/auth.rs

@@ -93,6 +93,7 @@ pub async fn get_user_info(
             path: path.clone(),
             display_name: extract_calendar_name(path),
             color: generate_calendar_color(path),
+            is_visible: true, // Default to visible
         })
         .collect();
 

backend/src/handlers/external_calendars.rs

@@ -0,0 +1,142 @@
+use axum::{
+    extract::{Path, State},
+    response::Json,
+};
+use serde::{Deserialize, Serialize};
+use std::sync::Arc;
+
+use crate::{
+    db::{ExternalCalendar, ExternalCalendarRepository},
+    models::ApiError,
+    AppState,
+};
+
+use super::auth::{extract_bearer_token};
+
+#[derive(Debug, Deserialize)]
+pub struct CreateExternalCalendarRequest {
+    pub name: String,
+    pub url: String,
+    pub color: String,
+}
+
+#[derive(Debug, Deserialize)]
+pub struct UpdateExternalCalendarRequest {
+    pub name: String,
+    pub url: String,
+    pub color: String,
+    pub is_visible: bool,
+}
+
+#[derive(Debug, Serialize)]
+pub struct ExternalCalendarResponse {
+    pub id: i32,
+    pub name: String,
+    pub url: String,
+    pub color: String,
+    pub is_visible: bool,
+    pub created_at: chrono::DateTime<chrono::Utc>,
+    pub updated_at: chrono::DateTime<chrono::Utc>,
+    pub last_fetched: Option<chrono::DateTime<chrono::Utc>>,
+}
+
+impl From<ExternalCalendar> for ExternalCalendarResponse {
+    fn from(calendar: ExternalCalendar) -> Self {
+        Self {
+            id: calendar.id,
+            name: calendar.name,
+            url: calendar.url,
+            color: calendar.color,
+            is_visible: calendar.is_visible,
+            created_at: calendar.created_at,
+            updated_at: calendar.updated_at,
+            last_fetched: calendar.last_fetched,
+        }
+    }
+}
+
+pub async fn get_external_calendars(
+    headers: axum::http::HeaderMap,
+    State(app_state): State<Arc<AppState>>,
+) -> Result<Json<Vec<ExternalCalendarResponse>>, ApiError> {
+    // Extract and verify token, get user
+    let token = extract_bearer_token(&headers)?;
+    let user = app_state.auth_service.get_user_from_token(&token).await?;
+
+    let repo = ExternalCalendarRepository::new(&app_state.db);
+    let calendars = repo
+        .get_by_user(&user.id)
+        .await
+        .map_err(|e| ApiError::Database(format!("Failed to get external calendars: {}", e)))?;
+
+    let response: Vec<ExternalCalendarResponse> = calendars.into_iter().map(Into::into).collect();
+    Ok(Json(response))
+}
+
+pub async fn create_external_calendar(
+    headers: axum::http::HeaderMap,
+    State(app_state): State<Arc<AppState>>,
+    Json(request): Json<CreateExternalCalendarRequest>,
+) -> Result<Json<ExternalCalendarResponse>, ApiError> {
+    let token = extract_bearer_token(&headers)?;
+    let user = app_state.auth_service.get_user_from_token(&token).await?;
+
+    let calendar = ExternalCalendar::new(
+        user.id,
+        request.name,
+        request.url,
+        request.color,
+    );
+
+    let repo = ExternalCalendarRepository::new(&app_state.db);
+    let id = repo
+        .create(&calendar)
+        .await
+        .map_err(|e| ApiError::Database(format!("Failed to create external calendar: {}", e)))?;
+
+    let mut created_calendar = calendar;
+    created_calendar.id = id;
+
+    Ok(Json(created_calendar.into()))
+}
+
+pub async fn update_external_calendar(
+    headers: axum::http::HeaderMap,
+    State(app_state): State<Arc<AppState>>,
+    Path(id): Path<i32>,
+    Json(request): Json<UpdateExternalCalendarRequest>,
+) -> Result<Json<()>, ApiError> {
+    let token = extract_bearer_token(&headers)?;
+    let user = app_state.auth_service.get_user_from_token(&token).await?;
+
+    let mut calendar = ExternalCalendar::new(
+        user.id,
+        request.name,
+        request.url,
+        request.color,
+    );
+    calendar.is_visible = request.is_visible;
+
+    let repo = ExternalCalendarRepository::new(&app_state.db);
+    repo.update(id, &calendar)
+        .await
+        .map_err(|e| ApiError::Database(format!("Failed to update external calendar: {}", e)))?;
+
+    Ok(Json(()))
+}
+
+pub async fn delete_external_calendar(
+    headers: axum::http::HeaderMap,
+    State(app_state): State<Arc<AppState>>,
+    Path(id): Path<i32>,
+) -> Result<Json<()>, ApiError> {
+    let token = extract_bearer_token(&headers)?;
+    let user = app_state.auth_service.get_user_from_token(&token).await?;
+
+    let repo = ExternalCalendarRepository::new(&app_state.db);
+    repo.delete(id, &user.id)
+        .await
+        .map_err(|e| ApiError::Database(format!("Failed to delete external calendar: {}", e)))?;
+
+    Ok(Json(()))
+}

