update

Reviewed-on: #5

backend/pyproject.toml

@@ -12,6 +12,7 @@ dependencies = [
     "psycopg2-binary>=2.9.0",
     "httpx>=0.28.0",
     "icalendar>=6.0.0",
+    "recurring-ical-events>=3.0.0",
     "python-dateutil>=2.9.0",
     "pydantic[email]>=2.10.0",
     "pydantic-settings>=2.6.0",

backend/src/app/ics_service.py

@@ -1,7 +1,8 @@
 import logging
-from datetime import datetime, timezone
+from datetime import datetime, timedelta, timezone
 
 import httpx
+import recurring_ical_events
 from icalendar import Calendar
 from sqlalchemy import delete
 from sqlalchemy.ext.asyncio import AsyncSession
@@ -10,6 +11,9 @@ from app.models import BusyBlock, Participant
 
 logger = logging.getLogger(__name__)
 
+# How far into the future to expand recurring events
+RECURRING_EVENT_HORIZON_WEEKS = 8
+
 
 async def fetch_ics_content(url: str) -> str:
     async with httpx.AsyncClient(timeout=30.0) as client:
@@ -24,35 +28,48 @@ def parse_ics_to_busy_blocks(
     calendar = Calendar.from_ical(ics_content)
     blocks = []
 
-    for component in calendar.walk():
-        if component.name == "VEVENT":
-            dtstart = component.get("dtstart")
-            dtend = component.get("dtend")
+    # Define the time range for expanding recurring events
+    now = datetime.now(timezone.utc)
+    start_range = now - timedelta(days=7)  # Include recent past
+    end_range = now + timedelta(weeks=RECURRING_EVENT_HORIZON_WEEKS)
 
-            if dtstart is None or dtend is None:
-                continue
+    # Use recurring_ical_events to expand recurring events
+    events = recurring_ical_events.of(calendar).between(start_range, end_range)
 
-            start_dt = dtstart.dt
-            end_dt = dtend.dt
+    for event in events:
+        dtstart = event.get("dtstart")
+        dtend = event.get("dtend")
 
-            if not isinstance(start_dt, datetime):
-                start_dt = datetime.combine(start_dt, datetime.min.time())
-            if not isinstance(end_dt, datetime):
-                end_dt = datetime.combine(end_dt, datetime.min.time())
+        if dtstart is None:
+            continue
 
-            if start_dt.tzinfo is None:
-                start_dt = start_dt.replace(tzinfo=timezone.utc)
-            if end_dt.tzinfo is None:
-                end_dt = end_dt.replace(tzinfo=timezone.utc)
+        start_dt = dtstart.dt
+        end_dt = dtend.dt if dtend else None
 
-            blocks.append(
-                BusyBlock(
-                    participant_id=participant_id,
-                    start_time=start_dt,
-                    end_time=end_dt,
-                )
+        # Handle all-day events (date instead of datetime)
+        if not isinstance(start_dt, datetime):
+            start_dt = datetime.combine(start_dt, datetime.min.time())
+        if end_dt is None:
+            # If no end time, assume 1 hour duration
+            end_dt = start_dt + timedelta(hours=1)
+        elif not isinstance(end_dt, datetime):
+            end_dt = datetime.combine(end_dt, datetime.min.time())
+
+        # Ensure timezone awareness
+        if start_dt.tzinfo is None:
+            start_dt = start_dt.replace(tzinfo=timezone.utc)
+        if end_dt.tzinfo is None:
+            end_dt = end_dt.replace(tzinfo=timezone.utc)
+
+        blocks.append(
+            BusyBlock(
+                participant_id=participant_id,
+                start_time=start_dt,
+                end_time=end_dt,
             )
+        )
 
+    logger.info(f"Parsed {len(blocks)} events (including recurring) for participant {participant_id}")
     return blocks
 