backend/src/handlers/ics_fetcher.rs

@@ -0,0 +1,410 @@
+use axum::{
+    extract::{Path, State},
+    response::Json,
+};
+use chrono::{DateTime, Utc};
+use ical::parser::ical::component::IcalEvent;
+use reqwest::Client;
+use serde::Serialize;
+use std::sync::Arc;
+
+use crate::{
+    db::ExternalCalendarRepository,
+    models::ApiError,
+    AppState,
+};
+
+// Import VEvent from calendar-models shared crate
+use calendar_models::VEvent;
+
+use super::auth::{extract_bearer_token};
+
+#[derive(Debug, Serialize)]
+pub struct ExternalCalendarEventsResponse {
+    pub events: Vec<VEvent>,
+    pub last_fetched: DateTime<Utc>,
+}
+
+pub async fn fetch_external_calendar_events(
+    headers: axum::http::HeaderMap,
+    State(app_state): State<Arc<AppState>>,
+    Path(id): Path<i32>,
+) -> Result<Json<ExternalCalendarEventsResponse>, ApiError> {
+    let token = extract_bearer_token(&headers)?;
+    let user = app_state.auth_service.get_user_from_token(&token).await?;
+
+    let repo = ExternalCalendarRepository::new(&app_state.db);
+    
+    // Get user's external calendars to verify ownership and get URL
+    let calendars = repo
+        .get_by_user(&user.id)
+        .await
+        .map_err(|e| ApiError::Database(format!("Failed to get external calendars: {}", e)))?;
+
+    let calendar = calendars
+        .into_iter()
+        .find(|c| c.id == id)
+        .ok_or_else(|| ApiError::NotFound("External calendar not found".to_string()))?;
+
+    if !calendar.is_visible {
+        return Ok(Json(ExternalCalendarEventsResponse {
+            events: vec![],
+            last_fetched: Utc::now(),
+        }));
+    }
+
+    // Check cache first
+    let cache_max_age_minutes = 5;
+    let mut ics_content = String::new();
+    let mut last_fetched = Utc::now();
+    let mut fetched_from_cache = false;
+
+    // Try to get from cache if not stale
+    match repo.is_cache_stale(id, cache_max_age_minutes).await {
+        Ok(is_stale) => {
+            if !is_stale {
+                // Cache is fresh, use it
+                if let Ok(Some((cached_data, cached_at))) = repo.get_cached_data(id).await {
+                    ics_content = cached_data;
+                    last_fetched = cached_at;
+                    fetched_from_cache = true;
+                }
+            }
+        }
+        Err(_) => {
+            // If cache check fails, proceed to fetch from URL
+        }
+    }
+
+    // If not fetched from cache, get from external URL
+    if !fetched_from_cache {
+        let client = Client::new();
+        let response = client
+            .get(&calendar.url)
+            .send()
+            .await
+            .map_err(|e| ApiError::Internal(format!("Failed to fetch calendar: {}", e)))?;
+
+        if !response.status().is_success() {
+            return Err(ApiError::Internal(format!("Calendar server returned: {}", response.status())));
+        }
+
+        ics_content = response
+            .text()
+            .await
+            .map_err(|e| ApiError::Internal(format!("Failed to read calendar content: {}", e)))?;
+
+        // Store in cache for future requests
+        let etag = None; // TODO: Extract ETag from response headers if available
+        if let Err(_) = repo.update_cache(id, &ics_content, etag).await {
+            // Log error but don't fail the request
+        }
+
+        // Update last_fetched timestamp
+        if let Err(_) = repo.update_last_fetched(id, &user.id).await {
+        }
+        
+        last_fetched = Utc::now();
+    }
+
+    // Parse ICS content
+    let events = parse_ics_content(&ics_content)
+        .map_err(|e| ApiError::BadRequest(format!("Failed to parse calendar: {}", e)))?;
+
+    Ok(Json(ExternalCalendarEventsResponse {
+        events,
+        last_fetched,
+    }))
+}
+
+fn parse_ics_content(ics_content: &str) -> Result<Vec<VEvent>, Box<dyn std::error::Error>> {
+    let reader = ical::IcalParser::new(ics_content.as_bytes());
+    let mut events = Vec::new();
+    let mut _total_components = 0;
+    let mut _failed_conversions = 0;
+
+    for calendar in reader {
+        let calendar = calendar?;
+        for component in calendar.events {
+            _total_components += 1;
+            match convert_ical_to_vevent(component) {
+                Ok(vevent) => {
+                    events.push(vevent);
+                }
+                Err(_) => {
+                    _failed_conversions += 1;
+                }
+            }
+        }
+    }
+
+
+    Ok(events)
+}
+
+fn convert_ical_to_vevent(ical_event: IcalEvent) -> Result<VEvent, Box<dyn std::error::Error>> {
+    use uuid::Uuid;
+
+    let mut summary = None;
+    let mut description = None;
+    let mut location = None;
+    let mut dtstart = None;
+    let mut dtend = None;
+    let mut uid = None;
+    let mut all_day = false;
+    let mut rrule = None;
+
+
+    // Extract properties
+    for property in ical_event.properties {
+        match property.name.as_str() {
+            "SUMMARY" => {
+                summary = property.value;
+            }
+            "DESCRIPTION" => {
+                description = property.value;
+            }
+            "LOCATION" => {
+                location = property.value;
+            }
+            "DTSTART" => {
+                if let Some(value) = property.value {
+                    // Check if it's a date-only value (all-day event)
+                    if value.len() == 8 && !value.contains('T') {
+                        all_day = true;
+                        // Parse YYYYMMDD format
+                        if let Ok(date) = chrono::NaiveDate::parse_from_str(&value, "%Y%m%d") {
+                            dtstart = Some(chrono::TimeZone::from_utc_datetime(&Utc, &date.and_hms_opt(12, 0, 0).unwrap()));
+                        }
+                    } else {
+                        // Extract timezone info from parameters
+                        let tzid = property.params.as_ref()
+                            .and_then(|params| params.iter().find(|(k, _)| k == "TZID"))
+                            .and_then(|(_, v)| v.first().cloned());
+                        
+                        // Parse datetime with timezone information
+                        if let Some(dt) = parse_datetime_with_tz(&value, tzid.as_deref()) {
+                            dtstart = Some(dt);
+                        }
+                    }
+                }
+            }
+            "DTEND" => {
+                if let Some(value) = property.value {
+                    if all_day && value.len() == 8 && !value.contains('T') {
+                        // For all-day events, DTEND is exclusive so use the date as-is at noon
+                        if let Ok(date) = chrono::NaiveDate::parse_from_str(&value, "%Y%m%d") {
+                            dtend = Some(chrono::TimeZone::from_utc_datetime(&Utc, &date.and_hms_opt(12, 0, 0).unwrap()));
+                        }
+                    } else {
+                        // Extract timezone info from parameters
+                        let tzid = property.params.as_ref()
+                            .and_then(|params| params.iter().find(|(k, _)| k == "TZID"))
+                            .and_then(|(_, v)| v.first().cloned());
+                        
+                        // Parse datetime with timezone information
+                        if let Some(dt) = parse_datetime_with_tz(&value, tzid.as_deref()) {
+                            dtend = Some(dt);
+                        }
+                    }
+                }
+            }
+            "UID" => {
+                uid = property.value;
+            }
+            "RRULE" => {
+                rrule = property.value;
+            }
+            _ => {} // Ignore other properties for now
+        }
+    }
+
+
+    let dtstart = dtstart.ok_or("Missing DTSTART")?;
+
+    let vevent = VEvent {
+        uid: uid.unwrap_or_else(|| Uuid::new_v4().to_string()),
+        dtstart,
+        dtend,
+        summary,
+        description,
+        location,
+        all_day,
+        rrule,
+        exdate: Vec::new(), // External calendars don't need exception handling
+        recurrence_id: None,
+        created: None,
+        last_modified: None,
+        dtstamp: Utc::now(),
+        sequence: Some(0),
+        status: None,
+        transp: None,
+        organizer: None,
+        attendees: Vec::new(),
+        url: None,
+        attachments: Vec::new(),
+        categories: Vec::new(),
+        priority: None,
+        resources: Vec::new(),
+        related_to: None,
+        geo: None,
+        duration: None,
+        class: None,
+        contact: None,
+        comment: None,
+        rdate: Vec::new(),
+        alarms: Vec::new(),
+        etag: None,
+        href: None,
+        calendar_path: None,
+    };
+
+    Ok(vevent)
+}
+
+fn parse_datetime_with_tz(datetime_str: &str, tzid: Option<&str>) -> Option<DateTime<Utc>> {
+    use chrono::TimeZone;
+    use chrono_tz::Tz;
+    
+    
+    // Try various datetime formats commonly found in ICS files
+    
+    // Format: 20231201T103000Z (UTC) - handle as naive datetime first
+    if datetime_str.ends_with('Z') {
+        let datetime_without_z = &datetime_str[..datetime_str.len()-1];
+        if let Ok(naive_dt) = chrono::NaiveDateTime::parse_from_str(datetime_without_z, "%Y%m%dT%H%M%S") {
+            return Some(naive_dt.and_utc());
+        }
+    }
+
+    // Format: 20231201T103000-0500 (with timezone offset)
+    if let Ok(dt) = DateTime::parse_from_str(datetime_str, "%Y%m%dT%H%M%S%z") {
+        return Some(dt.with_timezone(&Utc));
+    }
+
+    // Format: 2023-12-01T10:30:00Z (ISO format)
+    if let Ok(dt) = DateTime::parse_from_str(datetime_str, "%Y-%m-%dT%H:%M:%SZ") {
+        return Some(dt.with_timezone(&Utc));
+    }
+
+    // Handle naive datetime with timezone parameter
+    let naive_dt = if let Ok(dt) = chrono::NaiveDateTime::parse_from_str(datetime_str, "%Y%m%dT%H%M%S") {
+        Some(dt)
+    } else if let Ok(dt) = chrono::NaiveDateTime::parse_from_str(datetime_str, "%Y-%m-%dT%H:%M:%S") {
+        Some(dt)
+    } else {
+        None
+    };
+
+    if let Some(naive_dt) = naive_dt {
+        // If TZID is provided, try to parse it
+        if let Some(tzid_str) = tzid {
+            // Handle common timezone formats
+            let tz_result = if tzid_str.starts_with("/mozilla.org/") {
+                // Mozilla/Thunderbird format: /mozilla.org/20070129_1/Europe/London
+                tzid_str.split('/').last().and_then(|tz_name| tz_name.parse::<Tz>().ok())
+            } else if tzid_str.contains('/') {
+                // Standard timezone format: America/New_York, Europe/London
+                tzid_str.parse::<Tz>().ok()
+            } else {
+                // Try common abbreviations and Windows timezone names
+                match tzid_str {
+                    // Standard abbreviations
+                    "EST" => Some(Tz::America__New_York),
+                    "PST" => Some(Tz::America__Los_Angeles),
+                    "MST" => Some(Tz::America__Denver), 
+                    "CST" => Some(Tz::America__Chicago),
+                    
+                    // North America - Windows timezone names to IANA mapping
+                    "Mountain Standard Time" => Some(Tz::America__Denver),
+                    "Eastern Standard Time" => Some(Tz::America__New_York),
+                    "Central Standard Time" => Some(Tz::America__Chicago),
+                    "Pacific Standard Time" => Some(Tz::America__Los_Angeles),
+                    "Mountain Daylight Time" => Some(Tz::America__Denver),
+                    "Eastern Daylight Time" => Some(Tz::America__New_York),
+                    "Central Daylight Time" => Some(Tz::America__Chicago),
+                    "Pacific Daylight Time" => Some(Tz::America__Los_Angeles),
+                    "Hawaiian Standard Time" => Some(Tz::Pacific__Honolulu),
+                    "Alaskan Standard Time" => Some(Tz::America__Anchorage),
+                    "Alaskan Daylight Time" => Some(Tz::America__Anchorage),
+                    "Atlantic Standard Time" => Some(Tz::America__Halifax),
+                    "Newfoundland Standard Time" => Some(Tz::America__St_Johns),
+                    
+                    // Europe
+                    "GMT Standard Time" => Some(Tz::Europe__London),
+                    "Greenwich Standard Time" => Some(Tz::UTC),
+                    "W. Europe Standard Time" => Some(Tz::Europe__Berlin),
+                    "Central Europe Standard Time" => Some(Tz::Europe__Warsaw),
+                    "Romance Standard Time" => Some(Tz::Europe__Paris),
+                    "Central European Standard Time" => Some(Tz::Europe__Belgrade),
+                    "E. Europe Standard Time" => Some(Tz::Europe__Bucharest),
+                    "FLE Standard Time" => Some(Tz::Europe__Helsinki),
+                    "GTB Standard Time" => Some(Tz::Europe__Athens),
+                    "Russian Standard Time" => Some(Tz::Europe__Moscow),
+                    "Turkey Standard Time" => Some(Tz::Europe__Istanbul),
+                    
+                    // Asia
+                    "China Standard Time" => Some(Tz::Asia__Shanghai),
+                    "Tokyo Standard Time" => Some(Tz::Asia__Tokyo),
+                    "Korea Standard Time" => Some(Tz::Asia__Seoul),
+                    "Singapore Standard Time" => Some(Tz::Asia__Singapore),
+                    "India Standard Time" => Some(Tz::Asia__Kolkata),
+                    "Pakistan Standard Time" => Some(Tz::Asia__Karachi),
+                    "Bangladesh Standard Time" => Some(Tz::Asia__Dhaka),
+                    "Thailand Standard Time" => Some(Tz::Asia__Bangkok),
+                    "SE Asia Standard Time" => Some(Tz::Asia__Bangkok),
+                    "Myanmar Standard Time" => Some(Tz::Asia__Yangon),
+                    "Sri Lanka Standard Time" => Some(Tz::Asia__Colombo),
+                    "Nepal Standard Time" => Some(Tz::Asia__Kathmandu),
+                    "Central Asia Standard Time" => Some(Tz::Asia__Almaty),
+                    "West Asia Standard Time" => Some(Tz::Asia__Tashkent),
+                    "Afghanistan Standard Time" => Some(Tz::Asia__Kabul),
+                    "Iran Standard Time" => Some(Tz::Asia__Tehran),
+                    "Arabian Standard Time" => Some(Tz::Asia__Dubai),
+                    "Arab Standard Time" => Some(Tz::Asia__Riyadh),
+                    "Israel Standard Time" => Some(Tz::Asia__Jerusalem),
+                    "Jordan Standard Time" => Some(Tz::Asia__Amman),
+                    "Syria Standard Time" => Some(Tz::Asia__Damascus),
+                    "Middle East Standard Time" => Some(Tz::Asia__Beirut),
+                    "Egypt Standard Time" => Some(Tz::Africa__Cairo),
+                    "South Africa Standard Time" => Some(Tz::Africa__Johannesburg),
+                    "E. Africa Standard Time" => Some(Tz::Africa__Nairobi),
+                    "W. Central Africa Standard Time" => Some(Tz::Africa__Lagos),
+                    
+                    // Asia Pacific
+                    "AUS Eastern Standard Time" => Some(Tz::Australia__Sydney),
+                    "AUS Central Standard Time" => Some(Tz::Australia__Darwin),
+                    "W. Australia Standard Time" => Some(Tz::Australia__Perth),
+                    "Tasmania Standard Time" => Some(Tz::Australia__Hobart),
+                    "New Zealand Standard Time" => Some(Tz::Pacific__Auckland),
+                    "Fiji Standard Time" => Some(Tz::Pacific__Fiji),
+                    "Tonga Standard Time" => Some(Tz::Pacific__Tongatapu),
+                    
+                    // South America
+                    "Argentina Standard Time" => Some(Tz::America__Buenos_Aires),
+                    "E. South America Standard Time" => Some(Tz::America__Sao_Paulo),
+                    "SA Eastern Standard Time" => Some(Tz::America__Cayenne),
+                    "SA Pacific Standard Time" => Some(Tz::America__Bogota),
+                    "SA Western Standard Time" => Some(Tz::America__La_Paz),
+                    "Pacific SA Standard Time" => Some(Tz::America__Santiago),
+                    "Venezuela Standard Time" => Some(Tz::America__Caracas),
+                    "Montevideo Standard Time" => Some(Tz::America__Montevideo),
+                    
+                    // Try parsing as IANA name
+                    _ => tzid_str.parse::<Tz>().ok()
+                }
+            };
+
+            if let Some(tz) = tz_result {
+                if let Some(dt_with_tz) = tz.from_local_datetime(&naive_dt).single() {
+                    return Some(dt_with_tz.with_timezone(&Utc));
+                }
+            }
+        }
+        
+        // If no timezone info or parsing failed, treat as UTC (safer than local time assumptions)
+        return Some(chrono::TimeZone::from_utc_datetime(&Utc, &naive_dt));
+    }
+
+    None
+}

backend/src/handlers/mod.rs

@@ -0,0 +1,15 @@
+pub mod auth;
+pub mod calendar;
+pub mod events;
+pub mod external_calendars;
+pub mod ics_fetcher;
+pub mod preferences;
+pub mod series;
+
+pub use auth::*;
+pub use calendar::*;
+pub use events::*;
+pub use external_calendars::*;
+pub use ics_fetcher::*;
+pub use preferences::*;
+pub use series::*;

backend/src/lib.rs

@@ -1,6 +1,6 @@
 use axum::{
     response::Json,
-    routing::{get, post},
+    routing::{delete, get, post},
     Router,
 };
 use std::sync::Arc;
@@ -72,6 +72,12 @@ pub async fn run_server() -> Result<(), Box<dyn std::error::Error>> {
         .route("/api/preferences", get(handlers::get_preferences))
         .route("/api/preferences", post(handlers::update_preferences))
         .route("/api/auth/logout", post(handlers::logout))
+        // External calendars endpoints
+        .route("/api/external-calendars", get(handlers::get_external_calendars))
+        .route("/api/external-calendars", post(handlers::create_external_calendar))
+        .route("/api/external-calendars/:id", post(handlers::update_external_calendar))
+        .route("/api/external-calendars/:id", delete(handlers::delete_external_calendar))
+        .route("/api/external-calendars/:id/events", get(handlers::fetch_external_calendar_events))
         .layer(
             CorsLayer::new()
                 .allow_origin(Any)

backend/src/models.rs

@@ -56,6 +56,7 @@ pub struct CalendarInfo {
     pub path: String,
     pub display_name: String,
     pub color: String,
+    pub is_visible: bool,
 }
 
 #[derive(Debug, Deserialize)]

frontend/Cargo.toml

@@ -37,6 +37,7 @@ reqwest = { version = "0.11", features = ["json"] }
 ical = "0.7"
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
+serde-wasm-bindgen = "0.6"
 
 # Date and time handling
 chrono = { version = "0.4", features = ["serde", "wasm-bindgen"] }

frontend/src/app.rs

@@ -1,12 +1,14 @@
 use crate::components::{
     CalendarContextMenu, ContextMenu, CreateCalendarModal, CreateEventModal, DeleteAction,
-    EditAction, EventContextMenu, EventCreationData, RouteHandler, Sidebar, Theme, ViewMode,
+    EditAction, EventContextMenu, EventCreationData, ExternalCalendarModal, RouteHandler, 
+    Sidebar, Theme, ViewMode,
 };
 use crate::components::sidebar::{Style};
 use crate::models::ical::VEvent;
-use crate::services::{calendar_service::UserInfo, CalendarService};
+use crate::services::{calendar_service::{UserInfo, ExternalCalendar}, CalendarService};
 use chrono::NaiveDate;
 use gloo_storage::{LocalStorage, Storage};
+use gloo_timers::callback::Interval;
 use wasm_bindgen::JsCast;
 use web_sys::MouseEvent;
 use yew::prelude::*;
@@ -73,6 +75,12 @@ pub fn App() -> Html {
     let _recurring_edit_modal_open = use_state(|| false);
     let _recurring_edit_event = use_state(|| -> Option<VEvent> { None });
     let _recurring_edit_data = use_state(|| -> Option<EventCreationData> { None });
+    
+    // External calendar state
+    let external_calendars = use_state(|| -> Vec<ExternalCalendar> { Vec::new() });
+    let external_calendar_events = use_state(|| -> Vec<VEvent> { Vec::new() });
+    let external_calendar_modal_open = use_state(|| false);
+    let refresh_interval = use_state(|| -> Option<Interval> { None });
 
     // Calendar view state - load from localStorage if available
     let current_view = use_state(|| {
@@ -301,6 +309,80 @@ pub fn App() -> Html {
         });
     }
 
+    // Function to refresh external calendars
+    let refresh_external_calendars = {
+        let external_calendars = external_calendars.clone();
+        let external_calendar_events = external_calendar_events.clone();
+        Callback::from(move |_| {
+            let external_calendars = external_calendars.clone();
+            let external_calendar_events = external_calendar_events.clone();
+
+            wasm_bindgen_futures::spawn_local(async move {
+                // Load external calendars
+                match CalendarService::get_external_calendars().await {
+                    Ok(calendars) => {
+                        external_calendars.set(calendars.clone());
+                        
+                        // Load events for visible external calendars
+                        let mut all_events = Vec::new();
+                        for calendar in calendars {
+                            if calendar.is_visible {
+                                if let Ok(mut events) = CalendarService::fetch_external_calendar_events(calendar.id).await {
+                                    // Set calendar_path for color matching
+                                    for event in &mut events {
+                                        event.calendar_path = Some(format!("external_{}", calendar.id));
+                                    }
+                                    all_events.extend(events);
+                                }
+                            }
+                        }
+                        external_calendar_events.set(all_events);
+                    }
+                    Err(err) => {
+                        web_sys::console::log_1(
+                            &format!("Failed to load external calendars: {}", err).into(),
+                        );
+                    }
+                }
+            });
+        })
+    };
+
+    // Load external calendars when auth token is available and set up auto-refresh
+    {
+        let auth_token = auth_token.clone();
+        let refresh_external_calendars = refresh_external_calendars.clone();
+        let refresh_interval = refresh_interval.clone();
+        let external_calendars = external_calendars.clone();
+        let external_calendar_events = external_calendar_events.clone();
+
+        use_effect_with((*auth_token).clone(), move |token| {
+            if let Some(_) = token {
+                // Initial load
+                refresh_external_calendars.emit(());
+                
+                // Set up 5-minute refresh interval
+                let refresh_external_calendars = refresh_external_calendars.clone();
+                let interval = Interval::new(5 * 60 * 1000, move || {
+                    refresh_external_calendars.emit(());
+                });
+                refresh_interval.set(Some(interval));
+            } else {
+                // Clear data and interval when logged out
+                external_calendars.set(Vec::new());
+                external_calendar_events.set(Vec::new());
+                refresh_interval.set(None);
+            }
+
+            // Cleanup function
+            let refresh_interval = refresh_interval.clone();
+            move || {
+                // Clear interval on cleanup
+                refresh_interval.set(None);
+            }
+        });
+    }
+
     let on_outside_click = {
         let color_picker_open = color_picker_open.clone();
         let context_menu_open = context_menu_open.clone();
@@ -924,11 +1006,146 @@ pub fn App() -> Html {
                                         let create_modal_open = create_modal_open.clone();
                                         move |_| create_modal_open.set(true)
                                     })}
+                                    on_create_external_calendar={Callback::from({
+                                        let external_calendar_modal_open = external_calendar_modal_open.clone();
+                                        move |_| external_calendar_modal_open.set(true)
+                                    })}
+                                    external_calendars={(*external_calendars).clone()}
+                                    on_external_calendar_toggle={Callback::from({
+                                        let external_calendars = external_calendars.clone();
+                                        let external_calendar_events = external_calendar_events.clone();
+                                        move |id: i32| {
+                                            let external_calendars = external_calendars.clone();
+                                            let external_calendar_events = external_calendar_events.clone();
+                                            wasm_bindgen_futures::spawn_local(async move {
+                                                // Find the calendar and toggle its visibility
+                                                let mut calendars = (*external_calendars).clone();
+                                                if let Some(calendar) = calendars.iter_mut().find(|c| c.id == id) {
+                                                    calendar.is_visible = !calendar.is_visible;
+                                                    
+                                                    // Update on server
+                                                    if let Err(err) = CalendarService::update_external_calendar(
+                                                        calendar.id,
+                                                        &calendar.name,
+                                                        &calendar.url,
+                                                        &calendar.color,
+                                                        calendar.is_visible,
+                                                    ).await {
+                                                        web_sys::console::log_1(
+                                                            &format!("Failed to update external calendar: {}", err).into(),
+                                                        );
+                                                        return;
+                                                    }
+                                                    
+                                                    external_calendars.set(calendars.clone());
+                                                    
+                                                    // Reload events for all visible external calendars  
+                                                    let mut all_events = Vec::new();
+                                                    for cal in calendars {
+                                                        if cal.is_visible {
+                                                            if let Ok(mut events) = CalendarService::fetch_external_calendar_events(cal.id).await {
+                                                                // Set calendar_path for color matching
+                                                                for event in &mut events {
+                                                                    event.calendar_path = Some(format!("external_{}", cal.id));
+                                                                }
+                                                                all_events.extend(events);
+                                                            }
+                                                        }
+                                                    }
+                                                    external_calendar_events.set(all_events);
+                                                }
+                                            });
+                                        }
+                                    })}
+                                    on_external_calendar_delete={Callback::from({
+                                        let external_calendars = external_calendars.clone();
+                                        let external_calendar_events = external_calendar_events.clone();
+                                        move |id: i32| {
+                                            let external_calendars = external_calendars.clone();
+                                            let external_calendar_events = external_calendar_events.clone();
+                                            wasm_bindgen_futures::spawn_local(async move {
+                                                // Delete the external calendar from the server
+                                                if let Err(err) = CalendarService::delete_external_calendar(id).await {
+                                                    web_sys::console::log_1(
+                                                        &format!("Failed to delete external calendar: {}", err).into(),
+                                                    );
+                                                    return;
+                                                }
+                                                
+                                                // Remove calendar from local state
+                                                let mut calendars = (*external_calendars).clone();
+                                                calendars.retain(|c| c.id != id);
+                                                external_calendars.set(calendars.clone());
+                                                
+                                                // Remove events from this calendar
+                                                let mut events = (*external_calendar_events).clone();
+                                                events.retain(|e| {
+                                                    if let Some(ref calendar_path) = e.calendar_path {
+                                                        calendar_path != &format!("external_{}", id)
+                                                    } else {
+                                                        true
+                                                    }
+                                                });
+                                                external_calendar_events.set(events);
+                                            });
+                                        }
+                                    })}
+                                    on_external_calendar_refresh={Callback::from({
+                                        let external_calendar_events = external_calendar_events.clone();
+                                        let external_calendars = external_calendars.clone();
+                                        move |id: i32| {
+                                            let external_calendar_events = external_calendar_events.clone();
+                                            let external_calendars = external_calendars.clone();
+                                            wasm_bindgen_futures::spawn_local(async move {
+                                                // Force refresh of this specific calendar
+                                                if let Ok(mut events) = CalendarService::fetch_external_calendar_events(id).await {
+                                                    // Set calendar_path for color matching
+                                                    for event in &mut events {
+                                                        event.calendar_path = Some(format!("external_{}", id));
+                                                    }
+                                                    
+                                                    // Update events for this calendar
+                                                    let mut all_events = (*external_calendar_events).clone();
+                                                    // Remove old events from this calendar
+                                                    all_events.retain(|e| {
+                                                        if let Some(ref calendar_path) = e.calendar_path {
+                                                            calendar_path != &format!("external_{}", id)
+                                                        } else {
+                                                            true
+                                                        }
+                                                    });
+                                                    // Add new events
+                                                    all_events.extend(events);
+                                                    external_calendar_events.set(all_events);
+                                                    
+                                                    // Update the last_fetched timestamp in calendars list
+                                                    if let Ok(calendars) = CalendarService::get_external_calendars().await {
+                                                        external_calendars.set(calendars);
+                                                    }
+                                                }
+                                            });
+                                        }
+                                    })}
                                     color_picker_open={(*color_picker_open).clone()}
                                     on_color_change={on_color_change}
                                     on_color_picker_toggle={on_color_picker_toggle}
                                     available_colors={(*available_colors).clone()}
                                     on_calendar_context_menu={on_calendar_context_menu}
+                                    on_calendar_visibility_toggle={Callback::from({
+                                        let user_info = user_info.clone();
+                                        move |calendar_path: String| {
+                                            let user_info = user_info.clone();
+                                            wasm_bindgen_futures::spawn_local(async move {
+                                                if let Some(mut info) = (*user_info).clone() {
+                                                    // Toggle the visibility
+                                                    if let Some(calendar) = info.calendars.iter_mut().find(|c| c.path == calendar_path) {
+                                                        calendar.is_visible = !calendar.is_visible;
+                                                        user_info.set(Some(info));
+                                                    }
+                                                }
+                                            });
+                                        }
+                                    })}
                                     current_view={(*current_view).clone()}
                                     on_view_change={on_view_change}
                                     current_theme={(*current_theme).clone()}
@@ -941,6 +1158,8 @@ pub fn App() -> Html {
                                         auth_token={(*auth_token).clone()}
                                         user_info={(*user_info).clone()}
                                         on_login={on_login.clone()}
+                                        external_calendar_events={(*external_calendar_events).clone()}
+                                        external_calendars={(*external_calendars).clone()}
                                         on_event_context_menu={Some(on_event_context_menu.clone())}
                                         on_calendar_context_menu={Some(on_calendar_date_context_menu.clone())}
                                         view={(*current_view).clone()}
@@ -1193,6 +1412,59 @@ pub fn App() -> Html {
                     on_create={on_event_create}
                     available_calendars={user_info.as_ref().map(|ui| ui.calendars.clone()).unwrap_or_default()}
                 />
+
+                <ExternalCalendarModal
+                    is_open={*external_calendar_modal_open}
+                    on_close={Callback::from({
+                        let external_calendar_modal_open = external_calendar_modal_open.clone();
+                        move |_| external_calendar_modal_open.set(false)
+                    })}
+                    on_success={Callback::from({
+                        let external_calendars = external_calendars.clone();
+                        let external_calendar_events = external_calendar_events.clone();
+                        move |new_calendar_id: i32| {
+                            let external_calendars = external_calendars.clone();
+                            let external_calendar_events = external_calendar_events.clone();
+                            wasm_bindgen_futures::spawn_local(async move {
+                                // First, refresh the calendar list to get the new calendar
+                                match CalendarService::get_external_calendars().await {
+                                    Ok(calendars) => {
+                                        external_calendars.set(calendars.clone());
+                                        
+                                        // Then immediately fetch events for the new calendar if it's visible
+                                        if let Some(new_calendar) = calendars.iter().find(|c| c.id == new_calendar_id) {
+                                            if new_calendar.is_visible {
+                                                match CalendarService::fetch_external_calendar_events(new_calendar_id).await {
+                                                    Ok(mut events) => {
+                                                        // Set calendar_path for color matching
+                                                        for event in &mut events {
+                                                            event.calendar_path = Some(format!("external_{}", new_calendar_id));
+                                                        }
+                                                        
+                                                        // Add the new calendar's events to existing events
+                                                        let mut all_events = (*external_calendar_events).clone();
+                                                        all_events.extend(events);
+                                                        external_calendar_events.set(all_events);
+                                                    }
+                                                    Err(e) => {
+                                                        web_sys::console::log_1(
+                                                            &format!("Failed to fetch events for new calendar {}: {}", new_calendar_id, e).into(),
+                                                        );
+                                                    }
+                                                }
+                                            }
+                                        }
+                                    }
+                                    Err(err) => {
+                                        web_sys::console::log_1(
+                                            &format!("Failed to refresh calendars after creation: {}", err).into(),
+                                        );
+                                    }
+                                }
+                            });
+                        }
+                    })}
+                />
             </div>
         </BrowserRouter>
     }