 

backend/src/app/main.py

@@ -7,10 +7,10 @@ from fastapi.middleware.cors import CORSMiddleware
 from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from app.availability_service import calculate_availability
+from app.availability_service import calculate_availability, get_busy_blocks_for_participants, is_participant_free
 from app.database import get_db
 from app.ics_service import sync_all_calendars, sync_participant_calendar
-from app.models import Participant
+from app.models import Participant, BusyBlock
 from app.schemas import (
     AvailabilityRequest,
     AvailabilityResponse,
@@ -144,7 +144,8 @@ async def delete_participant(participant_id: UUID, db: AsyncSession = Depends(ge
 async def get_availability(
     request: AvailabilityRequest, db: AsyncSession = Depends(get_db)
 ):
-    slots = await calculate_availability(db, request.participant_ids)
+    reference_date = datetime.now(timezone.utc) + timedelta(weeks=request.week_offset)
+    slots = await calculate_availability(db, request.participant_ids, reference_date)
     return {"slots": slots}
 
 
@@ -174,6 +175,15 @@ async def sync_participant(participant_id: UUID, db: AsyncSession = Depends(get_
         raise HTTPException(status_code=500, detail=str(e))
 
 
+@app.delete("/api/bookings")
+async def clear_all_bookings(db: AsyncSession = Depends(get_db)):
+    """Clear all busy blocks (scheduled meetings) from the database."""
+    from sqlalchemy import delete
+    await db.execute(delete(BusyBlock))
+    await db.commit()
+    return {"status": "success", "message": "All bookings cleared"}
+
+
 @app.post("/api/schedule")
 async def schedule_meeting(
     data: ScheduleRequest, db: AsyncSession = Depends(get_db)
@@ -181,7 +191,7 @@ async def schedule_meeting(
     min_start_time = datetime.now(timezone.utc) + timedelta(hours=2)
     if data.start_time.replace(tzinfo=timezone.utc) < min_start_time:
         raise HTTPException(
-            status_code=400, 
+            status_code=400,
             detail="Meetings must be scheduled at least 2 hours in advance."
         )
 
@@ -189,10 +199,29 @@ async def schedule_meeting(
         select(Participant).where(Participant.id.in_(data.participant_ids))
     )
     participants = result.scalars().all()
-    
+
     if len(participants) != len(data.participant_ids):
         raise HTTPException(status_code=400, detail="Some participants not found")
 
+    # Check if all participants are actually free at the requested time
+    start_time = data.start_time.replace(tzinfo=timezone.utc) if data.start_time.tzinfo is None else data.start_time
+    end_time = data.end_time.replace(tzinfo=timezone.utc) if data.end_time.tzinfo is None else data.end_time
+
+    busy_map = await get_busy_blocks_for_participants(
+        db, data.participant_ids, start_time, end_time
+    )
+
+    busy_participants = []
+    for participant in participants:
+        if not is_participant_free(busy_map.get(participant.id, []), start_time, end_time):
+            busy_participants.append(participant.name)
+
+    if busy_participants:
+        raise HTTPException(
+            status_code=409,
+            detail=f"Cannot schedule: {', '.join(busy_participants)} {'is' if len(busy_participants) == 1 else 'are'} not available at this time. Please refresh availability and try again."
+        )
+
     participant_dicts = [
         {"name": p.name, "email": p.email} for p in participants
     ]
@@ -212,6 +241,16 @@ async def schedule_meeting(
         participant_dicts
     )
 
+    # Create busy blocks for all participants so the slot shows as taken immediately
+    for participant in participants:
+        busy_block = BusyBlock(
+            participant_id=participant.id,
+            start_time=start_time,
+            end_time=end_time,
+        )
+        db.add(busy_block)
+    await db.commit()
+
     return {
         "status": "success",
         "email_sent": email_success,

backend/src/app/schemas.py

@@ -39,6 +39,7 @@ class TimeSlot(BaseModel):
 
 class AvailabilityRequest(BaseModel):
     participant_ids: list[UUID]
+    week_offset: int = 0
 
 
 class AvailabilityResponse(BaseModel):

frontend/src/api/client.ts

@@ -71,11 +71,11 @@ export async function deleteParticipant(id: string): Promise<void> {
   }
 }
 