frontend/src/components/calendar.rs

@@ -2,7 +2,7 @@ use crate::components::{
     CalendarHeader, CreateEventModal, EventCreationData, EventModal, MonthView, ViewMode, WeekView,
 };
 use crate::models::ical::VEvent;
-use crate::services::{calendar_service::UserInfo, CalendarService};
+use crate::services::{calendar_service::{UserInfo, ExternalCalendar}, CalendarService};
 use chrono::{Datelike, Duration, Local, NaiveDate};
 use gloo_storage::{LocalStorage, Storage};
 use std::collections::HashMap;
@@ -14,6 +14,10 @@ pub struct CalendarProps {
     #[prop_or_default]
     pub user_info: Option<UserInfo>,
     #[prop_or_default]
+    pub external_calendar_events: Vec<VEvent>,
+    #[prop_or_default]
+    pub external_calendars: Vec<ExternalCalendar>,
+    #[prop_or_default]
     pub on_event_context_menu: Option<Callback<(web_sys::MouseEvent, VEvent)>>,
     #[prop_or_default]
     pub on_calendar_context_menu: Option<Callback<(web_sys::MouseEvent, NaiveDate)>>,
@@ -101,10 +105,14 @@ pub fn Calendar(props: &CalendarProps) -> Html {
         let loading = loading.clone();
         let error = error.clone();
         let current_date = current_date.clone();
+        let external_events = props.external_calendar_events.clone(); // Clone before the effect
+        let view = props.view.clone(); // Clone before the effect
         
-        use_effect_with((*current_date, props.view.clone()), move |(date, _view)| {
+        use_effect_with((*current_date, view.clone(), external_events.len(), props.user_info.clone()), move |(date, _view, _external_len, user_info)| {
             let auth_token: Option<String> = LocalStorage::get("auth_token").ok();
             let date = *date; // Clone the date to avoid lifetime issues
+            let external_events = external_events.clone(); // Clone external events to avoid lifetime issues
+            let user_info = user_info.clone(); // Clone user_info to avoid lifetime issues
             
             if let Some(token) = auth_token {
                 let events = events.clone();
@@ -141,7 +149,38 @@ pub fn Calendar(props: &CalendarProps) -> Html {
                         .await
                     {
                         Ok(vevents) => {
-                            let grouped_events = CalendarService::group_events_by_date(vevents);
+                            // Filter CalDAV events based on calendar visibility
+                            let mut filtered_events = if let Some(user_info) = user_info.as_ref() {
+                                vevents.into_iter()
+                                    .filter(|event| {
+                                        if let Some(calendar_path) = event.calendar_path.as_ref() {
+                                            // Find the calendar info for this event
+                                            user_info.calendars.iter()
+                                                .find(|cal| &cal.path == calendar_path)
+                                                .map(|cal| cal.is_visible)
+                                                .unwrap_or(true) // Default to visible if not found
+                                        } else {
+                                            true // Show events without calendar path
+                                        }
+                                    })
+                                    .collect()
+                            } else {
+                                vevents // Show all events if no user info
+                            };
+                            
+                            // Mark external events as external by adding a special category
+                            let marked_external_events: Vec<VEvent> = external_events
+                                .into_iter()
+                                .map(|mut event| {
+                                    // Add a special category to identify external events
+                                    event.categories.push("__EXTERNAL_CALENDAR__".to_string());
+                                    event
+                                })
+                                .collect();
+                            
+                            filtered_events.extend(marked_external_events);
+                            
+                            let grouped_events = CalendarService::group_events_by_date(filtered_events);
                             events.set(grouped_events);
                             loading.set(false);
                         }
@@ -452,6 +491,7 @@ pub fn Calendar(props: &CalendarProps) -> Html {
                                 on_event_click={on_event_click.clone()}
                                 refreshing_event_uid={(*refreshing_event_uid).clone()}
                                 user_info={props.user_info.clone()}
+                                external_calendars={props.external_calendars.clone()}
                                 on_event_context_menu={props.on_event_context_menu.clone()}
                                 on_calendar_context_menu={props.on_calendar_context_menu.clone()}
                                 selected_date={Some(*selected_date)}
@@ -467,6 +507,7 @@ pub fn Calendar(props: &CalendarProps) -> Html {
                             on_event_click={on_event_click.clone()}
                             refreshing_event_uid={(*refreshing_event_uid).clone()}
                             user_info={props.user_info.clone()}
+                            external_calendars={props.external_calendars.clone()}
                             on_event_context_menu={props.on_event_context_menu.clone()}
                             on_calendar_context_menu={props.on_calendar_context_menu.clone()}
                             on_create_event={Some(on_create_event)}

frontend/src/components/calendar_list_item.rs

@@ -10,6 +10,7 @@ pub struct CalendarListItemProps {
     pub on_color_picker_toggle: Callback<String>,    // calendar_path
     pub available_colors: Vec<String>,
     pub on_context_menu: Callback<(MouseEvent, String)>, // (event, calendar_path)
+    pub on_visibility_toggle: Callback<String>,      // calendar_path
 }
 
 #[function_component(CalendarListItem)]
@@ -32,44 +33,59 @@ pub fn calendar_list_item(props: &CalendarListItemProps) -> Html {
         })
     };
 
+    let on_visibility_toggle = {
+        let cal_path = props.calendar.path.clone();
+        let on_visibility_toggle = props.on_visibility_toggle.clone();
+        Callback::from(move |_| {
+            on_visibility_toggle.emit(cal_path.clone());
+        })
+    };
+
     html! {
         <li key={props.calendar.path.clone()} oncontextmenu={on_context_menu}>
-            <span class="calendar-color"
-                  style={format!("background-color: {}", props.calendar.color)}
-                  onclick={on_color_click}>
-                {
-                    if props.color_picker_open {
-                        html! {
-                            <div class="color-picker">
-                                {
-                                    props.available_colors.iter().map(|color| {
-                                        let color_str = color.clone();
-                                        let cal_path = props.calendar.path.clone();
-                                        let on_color_change = props.on_color_change.clone();
+            <div class="calendar-info">
+                <input
+                    type="checkbox"
+                    checked={props.calendar.is_visible}
+                    onchange={on_visibility_toggle}
+                />
+                <span class="calendar-color"
+                      style={format!("background-color: {}", props.calendar.color)}
+                      onclick={on_color_click}>
+                    {
+                        if props.color_picker_open {
+                            html! {
+                                <div class="color-picker">
+                                    {
+                                        props.available_colors.iter().map(|color| {
+                                            let color_str = color.clone();
+                                            let cal_path = props.calendar.path.clone();
+                                            let on_color_change = props.on_color_change.clone();
 
-                                        let on_color_select = Callback::from(move |_: MouseEvent| {
-                                            on_color_change.emit((cal_path.clone(), color_str.clone()));
-                                        });
+                                            let on_color_select = Callback::from(move |_: MouseEvent| {
+                                                on_color_change.emit((cal_path.clone(), color_str.clone()));
+                                            });
 
-                                        let is_selected = props.calendar.color == *color;
-                                        let class_name = if is_selected { "color-option selected" } else { "color-option" };
+                                            let is_selected = props.calendar.color == *color;
+                                            let class_name = if is_selected { "color-option selected" } else { "color-option" };
 
-                                        html! {
-                                            <div class={class_name}
-                                                 style={format!("background-color: {}", color)}
-                                                 onclick={on_color_select}>
-                                            </div>
-                                        }
-                                    }).collect::<Html>()
-                                }
-                            </div>
+                                            html! {
+                                                <div class={class_name}
+                                                     style={format!("background-color: {}", color)}
+                                                     onclick={on_color_select}>
+                                                </div>
+                                            }
+                                        }).collect::<Html>()
+                                    }
+                                </div>
+                            }
+                        } else {
+                            html! {}
                         }
-                    } else {
-                        html! {}
                     }
-                }
-            </span>
-            <span class="calendar-name">{&props.calendar.display_name}</span>
+                </span>
+                <span class="calendar-name">{&props.calendar.display_name}</span>
+            </div>
         </li>
     }
 }

frontend/src/components/external_calendar_modal.rs

@@ -0,0 +1,222 @@
+use web_sys::HtmlInputElement;
+use yew::prelude::*;
+
+use crate::services::calendar_service::CalendarService;
+
+#[derive(Properties, PartialEq)]
+pub struct ExternalCalendarModalProps {
+    pub is_open: bool,
+    pub on_close: Callback<()>,
+    pub on_success: Callback<i32>, // Pass the newly created calendar ID
+}
+
+#[function_component(ExternalCalendarModal)]
+pub fn external_calendar_modal(props: &ExternalCalendarModalProps) -> Html {
+    let name_ref = use_node_ref();
+    let url_ref = use_node_ref();
+    let color_ref = use_node_ref();
+    let is_loading = use_state(|| false);
+    let error_message = use_state(|| None::<String>);
+
+    let on_submit = {
+        let name_ref = name_ref.clone();
+        let url_ref = url_ref.clone();
+        let color_ref = color_ref.clone();
+        let is_loading = is_loading.clone();
+        let error_message = error_message.clone();
+        let on_close = props.on_close.clone();
+        let on_success = props.on_success.clone();
+
+        Callback::from(move |e: SubmitEvent| {
+            e.prevent_default();
+            
+            let name = name_ref
+                .cast::<HtmlInputElement>()
+                .map(|input| input.value())
+                .unwrap_or_default()
+                .trim()
+                .to_string();
+            
+            let url = url_ref
+                .cast::<HtmlInputElement>()
+                .map(|input| input.value())
+                .unwrap_or_default()
+                .trim()
+                .to_string();
+                
+            let color = color_ref
+                .cast::<HtmlInputElement>()
+                .map(|input| input.value())
+                .unwrap_or_else(|| "#4285f4".to_string());
+
+            if name.is_empty() {
+                error_message.set(Some("Calendar name is required".to_string()));
+                return;
+            }
+
+            if url.is_empty() {
+                error_message.set(Some("Calendar URL is required".to_string()));
+                return;
+            }
+
+            // Basic URL validation
+            if !url.starts_with("http://") && !url.starts_with("https://") {
+                error_message.set(Some("Please enter a valid HTTP or HTTPS URL".to_string()));
+                return;
+            }
+
+            error_message.set(None);
+            is_loading.set(true);
+
+            let is_loading = is_loading.clone();
+            let error_message = error_message.clone();
+            let on_close = on_close.clone();
+            let on_success = on_success.clone();
+
+            wasm_bindgen_futures::spawn_local(async move {
+                match CalendarService::create_external_calendar(&name, &url, &color).await {
+                    Ok(new_calendar) => {
+                        is_loading.set(false);
+                        on_success.emit(new_calendar.id);
+                        on_close.emit(());
+                    }
+                    Err(e) => {
+                        is_loading.set(false);
+                        error_message.set(Some(format!("Failed to add calendar: {}", e)));
+                    }
+                }
+            });
+        })
+    };
+
+    let on_cancel = {
+        let on_close = props.on_close.clone();
+        Callback::from(move |_| {
+            on_close.emit(());
+        })
+    };
+    
+    let on_cancel_clone = on_cancel.clone();
+
+    if !props.is_open {
+        return html! {};
+    }
+
+    html! {
+        <div class="modal-backdrop" onclick={on_cancel_clone}>
+            <div class="external-calendar-modal" onclick={Callback::from(|e: MouseEvent| e.stop_propagation())}>
+                <div class="modal-header">
+                    <h3>{"Add External Calendar"}</h3>
+                    <button class="modal-close" onclick={on_cancel.clone()}>{"×"}</button>
+                </div>
+                
+                <form onsubmit={on_submit}>
+                    <div class="modal-body">
+                        {
+                            if let Some(error) = (*error_message).as_ref() {
+                                html! {
+                                    <div class="error-message">
+                                        {error}
+                                    </div>
+                                }
+                            } else {
+                                html! {}
+                            }
+                        }
+                        
+                        <div class="form-help" style="margin-bottom: 1.5rem; padding: 1rem; background: #f8f9fa; border-radius: 8px; border-left: 4px solid #007bff;">
+                            <h4 style="margin: 0 0 0.5rem 0; font-size: 0.9rem; color: #495057;">{"Setting up External Calendars"}</h4>
+                            <p style="margin: 0 0 0.5rem 0; font-size: 0.8rem; line-height: 1.4;">
+                                {"Currently tested with Outlook 365 and Google Calendar. To get your calendar link:"}
+                            </p>
+                            
+                            <div style="margin-bottom: 1rem;">
+                                <strong style="font-size: 0.8rem; color: #495057;">{"Outlook 365:"}</strong>
+                                <ol style="margin: 0.3rem 0 0 0; padding-left: 1.2rem; font-size: 0.8rem; line-height: 1.3;">
+                                    <li>{"Go to Outlook Settings"}</li>
+                                    <li>{"Navigate to Calendar → Shared Calendars"}</li>
+                                    <li>{"Click \"Publish a calendar\""}</li>
+                                    <li>{"Select your calendar and choose \"Can view all details\""}</li>
+                                    <li>{"Copy the ICS link and paste it below"}</li>
+                                </ol>
+                            </div>
+                            
+                            <div>
+                                <strong style="font-size: 0.8rem; color: #495057;">{"Google Calendar:"}</strong>
+                                <ol style="margin: 0.3rem 0 0 0; padding-left: 1.2rem; font-size: 0.8rem; line-height: 1.3;">
+                                    <li>{"Hover over your calendar name in the left sidebar"}</li>
+                                    <li>{"Click the three dots that appear"}</li>
+                                    <li>{"Select \"Settings and sharing\""}</li>
+                                    <li>{"Scroll to \"Integrate calendar\""}</li>
+                                    <li>{"Copy the \"Public address in iCal format\" link"}</li>
+                                </ol>
+                            </div>
+                        </div>
+                        
+                        <div class="form-group">
+                            <label for="external-calendar-name">{"Calendar Name"}</label>
+                            <input
+                                ref={name_ref}
+                                id="external-calendar-name"
+                                type="text"
+                                placeholder="My External Calendar"
+                                disabled={*is_loading}
+                                required={true}
+                            />
+                        </div>
+
+                        <div class="form-group">
+                            <label for="external-calendar-url">{"ICS URL"}</label>
+                            <input
+                                ref={url_ref}
+                                id="external-calendar-url"
+                                type="url"
+                                placeholder="https://example.com/calendar.ics"
+                                disabled={*is_loading}
+                                required={true}
+                            />
+                            <small class="form-help">
+                                {"Enter the public ICS URL for the calendar you want to add"}
+                            </small>
+                        </div>
+
+                        <div class="form-group">
+                            <label for="external-calendar-color">{"Color"}</label>
+                            <input
+                                ref={color_ref}
+                                id="external-calendar-color"
+                                type="color"
+                                value="#4285f4"
+                                disabled={*is_loading}
+                            />
+                        </div>
+                    </div>
+
+                    <div class="modal-actions">
+                        <button
+                            type="button"
+                            class="btn btn-secondary"
+                            onclick={on_cancel}
+                            disabled={*is_loading}
+                        >
+                            {"Cancel"}
+                        </button>
+                        <button
+                            type="submit"
+                            class="btn btn-primary"
+                            disabled={*is_loading}
+                        >
+                            {
+                                if *is_loading {
+                                    "Adding..."
+                                } else {
+                                    "Add Calendar"
+                                }
+                            }
+                        </button>
+                    </div>
+                </form>
+            </div>
+        </div>
+    }
+}

frontend/src/components/mod.rs

@@ -8,6 +8,7 @@ pub mod create_event_modal;
 pub mod event_context_menu;
 pub mod event_form;
 pub mod event_modal;
+pub mod external_calendar_modal;
 pub mod login;
 pub mod month_view;
 pub mod recurring_edit_modal;
@@ -26,6 +27,7 @@ pub use create_event_modal::CreateEventModal;
 pub use event_form::EventCreationData;
 pub use event_context_menu::{DeleteAction, EditAction, EventContextMenu};
 pub use event_modal::EventModal;
+pub use external_calendar_modal::ExternalCalendarModal;
 pub use login::Login;
 pub use month_view::MonthView;
 pub use recurring_edit_modal::{RecurringEditAction, RecurringEditModal};

frontend/src/components/month_view.rs

@@ -1,5 +1,5 @@
 use crate::models::ical::VEvent;
-use crate::services::calendar_service::UserInfo;
+use crate::services::calendar_service::{UserInfo, ExternalCalendar};
 use chrono::{Datelike, NaiveDate, Weekday};
 use std::collections::HashMap;
 use wasm_bindgen::{prelude::*, JsCast};
@@ -17,6 +17,8 @@ pub struct MonthViewProps {
     #[prop_or_default]
     pub user_info: Option<UserInfo>,
     #[prop_or_default]
+    pub external_calendars: Vec<ExternalCalendar>,
+    #[prop_or_default]
     pub on_event_context_menu: Option<Callback<(web_sys::MouseEvent, VEvent)>>,
     #[prop_or_default]
     pub on_calendar_context_menu: Option<Callback<(web_sys::MouseEvent, NaiveDate)>>,
@@ -85,8 +87,20 @@ pub fn month_view(props: &MonthViewProps) -> Html {
 
     // Helper function to get calendar color for an event
     let get_event_color = |event: &VEvent| -> String {
-        if let Some(user_info) = &props.user_info {
-            if let Some(calendar_path) = &event.calendar_path {
+        if let Some(calendar_path) = &event.calendar_path {
+            // Check external calendars first (path format: "external_{id}")
+            if calendar_path.starts_with("external_") {
+                if let Ok(id_str) = calendar_path.strip_prefix("external_").unwrap_or("").parse::<i32>() {
+                    if let Some(external_calendar) = props.external_calendars
+                        .iter()
+                        .find(|cal| cal.id == id_str)
+                    {
+                        return external_calendar.color.clone();
+                    }
+                }
+            }
+            // Check regular calendars
+            else if let Some(user_info) = &props.user_info {
                 if let Some(calendar) = user_info
                     .calendars
                     .iter()
@@ -194,6 +208,7 @@ pub fn month_view(props: &MonthViewProps) -> Html {
                                             <div
                                                 class={classes!("event-box", if is_refreshing { Some("refreshing") } else { None })}
                                                 style={format!("background-color: {}", event_color)}
+                                                data-external={event.categories.contains(&"__EXTERNAL_CALENDAR__".to_string()).to_string()}
                                                 {onclick}
                                                 {oncontextmenu}
                                             >

frontend/src/components/route_handler.rs

@@ -1,6 +1,6 @@
 use crate::components::{Login, ViewMode};
 use crate::models::ical::VEvent;
-use crate::services::calendar_service::UserInfo;
+use crate::services::calendar_service::{UserInfo, ExternalCalendar};
 use yew::prelude::*;
 use yew_router::prelude::*;
 