-export async function fetchAvailability(participantIds: string[]): Promise<TimeSlotAPI[]> {
+export async function fetchAvailability(participantIds: string[], weekOffset: number = 0): Promise<TimeSlotAPI[]> {
   const response = await fetch(`${API_URL}/api/availability`, {
     method: 'POST',
     headers: { 'Content-Type': 'application/json' },
-    body: JSON.stringify({ participant_ids: participantIds }),
+    body: JSON.stringify({ participant_ids: participantIds, week_offset: weekOffset }),
   });
   const data = await handleResponse<{ slots: TimeSlotAPI[] }>(response);
   return data.slots;
@@ -115,3 +115,10 @@ export async function scheduleMeeting(
   });
   return handleResponse(response);
 }
+
+export async function clearAllBookings(): Promise<void> {
+  const response = await fetch(`${API_URL}/api/bookings`, { method: 'DELETE' });
+  if (!response.ok) {
+    throw new Error('Failed to clear bookings');
+  }
+}

frontend/src/components/AvailabilityHeatmap.tsx

@@ -6,15 +6,16 @@ import {
   PopoverTrigger,
 } from '@/components/ui/popover';
 import { Button } from '@/components/ui/button';
-import { Check, X, Loader2 } from 'lucide-react';
+import { useState, useRef, useEffect } from 'react';
+import { Check, X, Loader2, ChevronLeft, ChevronRight, ChevronsRight } from 'lucide-react';
 
-const TIMEZONE = 'America/Toronto';
+const DEFAULT_TIMEZONE = 'America/Toronto';
 
 const dayNames = ['Mon', 'Tue', 'Wed', 'Thu', 'Fri'];
-const hours = [9, 10, 11, 12, 13, 14, 15, 16, 17];
+const hours = Array.from({ length: 24 }, (_, i) => i); // 0-23
 
-// Get the dates for Mon-Fri of the current week in a specific timezone
-const getWeekDates = (timezone: string): string[] => {
+// Get the dates for Mon-Fri of a week in a specific timezone, offset by N weeks
+const getWeekDates = (timezone: string, weekOffset: number = 0): string[] => {
   // Get "now" in the target timezone
   const now = new Date();
   const formatter = new Intl.DateTimeFormat('en-CA', {
@@ -33,7 +34,7 @@ const getWeekDates = (timezone: string): string[] => {
   const dayOfWeek = todayDate.getDay();
   const daysToMonday = dayOfWeek === 0 ? -6 : 1 - dayOfWeek;
 
-  const mondayDate = new Date(year, month - 1, day + daysToMonday);
+  const mondayDate = new Date(year, month - 1, day + daysToMonday + weekOffset * 7);
 
   return dayNames.map((_, i) => {
     const d = new Date(mondayDate);
@@ -73,12 +74,80 @@ const toUTCDate = (dateStr: string, hour: number, timezone: string): Date => {
   return utcDate;
 };
 
+const MIN_WEEK_OFFSET = 0;
+const DEFAULT_MAX_WEEK_OFFSET = 1;
+const EXPANDED_MAX_WEEK_OFFSET = 4;
+
+// Format timezone for display (e.g., "America/Toronto" -> "Toronto (EST)")
+const formatTimezoneDisplay = (timezone: string): string => {
+  try {
+    const parts = timezone.split('/');
+    const city = parts[parts.length - 1].replace(/_/g, ' ');
+    const now = new Date();
+    const formatter = new Intl.DateTimeFormat('en-US', {
+      timeZone: timezone,
+      timeZoneName: 'short',
+    });
+    const formattedParts = formatter.formatToParts(now);
+    const tzAbbrev = formattedParts.find((p) => p.type === 'timeZoneName')?.value || '';
+    return `${city} (${tzAbbrev})`;
+  } catch {
+    return timezone;
+  }
+};
+
+// Get timezone abbreviation (e.g., "America/Toronto" -> "EST")
+const getTimezoneAbbrev = (timezone: string): string => {
+  try {
+    const now = new Date();
+    const formatter = new Intl.DateTimeFormat('en-US', {
+      timeZone: timezone,
+      timeZoneName: 'short',
+    });
+    const parts = formatter.formatToParts(now);
+    return parts.find((p) => p.type === 'timeZoneName')?.value || '';
+  } catch {
+    return '';
+  }
+};
+
+// Convert an hour from one timezone to another
+const convertHourBetweenTimezones = (
+  hour: number,
+  dateStr: string,
+  fromTimezone: string,
+  toTimezone: string
+): number => {
+  try {
+    // Create a UTC date for the given hour in the source timezone
+    const utcDate = toUTCDate(dateStr, hour, fromTimezone);
+
+    // Format the hour in the target timezone
+    const targetHour = parseInt(
+      new Intl.DateTimeFormat('en-US', {
+        timeZone: toTimezone,
+        hour: 'numeric',
+        hour12: false,
+      }).format(utcDate)
+    );
+
+    return targetHour;
+  } catch {
+    return hour;
+  }
+};
+
 interface AvailabilityHeatmapProps {
   slots: TimeSlot[];
   selectedParticipants: Participant[];
   onSlotSelect: (slot: TimeSlot) => void;
   showPartialAvailability?: boolean;
   isLoading?: boolean;
+  weekOffset?: number;
+  onWeekOffsetChange?: (offset: number) => void;
+  displayTimezone?: string;
+  showSecondaryTimezone?: boolean;
+  secondaryTimezone?: string;
 }
 