@@ -20,6 +20,10 @@ pub struct RouteHandlerProps {
     pub user_info: Option<UserInfo>,
     pub on_login: Callback<String>,
     #[prop_or_default]
+    pub external_calendar_events: Vec<VEvent>,
+    #[prop_or_default]
+    pub external_calendars: Vec<ExternalCalendar>,
+    #[prop_or_default]
     pub on_event_context_menu: Option<Callback<(web_sys::MouseEvent, VEvent)>>,
     #[prop_or_default]
     pub on_calendar_context_menu: Option<Callback<(web_sys::MouseEvent, chrono::NaiveDate)>>,
@@ -48,6 +52,8 @@ pub fn route_handler(props: &RouteHandlerProps) -> Html {
     let auth_token = props.auth_token.clone();
     let user_info = props.user_info.clone();
     let on_login = props.on_login.clone();
+    let external_calendar_events = props.external_calendar_events.clone();
+    let external_calendars = props.external_calendars.clone();
     let on_event_context_menu = props.on_event_context_menu.clone();
     let on_calendar_context_menu = props.on_calendar_context_menu.clone();
     let view = props.view.clone();
@@ -60,6 +66,8 @@ pub fn route_handler(props: &RouteHandlerProps) -> Html {
             let auth_token = auth_token.clone();
             let user_info = user_info.clone();
             let on_login = on_login.clone();
+            let external_calendar_events = external_calendar_events.clone();
+            let external_calendars = external_calendars.clone();
             let on_event_context_menu = on_event_context_menu.clone();
             let on_calendar_context_menu = on_calendar_context_menu.clone();
             let view = view.clone();
@@ -87,6 +95,8 @@ pub fn route_handler(props: &RouteHandlerProps) -> Html {
                         html! {
                             <CalendarView
                                 user_info={user_info}
+                                external_calendar_events={external_calendar_events}
+                                external_calendars={external_calendars}
                                 on_event_context_menu={on_event_context_menu}
                                 on_calendar_context_menu={on_calendar_context_menu}
                                 view={view}
@@ -108,6 +118,10 @@ pub fn route_handler(props: &RouteHandlerProps) -> Html {
 pub struct CalendarViewProps {
     pub user_info: Option<UserInfo>,
     #[prop_or_default]
+    pub external_calendar_events: Vec<VEvent>,
+    #[prop_or_default]
+    pub external_calendars: Vec<ExternalCalendar>,
+    #[prop_or_default]
     pub on_event_context_menu: Option<Callback<(web_sys::MouseEvent, VEvent)>>,
     #[prop_or_default]
     pub on_calendar_context_menu: Option<Callback<(web_sys::MouseEvent, chrono::NaiveDate)>>,
@@ -139,6 +153,8 @@ pub fn calendar_view(props: &CalendarViewProps) -> Html {
         <div class="calendar-view">
             <Calendar
                 user_info={props.user_info.clone()}
+                external_calendar_events={props.external_calendar_events.clone()}
+                external_calendars={props.external_calendars.clone()}
                 on_event_context_menu={props.on_event_context_menu.clone()}
                 on_calendar_context_menu={props.on_calendar_context_menu.clone()}
                 view={props.view.clone()}

frontend/src/components/sidebar.rs

@@ -1,5 +1,5 @@
 use crate::components::CalendarListItem;
-use crate::services::calendar_service::UserInfo;
+use crate::services::calendar_service::{UserInfo, ExternalCalendar};
 use web_sys::HtmlSelectElement;
 use yew::prelude::*;
 use yew_router::prelude::*;
@@ -101,11 +101,17 @@ pub struct SidebarProps {
     pub user_info: Option<UserInfo>,
     pub on_logout: Callback<()>,
     pub on_create_calendar: Callback<()>,
+    pub on_create_external_calendar: Callback<()>,
+    pub external_calendars: Vec<ExternalCalendar>,
+    pub on_external_calendar_toggle: Callback<i32>,
+    pub on_external_calendar_delete: Callback<i32>,
+    pub on_external_calendar_refresh: Callback<i32>,
     pub color_picker_open: Option<String>,
     pub on_color_change: Callback<(String, String)>,
     pub on_color_picker_toggle: Callback<String>,
     pub available_colors: Vec<String>,
     pub on_calendar_context_menu: Callback<(MouseEvent, String)>,
+    pub on_calendar_visibility_toggle: Callback<String>,
     pub current_view: ViewMode,
     pub on_view_change: Callback<ViewMode>,
     pub current_theme: Theme,
@@ -116,6 +122,7 @@ pub struct SidebarProps {
 
 #[function_component(Sidebar)]
 pub fn sidebar(props: &SidebarProps) -> Html {
+    let external_context_menu_open = use_state(|| None::<i32>);
     let on_view_change = {
         let on_view_change = props.on_view_change.clone();
         Callback::from(move |e: Event| {
@@ -155,6 +162,30 @@ pub fn sidebar(props: &SidebarProps) -> Html {
         })
     };
 
+    let on_external_calendar_context_menu = {
+        let external_context_menu_open = external_context_menu_open.clone();
+        Callback::from(move |(e, cal_id): (MouseEvent, i32)| {
+            e.prevent_default();
+            external_context_menu_open.set(Some(cal_id));
+        })
+    };
+
+    let on_external_calendar_delete = {
+        let on_external_calendar_delete = props.on_external_calendar_delete.clone();
+        let external_context_menu_open = external_context_menu_open.clone();
+        Callback::from(move |cal_id: i32| {
+            on_external_calendar_delete.emit(cal_id);
+            external_context_menu_open.set(None);
+        })
+    };
+
+    let close_external_context_menu = {
+        let external_context_menu_open = external_context_menu_open.clone();
+        Callback::from(move |_| {
+            external_context_menu_open.set(None);
+        })
+    };
+
     html! {
         <aside class="app-sidebar">
             <div class="sidebar-header">
@@ -192,6 +223,7 @@ pub fn sidebar(props: &SidebarProps) -> Html {
                                                     on_color_picker_toggle={props.on_color_picker_toggle.clone()}
                                                     available_colors={props.available_colors.clone()}
                                                     on_context_menu={props.on_calendar_context_menu.clone()}
+                                                    on_visibility_toggle={props.on_calendar_visibility_toggle.clone()}
                                                 />
                                             }
                                         }).collect::<Html>()
@@ -206,10 +238,127 @@ pub fn sidebar(props: &SidebarProps) -> Html {
                     html! {}
                 }
             }
+            
+            // External calendars section
+            <div class="external-calendar-list">
+                <h3>{"External Calendars"}</h3>
+                {
+                    if !props.external_calendars.is_empty() {
+                        html! {
+                            <ul class="external-calendar-items">
+                                {
+                                    props.external_calendars.iter().map(|cal| {
+                                        let on_toggle = {
+                                            let on_external_calendar_toggle = props.on_external_calendar_toggle.clone();
+                                            let cal_id = cal.id;
+                                            Callback::from(move |_| {
+                                                on_external_calendar_toggle.emit(cal_id);
+                                            })
+                                        };
+                                        
+                                        html! {
+                                            <li class="external-calendar-item" style="position: relative;">
+                                                <div 
+                                                    class="external-calendar-info"
+                                                    oncontextmenu={{
+                                                        let on_context_menu = on_external_calendar_context_menu.clone();
+                                                        let cal_id = cal.id;
+                                                        Callback::from(move |e: MouseEvent| {
+                                                            on_context_menu.emit((e, cal_id));
+                                                        })
+                                                    }}
+                                                >
+                                                    <input
+                                                        type="checkbox"
+                                                        checked={cal.is_visible}
+                                                        onchange={on_toggle}
+                                                    />
+                                                    <span 
+                                                        class="external-calendar-color" 
+                                                        style={format!("background-color: {}", cal.color)}
+                                                    />
+                                                    <span class="external-calendar-name">{&cal.name}</span>
+                                                    <div class="external-calendar-actions">
+                                                        {
+                                                            if let Some(last_fetched) = cal.last_fetched {
+                                                                let local_time = last_fetched.with_timezone(&chrono::Local);
+                                                                html! {
+                                                                    <span class="last-updated" title={format!("Last updated: {}", local_time.format("%Y-%m-%d %H:%M"))}>
+                                                                        {format!("{}", local_time.format("%H:%M"))}
+                                                                    </span>
+                                                                }
+                                                            } else {
+                                                                html! {
+                                                                    <span class="last-updated">{"Never"}</span>
+                                                                }
+                                                            }
+                                                        }
+                                                        <button 
+                                                            class="external-calendar-refresh-btn" 
+                                                            title="Refresh calendar"
+                                                            onclick={{
+                                                                let on_refresh = props.on_external_calendar_refresh.clone();
+                                                                let cal_id = cal.id;
+                                                                Callback::from(move |e: MouseEvent| {
+                                                                    e.stop_propagation();
+                                                                    on_refresh.emit(cal_id);
+                                                                })
+                                                            }}
+                                                        >
+                                                            {"🔄"}
+                                                        </button>
+                                                    </div>
+                                                </div>
+                                                {
+                                                    if *external_context_menu_open == Some(cal.id) {
+                                                        html! {
+                                                            <>
+                                                                <div 
+                                                                    class="context-menu-overlay" 
+                                                                    onclick={close_external_context_menu.clone()}
+                                                                    style="position: fixed; top: 0; left: 0; width: 100vw; height: 100vh; z-index: 999;"
+                                                                />
+                                                                <div class="context-menu" style="position: absolute; top: 0; right: 0; background: white; border: 1px solid #ccc; border-radius: 4px; box-shadow: 0 2px 8px rgba(0,0,0,0.15); z-index: 1000; min-width: 120px;">
+                                                                    <div 
+                                                                        class="context-menu-item" 
+                                                                        style="padding: 8px 12px; cursor: pointer; color: #d73a49;"
+                                                                        onclick={{
+                                                                            let on_delete = on_external_calendar_delete.clone();
+                                                                            let cal_id = cal.id;
+                                                                            Callback::from(move |_| {
+                                                                                on_delete.emit(cal_id);
+                                                                            })
+                                                                        }}
+                                                                    >
+                                                                        {"Delete Calendar"}
+                                                                    </div>
+                                                                </div>
+                                                            </>
+                                                        }
+                                                    } else {
+                                                        html! {}
+                                                    }
+                                                }
+                                            </li>
+                                        }
+                                    }).collect::<Html>()
+                                }
+                            </ul>
+                        }
+                    } else {
+                        html! {}
+                    }
+                }
+            </div>
+            
             <div class="sidebar-footer">
                 <button onclick={props.on_create_calendar.reform(|_| ())} class="create-calendar-button">
                     {"+ Create Calendar"}
                 </button>
+                
+                <button onclick={props.on_create_external_calendar.reform(|_| ())} class="create-external-calendar-button">
+                    {"+ Add External Calendar"}
+                </button>
 
                 <div class="view-selector">
                     <select class="view-selector-dropdown" onchange={on_view_change}>

frontend/src/components/week_view.rs

@@ -1,6 +1,6 @@
 use crate::components::{EventCreationData, RecurringEditAction, RecurringEditModal};
 use crate::models::ical::VEvent;
-use crate::services::calendar_service::UserInfo;
+use crate::services::calendar_service::{UserInfo, ExternalCalendar};
 use chrono::{Datelike, Duration, Local, NaiveDate, NaiveDateTime, NaiveTime, Timelike, Weekday};
 use std::collections::HashMap;
 use web_sys::MouseEvent;
@@ -17,6 +17,8 @@ pub struct WeekViewProps {
     #[prop_or_default]
     pub user_info: Option<UserInfo>,
     #[prop_or_default]
+    pub external_calendars: Vec<ExternalCalendar>,
+    #[prop_or_default]
     pub on_event_context_menu: Option<Callback<(web_sys::MouseEvent, VEvent)>>,
     #[prop_or_default]
     pub on_calendar_context_menu: Option<Callback<(web_sys::MouseEvent, NaiveDate)>>,
@@ -81,8 +83,20 @@ pub fn week_view(props: &WeekViewProps) -> Html {
 
     // Helper function to get calendar color for an event
     let get_event_color = |event: &VEvent| -> String {
-        if let Some(user_info) = &props.user_info {
-            if let Some(calendar_path) = &event.calendar_path {
+        if let Some(calendar_path) = &event.calendar_path {
+            // Check external calendars first (path format: "external_{id}")
+            if calendar_path.starts_with("external_") {
+                if let Ok(id_str) = calendar_path.strip_prefix("external_").unwrap_or("").parse::<i32>() {
+                    if let Some(external_calendar) = props.external_calendars
+                        .iter()
+                        .find(|cal| cal.id == id_str)
+                    {
+                        return external_calendar.color.clone();
+                    }
+                }
+            }
+            // Check regular calendars
+            else if let Some(user_info) = &props.user_info {
                 if let Some(calendar) = user_info
                     .calendars
                     .iter()
@@ -371,6 +385,7 @@ pub fn week_view(props: &WeekViewProps) -> Html {
                                                         <div 
                                                             class="all-day-event"
                                                             style={format!("background-color: {}", event_color)}
+                                                            data-external={event.categories.contains(&"__EXTERNAL_CALENDAR__".to_string()).to_string()}
                                                             {onclick}
                                                             {oncontextmenu}
                                                         >
@@ -905,6 +920,7 @@ pub fn week_view(props: &WeekViewProps) -> Html {
                                                                         column_width
                                                                     )
                                                                 }
+                                                                data-external={event.categories.contains(&"__EXTERNAL_CALENDAR__".to_string()).to_string()}
                                                                 {onclick}
                                                                 {oncontextmenu}
                                                                 onmousedown={onmousedown_event}
@@ -992,6 +1008,7 @@ pub fn week_view(props: &WeekViewProps) -> Html {
                                                                 <div
                                                                     class="temp-event-box moving-event"
                                                                     style={format!("top: {}px; height: {}px; background-color: {}; opacity: 0.7;", preview_position, duration_pixels, event_color)}
+                                                                    data-external={event.categories.contains(&"__EXTERNAL_CALENDAR__".to_string()).to_string()}
                                                                 >
                                                                     <div class="event-title">{event.summary.as_ref().unwrap_or(&"Untitled".to_string())}</div>
                                                                     {if duration_pixels > 30.0 {
@@ -1025,6 +1042,7 @@ pub fn week_view(props: &WeekViewProps) -> Html {
                                                                 <div
                                                                     class="temp-event-box resizing-event"
                                                                     style={format!("top: {}px; height: {}px; background-color: {}; opacity: 0.7;", new_start_pixels, new_height, event_color)}
+                                                                    data-external={event.categories.contains(&"__EXTERNAL_CALENDAR__".to_string()).to_string()}
                                                                 >
                                                                     <div class="event-title">{event.summary.as_ref().unwrap_or(&"Untitled".to_string())}</div>
                                                                     {if new_height > 30.0 {
@@ -1052,6 +1070,7 @@ pub fn week_view(props: &WeekViewProps) -> Html {
                                                                 <div
                                                                     class="temp-event-box resizing-event"
                                                                     style={format!("top: {}px; height: {}px; background-color: {}; opacity: 0.7;", original_start_pixels, new_height, event_color)}
+                                                                    data-external={event.categories.contains(&"__EXTERNAL_CALENDAR__".to_string()).to_string()}
                                                                 >
                                                                     <div class="event-title">{event.summary.as_ref().unwrap_or(&"Untitled".to_string())}</div>
                                                                     {if new_height > 30.0 {

frontend/src/services/calendar_service.rs

@@ -1,4 +1,5 @@
 use chrono::{DateTime, Datelike, Duration, NaiveDate, TimeZone, Utc, Weekday};
+use gloo_storage::{LocalStorage, Storage};
 use serde::{Deserialize, Serialize};
 use std::collections::HashMap;
 use wasm_bindgen::JsCast;
@@ -43,6 +44,7 @@ pub struct CalendarInfo {
     pub path: String,
     pub display_name: String,
     pub color: String,
+    pub is_visible: bool,
 }
 
 // CalendarEvent, EventStatus, and EventClass are now imported from shared library
@@ -1854,4 +1856,257 @@ impl CalendarService {
 
         None
     }
+
+    // ==================== EXTERNAL CALENDAR METHODS ====================
+
+    pub async fn get_external_calendars() -> Result<Vec<ExternalCalendar>, String> {
+        let token = LocalStorage::get::<String>("auth_token")
+            .map_err(|_| "No authentication token found".to_string())?;
+
+        let window = web_sys::window().ok_or("No global window exists")?;
+
+        let opts = RequestInit::new();
+        opts.set_method("GET");
+        opts.set_mode(RequestMode::Cors);
+
+        let service = Self::new();
+        let url = format!("{}/external-calendars", service.base_url);
+        let request = Request::new_with_str_and_init(&url, &opts)
+            .map_err(|e| format!("Request creation failed: {:?}", e))?;
+
+        request
+            .headers()
+            .set("Authorization", &format!("Bearer {}", token))
+            .map_err(|e| format!("Authorization header setting failed: {:?}", e))?;
+
+        let resp_value = JsFuture::from(window.fetch_with_request(&request))
+            .await
+            .map_err(|e| format!("Request failed: {:?}", e))?;
+
+        let resp: Response = resp_value
+            .dyn_into()
+            .map_err(|e| format!("Response casting failed: {:?}", e))?;
+
+        if !resp.ok() {
+            return Err(format!("HTTP error: {}", resp.status()));
+        }
+
+        let json = JsFuture::from(resp.json().unwrap())
+            .await
+            .map_err(|e| format!("JSON parsing failed: {:?}", e))?;
+
+        let external_calendars: Vec<ExternalCalendar> = serde_wasm_bindgen::from_value(json)
+            .map_err(|e| format!("Deserialization failed: {:?}", e))?;
+
+        Ok(external_calendars)
+    }
+
+    pub async fn create_external_calendar(name: &str, url: &str, color: &str) -> Result<ExternalCalendar, String> {
+        let token = LocalStorage::get::<String>("auth_token")
+            .map_err(|_| "No authentication token found".to_string())?;
+
+        let window = web_sys::window().ok_or("No global window exists")?;
+
+        let opts = RequestInit::new();
+        opts.set_method("POST");
+        opts.set_mode(RequestMode::Cors);
+
+        let body = serde_json::json!({
+            "name": name,
+            "url": url,
+            "color": color
+        });
+
+        let service = Self::new();
+        let body_string = serde_json::to_string(&body)
+            .map_err(|e| format!("JSON serialization failed: {}", e))?;
+        opts.set_body(&body_string.into());
+
+        let url = format!("{}/external-calendars", service.base_url);
+        let request = Request::new_with_str_and_init(&url, &opts)
+            .map_err(|e| format!("Request creation failed: {:?}", e))?;
+
+        request
+            .headers()
+            .set("Authorization", &format!("Bearer {}", token))
+            .map_err(|e| format!("Authorization header setting failed: {:?}", e))?;
+
+        request
+            .headers()
+            .set("Content-Type", "application/json")
+            .map_err(|e| format!("Content-Type header setting failed: {:?}", e))?;
+
+        let resp_value = JsFuture::from(window.fetch_with_request(&request))
+            .await
+            .map_err(|e| format!("Request failed: {:?}", e))?;
+
+        let resp: Response = resp_value
+            .dyn_into()
+            .map_err(|e| format!("Response casting failed: {:?}", e))?;
+
+        if !resp.ok() {
+            return Err(format!("HTTP error: {}", resp.status()));
+        }
+
+        let json = JsFuture::from(resp.json().unwrap())
+            .await
+            .map_err(|e| format!("JSON parsing failed: {:?}", e))?;
+
+        let external_calendar: ExternalCalendar = serde_wasm_bindgen::from_value(json)
+            .map_err(|e| format!("Deserialization failed: {:?}", e))?;
+
+        Ok(external_calendar)
+    }
+
+    pub async fn update_external_calendar(
+        id: i32,
+        name: &str,
+        url: &str,
+        color: &str,
+        is_visible: bool,
+    ) -> Result<(), String> {
+        let token = LocalStorage::get::<String>("auth_token")
+            .map_err(|_| "No authentication token found".to_string())?;
+
+        let window = web_sys::window().ok_or("No global window exists")?;
+
+        let opts = RequestInit::new();
+        opts.set_method("POST");
+        opts.set_mode(RequestMode::Cors);
+
+        let body = serde_json::json!({
+            "name": name,
+            "url": url,
+            "color": color,
+            "is_visible": is_visible
+        });
+
+        let service = Self::new();
+        let body_string = serde_json::to_string(&body)
+            .map_err(|e| format!("JSON serialization failed: {}", e))?;
+        opts.set_body(&body_string.into());
+
+        let url = format!("{}/external-calendars/{}", service.base_url, id);
+        let request = Request::new_with_str_and_init(&url, &opts)
+            .map_err(|e| format!("Request creation failed: {:?}", e))?;
+
+        request
+            .headers()
+            .set("Authorization", &format!("Bearer {}", token))
+            .map_err(|e| format!("Authorization header setting failed: {:?}", e))?;
+
+        request
+            .headers()
+            .set("Content-Type", "application/json")
+            .map_err(|e| format!("Content-Type header setting failed: {:?}", e))?;
+
+        let resp_value = JsFuture::from(window.fetch_with_request(&request))
+            .await
+            .map_err(|e| format!("Request failed: {:?}", e))?;
+
+        let resp: Response = resp_value
+            .dyn_into()
+            .map_err(|e| format!("Response casting failed: {:?}", e))?;
+
+        if !resp.ok() {
+            return Err(format!("HTTP error: {}", resp.status()));
+        }
+
+        Ok(())
+    }
+
+    pub async fn delete_external_calendar(id: i32) -> Result<(), String> {
+        let token = LocalStorage::get::<String>("auth_token")
+            .map_err(|_| "No authentication token found".to_string())?;
+
+        let window = web_sys::window().ok_or("No global window exists")?;
+
+        let opts = RequestInit::new();
+        opts.set_method("DELETE");
+        opts.set_mode(RequestMode::Cors);
+
+        let service = Self::new();
+        let url = format!("{}/external-calendars/{}", service.base_url, id);
+        let request = Request::new_with_str_and_init(&url, &opts)
+            .map_err(|e| format!("Request creation failed: {:?}", e))?;
+
+        request
+            .headers()
+            .set("Authorization", &format!("Bearer {}", token))
+            .map_err(|e| format!("Authorization header setting failed: {:?}", e))?;
+
+        let resp_value = JsFuture::from(window.fetch_with_request(&request))
+            .await
+            .map_err(|e| format!("Request failed: {:?}", e))?;
+
+        let resp: Response = resp_value
+            .dyn_into()
+            .map_err(|e| format!("Response casting failed: {:?}", e))?;
+
+        if !resp.ok() {
+            return Err(format!("HTTP error: {}", resp.status()));
+        }
+
+        Ok(())
+    }
+
+    pub async fn fetch_external_calendar_events(id: i32) -> Result<Vec<VEvent>, String> {
+        let token = LocalStorage::get::<String>("auth_token")
+            .map_err(|_| "No authentication token found".to_string())?;
+
+        let window = web_sys::window().ok_or("No global window exists")?;
+
+        let opts = RequestInit::new();
+        opts.set_method("GET");
+        opts.set_mode(RequestMode::Cors);
+
+        let service = Self::new();
+        let url = format!("{}/external-calendars/{}/events", service.base_url, id);
+        let request = Request::new_with_str_and_init(&url, &opts)
+            .map_err(|e| format!("Request creation failed: {:?}", e))?;
+
+        request
+            .headers()
+            .set("Authorization", &format!("Bearer {}", token))
+            .map_err(|e| format!("Authorization header setting failed: {:?}", e))?;
+
+        let resp_value = JsFuture::from(window.fetch_with_request(&request))
+            .await
+            .map_err(|e| format!("Request failed: {:?}", e))?;
+
+        let resp: Response = resp_value
+            .dyn_into()
+            .map_err(|e| format!("Response casting failed: {:?}", e))?;
+
+        if !resp.ok() {
+            return Err(format!("HTTP error: {}", resp.status()));
+        }
+
+        let json = JsFuture::from(resp.json().unwrap())
+            .await
+            .map_err(|e| format!("JSON parsing failed: {:?}", e))?;
+
+        #[derive(Deserialize)]
+        struct ExternalCalendarEventsResponse {
+            events: Vec<VEvent>,
+            last_fetched: chrono::DateTime<chrono::Utc>,
+        }
+
+        let response: ExternalCalendarEventsResponse = serde_wasm_bindgen::from_value(json)
+            .map_err(|e| format!("Deserialization failed: {:?}", e))?;
+
+        Ok(response.events)
+    }
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+pub struct ExternalCalendar {
+    pub id: i32,
+    pub name: String,
+    pub url: String,
+    pub color: String,
+    pub is_visible: bool,
+    pub created_at: chrono::DateTime<chrono::Utc>,
+    pub updated_at: chrono::DateTime<chrono::Utc>,
+    pub last_fetched: Option<chrono::DateTime<chrono::Utc>>,
 }