 export const AvailabilityHeatmap = ({
@@ -87,13 +156,84 @@ export const AvailabilityHeatmap = ({
   onSlotSelect,
   showPartialAvailability = false,
   isLoading = false,
+  weekOffset = 0,
+  onWeekOffsetChange,
+  displayTimezone = DEFAULT_TIMEZONE,
+  showSecondaryTimezone = false,
+  secondaryTimezone = DEFAULT_TIMEZONE,
 }: AvailabilityHeatmapProps) => {
-  const weekDates = getWeekDates(TIMEZONE);
+  const [expanded, setExpanded] = useState(false);
+  const maxWeekOffset = expanded ? EXPANDED_MAX_WEEK_OFFSET : DEFAULT_MAX_WEEK_OFFSET;
+  const weekDates = getWeekDates(displayTimezone, weekOffset);
+
+  // Get current time info in display timezone
+  const getCurrentTimeInfo = () => {
+    const now = new Date();
+    const formatter = new Intl.DateTimeFormat('en-CA', {
+      timeZone: displayTimezone,
+      year: 'numeric',
+      month: '2-digit',
+      day: '2-digit',
+    });
+    const hourFormatter = new Intl.DateTimeFormat('en-US', {
+      timeZone: displayTimezone,
+      hour: 'numeric',
+      hour12: false,
+    });
+    const todayStr = formatter.format(now);
+    const currentHour = parseInt(hourFormatter.format(now));
+    return { todayStr, currentHour };
+  };
+
+  const { todayStr, currentHour } = getCurrentTimeInfo();
+  const todayIndex = weekDates.indexOf(todayStr);
+  const scrollContainerRef = useRef<HTMLDivElement>(null);
+  const currentHourRef = useRef<HTMLDivElement>(null);
+
+  // Track scroll position for fade indicators
+  const [canScrollUp, setCanScrollUp] = useState(false);
+  const [canScrollDown, setCanScrollDown] = useState(true);
+
+  const handleScroll = () => {
+    if (!scrollContainerRef.current) return;
+    const { scrollTop, scrollHeight, clientHeight } = scrollContainerRef.current;
+    setCanScrollUp(scrollTop > 10);
+    setCanScrollDown(scrollTop < scrollHeight - clientHeight - 10);
+  };
+
+  // Initialize scroll indicators after content loads
+  useEffect(() => {
+    const timer = setTimeout(handleScroll, 150);
+    return () => clearTimeout(timer);
+  }, [slots.length, selectedParticipants.length, isLoading]);
+
+  // Auto-scroll to position current hour as 3rd visible row
+  useEffect(() => {
+    // Only scroll when we have content to show
+    if (selectedParticipants.length === 0 || isLoading) return;
+
+    // Small delay to ensure DOM is ready after render
+    const timer = setTimeout(() => {
+      if (!scrollContainerRef.current) return;
+
+      const rowHeight = 52; // h-12 (48px) + gap (4px)
+      const rowsAbove = 2;
+
+      // Calculate which hour should be at the top
+      const targetHour = todayIndex >= 0
+        ? Math.max(0, currentHour - rowsAbove)
+        : 7; // Default to 7am for other weeks
+
+      scrollContainerRef.current.scrollTop = targetHour * rowHeight;
+    }, 100);
+
+    return () => clearTimeout(timer);
+  }, [weekOffset, todayIndex, currentHour, selectedParticipants.length, isLoading, slots.length]);
 
   // Find a slot that matches the given display timezone date/hour
   const getSlot = (dateStr: string, hour: number): TimeSlot | undefined => {
     // Convert display timezone date/hour to UTC
-    const targetUTC = toUTCDate(dateStr, hour, TIMEZONE);
+    const targetUTC = toUTCDate(dateStr, hour, displayTimezone);
 
     return slots.find((s) => {
       const slotDate = new Date(s.start_time);
@@ -115,7 +255,7 @@ export const AvailabilityHeatmap = ({
 
   const isSlotTooSoon = (dateStr: string, hour: number) => {
     // Convert to UTC and compare with current time
-    const slotTimeUTC = toUTCDate(dateStr, hour, TIMEZONE);
+    const slotTimeUTC = toUTCDate(dateStr, hour, displayTimezone);
     const now = new Date();
     const twoHoursFromNow = new Date(now.getTime() + 2 * 60 * 60 * 1000);
     return slotTimeUTC < twoHoursFromNow;
@@ -167,19 +307,115 @@ export const AvailabilityHeatmap = ({
     <div className="bg-card rounded-xl shadow-card p-6 animate-slide-up">
       <div className="mb-6 flex justify-between items-start">
         <div>
-          <h3 className="text-lg font-semibold text-foreground">
-            Common Availability — Week of {getWeekDateRange()}
-          </h3>
+          <div className="flex items-center gap-2">
+            <h3 className="text-lg font-semibold text-foreground">
+              Common Availability — Week of {getWeekDateRange()}
+            </h3>
+          </div>
           <p className="text-sm text-muted-foreground mt-1">
             {selectedParticipants.length} participant{selectedParticipants.length > 1 ? 's' : ''}: {selectedParticipants.map(p => p.name.split(' ')[0]).join(', ')}
+            <span className="mx-2">•</span>
+            <span className="text-primary font-medium">
+              {`Times in ${formatTimezoneDisplay(displayTimezone)}`}
+            </span>
           </p>
         </div>
+        {onWeekOffsetChange && (
+          <div className="flex items-center gap-1">
+            <Button
+              variant="ghost"
+              size="icon"
+              className="h-8 w-8"
+              disabled={weekOffset <= MIN_WEEK_OFFSET}
+              onClick={() => onWeekOffsetChange(weekOffset - 1)}
+            >
+              <ChevronLeft className="w-4 h-4" />
+            </Button>
+            {weekOffset !== 0 && (
+              <Button
+                variant="ghost"
+                size="sm"
+                className="h-8 text-xs"
+                onClick={() => onWeekOffsetChange(0)}
+              >
+                This week
+              </Button>
+            )}
+            {weekOffset < maxWeekOffset ? (
+              <Button
+                variant="ghost"
+                size="icon"
+                className="h-8 w-8"
+                onClick={() => onWeekOffsetChange(weekOffset + 1)}
+              >
+                <ChevronRight className="w-4 h-4" />
+              </Button>
+            ) : !expanded ? (
+              <Button
+                variant="outline"
+                size="sm"
+                className="h-8 text-xs gap-1"
+                onClick={() => setExpanded(true)}
+              >
+                <ChevronsRight className="w-3.5 h-3.5" />
+                Look further ahead
+              </Button>
+            ) : (
+              <Button
+                variant="ghost"
+                size="icon"
+                className="h-8 w-8"
+                disabled
+              >
+                <ChevronRight className="w-4 h-4" />
+              </Button>
+            )}
+          </div>
+        )}
       </div>
 