frontend/styles.css

@@ -3745,3 +3745,383 @@ body {
         grid-template-columns: repeat(2, 1fr);
     }
 }
+
+/* ==================== EXTERNAL CALENDARS STYLES ==================== */
+
+/* External Calendar Section in Sidebar */
+.external-calendar-list {
+    margin-bottom: 2rem;
+}
+
+.external-calendar-list h3 {
+    color: rgba(255, 255, 255, 0.9);
+    font-size: 0.9rem;
+    font-weight: 600;
+    margin-bottom: 1rem;
+    text-transform: uppercase;
+    letter-spacing: 0.5px;
+    padding-left: 0.5rem;
+}
+
+.external-calendar-items {
+    list-style: none;
+    margin: 0;
+    padding: 0;
+}
+
+.external-calendar-item {
+    margin-bottom: 0.5rem;
+}
+
+.external-calendar-info {
+    display: flex;
+    align-items: center;
+    gap: 0.75rem;
+    padding: 0.75rem;
+    border-radius: 8px;
+    transition: all 0.2s ease;
+    cursor: pointer;
+    background: rgba(255, 255, 255, 0.05);
+    border: 1px solid rgba(255, 255, 255, 0.1);
+}
+
+.external-calendar-info:hover {
+    background: rgba(255, 255, 255, 0.1);
+    border-color: rgba(255, 255, 255, 0.2);
+    transform: translateX(2px);
+}
+
+.external-calendar-info input[type="checkbox"] {
+    width: 16px;
+    height: 16px;
+    accent-color: rgba(255, 255, 255, 0.8);
+    cursor: pointer;
+}
+
+.external-calendar-color {
+    width: 12px;
+    height: 12px;
+    border-radius: 50%;
+    border: 1px solid rgba(255, 255, 255, 0.3);
+    flex-shrink: 0;
+}
+
+.external-calendar-name {
+    color: rgba(255, 255, 255, 0.9);
+    font-size: 0.85rem;
+    font-weight: 500;
+    flex: 1;
+    overflow: hidden;
+    text-overflow: ellipsis;
+    white-space: nowrap;
+}
+
+.external-calendar-actions {
+    display: flex;
+    align-items: center;
+    gap: 0.5rem;
+    flex-shrink: 0;
+}
+
+.last-updated {
+    font-size: 0.7rem;
+    color: rgba(255, 255, 255, 0.6);
+    opacity: 0.8;
+}
+
+.external-calendar-refresh-btn {
+    background: none;
+    border: none;
+    color: rgba(255, 255, 255, 0.7);
+    cursor: pointer;
+    font-size: 0.8rem;
+    padding: 2px 4px;
+    border-radius: 3px;
+    transition: all 0.2s ease;
+    line-height: 1;
+}
+
+.external-calendar-refresh-btn:hover {
+    color: rgba(255, 255, 255, 0.9);
+    background: rgba(255, 255, 255, 0.1);
+    transform: rotate(180deg);
+}
+
+.external-calendar-indicator {
+    font-size: 0.8rem;
+    opacity: 0.7;
+    flex-shrink: 0;
+}
+
+/* CalDAV Calendar Styles */
+.calendar-info {
+    display: flex;
+    align-items: center;
+    gap: 0.75rem;
+    padding: 0.75rem;
+    border-radius: 8px;
+    transition: all 0.2s ease;
+    cursor: pointer;
+}
+
+.calendar-info:hover {
+    background: rgba(255, 255, 255, 0.1);
+    transform: translateX(2px);
+}
+
+.calendar-info input[type="checkbox"] {
+    width: 16px;
+    height: 16px;
+    accent-color: rgba(255, 255, 255, 0.8);
+    cursor: pointer;
+}
+
+/* Create External Calendar Button */
+.create-external-calendar-button {
+    background: rgba(255, 255, 255, 0.15);
+    border: 1px solid rgba(255, 255, 255, 0.25);
+    color: rgba(255, 255, 255, 0.9);
+    padding: 0.75rem 1rem;
+    border-radius: 8px;
+    cursor: pointer;
+    transition: all 0.2s ease;
+    margin-bottom: 1rem;
+    font-size: 0.85rem;
+    font-weight: 500;
+    backdrop-filter: blur(10px);
+    width: 100%;
+    position: relative;
+}
+
+.create-external-calendar-button::before {
+    content: "";
+    position: absolute;
+    left: 1rem;
+    font-size: 0.8rem;
+    opacity: 0.8;
+}
+
+.create-external-calendar-button {
+    padding-left: 2.5rem;
+}
+
+.create-external-calendar-button:hover {
+    background: rgba(255, 255, 255, 0.25);
+    border-color: rgba(255, 255, 255, 0.4);
+    transform: translateY(-1px);
+}
+
+.create-external-calendar-button:active {
+    transform: translateY(0);
+}
+
+/* External Calendar Modal */
+.external-calendar-modal {
+    background: white;
+    border-radius: 12px;
+    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
+    max-width: 500px;
+    width: 100%;
+    max-height: 90vh;
+    overflow-y: auto;
+    animation: modalSlideIn 0.3s ease;
+}
+
+.external-calendar-modal .modal-header {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    padding: 2rem 2rem 1rem;
+    border-bottom: 1px solid #e9ecef;
+}
+
+.external-calendar-modal .modal-header h3 {
+    margin: 0;
+    color: #495057;
+    font-size: 1.5rem;
+    font-weight: 600;
+    display: flex;
+    align-items: center;
+    gap: 0.5rem;
+}
+
+.external-calendar-modal .modal-header h3::before {
+    content: "📅";
+    font-size: 1.2rem;
+    opacity: 0.8;
+}
+
+.external-calendar-modal .modal-close {
+    background: none;
+    border: none;
+    font-size: 1.5rem;
+    color: #6c757d;
+    cursor: pointer;
+    padding: 0.5rem;
+    border-radius: 50%;
+    width: 2.5rem;
+    height: 2.5rem;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    transition: all 0.2s ease;
+}
+
+.external-calendar-modal .modal-close:hover {
+    background: #f8f9fa;
+    color: #495057;
+}
+
+.external-calendar-modal .modal-body {
+    padding: 1.5rem 2rem 2rem;
+}
+
+.external-calendar-modal .form-group {
+    margin-bottom: 1.5rem;
+}
+
+.external-calendar-modal .form-group label {
+    display: block;
+    margin-bottom: 0.5rem;
+    font-weight: 600;
+    color: #495057;
+    font-size: 0.9rem;
+}
+
+.external-calendar-modal .form-group input[type="text"],
+.external-calendar-modal .form-group input[type="url"] {
+    width: 100%;
+    padding: 0.75rem;
+    border: 1px solid #ced4da;
+    border-radius: 8px;
+    font-size: 0.9rem;
+    transition: all 0.2s ease;
+    background: white;
+}
+
+.external-calendar-modal .form-group input[type="text"]:focus,
+.external-calendar-modal .form-group input[type="url"]:focus {
+    outline: none;
+    border-color: var(--primary-color, #667eea);
+    box-shadow: 0 0 0 2px rgba(102, 126, 234, 0.1);
+}
+
+.external-calendar-modal .form-group input[type="color"] {
+    width: 80px;
+    height: 40px;
+    padding: 0;
+    border: 1px solid #ced4da;
+    border-radius: 8px;
+    cursor: pointer;
+    background: none;
+}
+
+.external-calendar-modal .form-help {
+    display: block;
+    margin-top: 0.5rem;
+    font-size: 0.8rem;
+    color: #6c757d;
+    font-style: italic;
+}
+
+.external-calendar-modal .modal-actions {
+    display: flex;
+    gap: 1rem;
+    justify-content: flex-end;
+    padding: 1.5rem 2rem;
+    border-top: 1px solid #e9ecef;
+    background: #f8f9fa;
+    border-radius: 0 0 12px 12px;
+}
+
+.external-calendar-modal .btn {
+    padding: 0.75rem 1.5rem;
+    border-radius: 8px;
+    font-size: 0.9rem;
+    font-weight: 600;
+    cursor: pointer;
+    transition: all 0.2s ease;
+    border: none;
+    min-width: 100px;
+}
+
+.external-calendar-modal .btn-secondary {
+    background: #6c757d;
+    color: white;
+}
+
+.external-calendar-modal .btn-secondary:hover:not(:disabled) {
+    background: #5a6268;
+    transform: translateY(-1px);
+}
+
+.external-calendar-modal .btn-primary {
+    background: var(--primary-gradient, linear-gradient(135deg, #667eea 0%, #764ba2 100%));
+    color: white;
+}
+
+.external-calendar-modal .btn-primary:hover:not(:disabled) {
+    filter: brightness(1.1);
+    transform: translateY(-1px);
+}
+
+.external-calendar-modal .btn:disabled {
+    opacity: 0.6;
+    cursor: not-allowed;
+}
+
+.external-calendar-modal .error-message {
+    background: #f8d7da;
+    color: #721c24;
+    padding: 0.75rem 1rem;
+    border-radius: 8px;
+    margin-bottom: 1rem;
+    font-size: 0.9rem;
+    border: 1px solid #f5c6cb;
+}
+
+/* External Calendar Events (Visual Distinction) */
+.event[data-external="true"] {
+    position: relative;
+    border-style: dashed !important;
+    opacity: 0.85;
+}
+
+.event[data-external="true"]::before {
+    content: "📅";
+    position: absolute;
+    top: 2px;
+    right: 2px;
+    font-size: 0.7rem;
+    opacity: 0.7;
+    z-index: 1;
+}
+
+/* Mobile Responsive */
+@media (max-width: 768px) {
+    .external-calendar-modal {
+        max-height: 95vh;
+        margin: 1rem;
+        width: calc(100% - 2rem);
+    }
+    
+    .external-calendar-modal .modal-header,
+    .external-calendar-modal .modal-body,
+    .external-calendar-modal .modal-actions {
+        padding-left: 1.5rem;
+        padding-right: 1.5rem;
+    }
+    
+    .external-calendar-info {
+        padding: 0.5rem;
+    }
+    
+    .external-calendar-name {
+        font-size: 0.8rem;
+    }
+    
+    .create-external-calendar-button {
+        font-size: 0.8rem;
+        padding: 0.5rem 1rem 0.5rem 2rem;
+    }
+}