-      <div className="overflow-x-auto">
-        <div className="min-w-[600px]">
-          <div className="grid grid-cols-[60px_repeat(5,1fr)] gap-1 mb-2">
-            <div></div>
+      <div className="relative">
+        {/* Scroll fade indicator - top */}
+        <div
+          className={cn(
+            "absolute top-0 left-0 right-0 h-8 bg-gradient-to-b from-card to-transparent z-20 pointer-events-none transition-opacity duration-200",
+            canScrollUp ? "opacity-100" : "opacity-0"
+          )}
+        />
+        {/* Scroll fade indicator - bottom */}
+        <div
+          className={cn(
+            "absolute bottom-0 left-0 right-0 h-12 bg-gradient-to-t from-card via-card/80 to-transparent z-20 pointer-events-none transition-opacity duration-200 flex items-end justify-center pb-2",
+            canScrollDown ? "opacity-100" : "opacity-0"
+          )}
+        >
+          <span className="text-xs text-muted-foreground animate-pulse">↓ Scroll for more hours</span>
+        </div>
+
+        <div
+          className="overflow-x-auto overflow-y-auto max-h-[500px]"
+          ref={scrollContainerRef}
+          onScroll={handleScroll}
+        >
+          <div className="min-w-[600px]">
+          <div className={cn(
+            "grid gap-1 mb-2 sticky top-0 bg-card z-10",
+            showSecondaryTimezone
+              ? "grid-cols-[50px_50px_repeat(5,1fr)]"
+              : "grid-cols-[60px_repeat(5,1fr)]"
+          )}>
+            {showSecondaryTimezone ? (
+              <>
+                <div className="text-center text-xs font-medium text-primary py-2">
+                  {getTimezoneAbbrev(displayTimezone)}
+                </div>
+                <div className="text-center text-xs font-medium text-muted-foreground py-2">
+                  {getTimezoneAbbrev(secondaryTimezone)}
+                </div>
+              </>
+            ) : (
+              <div></div>
+            )}
             {dayNames.map((dayName, i) => (
               <div
                 key={dayName}
@@ -195,10 +431,36 @@ export const AvailabilityHeatmap = ({
 
           <div className="space-y-1">
             {hours.map((hour) => (
-              <div key={hour} className="grid grid-cols-[60px_repeat(5,1fr)] gap-1">
-                <div className="text-xs text-muted-foreground flex items-center justify-end pr-3">
-                  {formatHour(hour)}
-                </div>
+              <div
+                key={hour}
+                ref={todayIndex >= 0 && hour === currentHour ? currentHourRef : undefined}
+                className={cn(
+                  "grid gap-1",
+                  showSecondaryTimezone
+                    ? "grid-cols-[50px_50px_repeat(5,1fr)]"
+                    : "grid-cols-[60px_repeat(5,1fr)]"
+                )}
+              >
+                {showSecondaryTimezone ? (
+                  <>
+                    <div className="text-xs text-primary font-medium flex items-center justify-center gap-1">
+                      {todayIndex >= 0 && hour === currentHour && (
+                        <span className="w-2 h-2 rounded-full bg-primary animate-pulse" />
+                      )}
+                      {formatHour(hour)}
+                    </div>
+                    <div className="text-xs text-muted-foreground flex items-center justify-center">
+                      {formatHour(convertHourBetweenTimezones(hour, weekDates[0] || '', displayTimezone, secondaryTimezone))}
+                    </div>
+                  </>
+                ) : (
+                  <div className="text-xs text-muted-foreground flex items-center justify-end pr-3 gap-1">
+                    {todayIndex >= 0 && hour === currentHour && (
+                      <span className="w-2 h-2 rounded-full bg-primary animate-pulse" />
+                    )}
+                    {formatHour(hour)}
+                  </div>
+                )}
                 {weekDates.map((dateStr, dayIndex) => {
                   const slot = getSlot(dateStr, hour);
                   const dayName = dayNames[dayIndex];
@@ -273,6 +535,7 @@ export const AvailabilityHeatmap = ({
           </div>
         </div>
       </div>
+      </div>
 
       <div className="flex items-center justify-center gap-6 mt-6 pt-4 border-t border-border">
         <div className="flex items-center gap-2">

frontend/src/components/AvailabilityHeatmapV2.tsx

@@ -0,0 +1,474 @@
+import { TimeSlot, Participant } from '@/types/calendar';
+import { cn } from '@/lib/utils';
+import {
+  Popover,
+  PopoverContent,
+  PopoverTrigger,
+} from '@/components/ui/popover';
+import { Button } from '@/components/ui/button';
+import { useState, useMemo, useRef, useEffect } from 'react';
+import { Check, X, Loader2, ChevronLeft, ChevronRight, ChevronsRight, Clock, Calendar as CalendarIcon, Sun, Moon, Users } from 'lucide-react';
+import { Tooltip, TooltipContent, TooltipProvider, TooltipTrigger } from '@/components/ui/tooltip';
+
+const DEFAULT_TIMEZONE = 'America/Toronto';
+const dayNames = ['Mon', 'Tue', 'Wed', 'Thu', 'Fri'];
+const WORKING_HOUR_START = 8; // 8 AM
+const WORKING_HOUR_END = 18; // 6 PM
+const ALL_HOURS = Array.from({ length: 24 }, (_, i) => i);
+const WORKING_HOURS = Array.from({ length: WORKING_HOUR_END - WORKING_HOUR_START + 1 }, (_, i) => i + WORKING_HOUR_START);
+
+// Helper to check if a slot is in the past or too close (2h buffer)
+const isSlotTooSoon = (slotDate: number) => {
+  const now = Date.now();
+  const twoHoursFromNow = now + 2 * 60 * 60 * 1000;
+  return slotDate < twoHoursFromNow;
+};
+
+// Reuse previous timezone helpers or simplify
+const getWeekDates = (timezone: string, weekOffset: number = 0): Date[] => {
+  const now = new Date();
+  const formatter = new Intl.DateTimeFormat('en-CA', {
+    timeZone: timezone,
+    year: 'numeric',
+    month: '2-digit',
+    day: '2-digit',
+  });
+
+  const todayStr = formatter.format(now);
+  const [year, month, day] = todayStr.split('-').map(Number);
+
+  const todayDate = new Date(year, month - 1, day);
+  const dayOfWeek = todayDate.getDay();
+  // If Sunday (0), go back 6 days to Monday. If Mon (1), go back 0. If Sat (6), go back 5.
+  // Actually standard logic: Mon=1...Sun=7. 
+  // Let's assume standard ISO week start (Mon)
+  const daysToMonday = dayOfWeek === 0 ? -6 : 1 - dayOfWeek;
+  const mondayDate = new Date(year, month - 1, day + daysToMonday + weekOffset * 7);
+
+  return Array.from({ length: 5 }, (_, i) => {
+    const d = new Date(mondayDate);
+    d.setDate(mondayDate.getDate() + i);
+    return d;
+  });
+};
+
+const formatTimezoneDisplay = (timezone: string): string => {
+  try {
+    const parts = timezone.split('/');
+    const city = parts[parts.length - 1].replace(/_/g, ' ');
+    return city;
+  } catch {
+    return timezone;
+  }
+};
+
+interface AvailabilityHeatmapV2Props {
+  slots: TimeSlot[];
+  selectedParticipants: Participant[];
+  onSlotSelect: (slot: TimeSlot) => void;
+  showPartialAvailability?: boolean;
+  isLoading?: boolean;
+  weekOffset?: number;
+  onWeekOffsetChange?: (offset: number) => void;
+  displayTimezone?: string;
+  showSecondaryTimezone?: boolean;
+  secondaryTimezone?: string;
+}
+
+export const AvailabilityHeatmapV2 = ({
+  slots,
+  selectedParticipants,
+  onSlotSelect,
+  showPartialAvailability = false,
+  isLoading = false,
+  weekOffset = 0,
+  onWeekOffsetChange,
+  displayTimezone = DEFAULT_TIMEZONE,
+  showSecondaryTimezone = false,
+  secondaryTimezone = DEFAULT_TIMEZONE,
+}: AvailabilityHeatmapV2Props) => {
+  const [showFullDay, setShowFullDay] = useState(false);
+  const activeHours = showFullDay ? ALL_HOURS : WORKING_HOURS;
+
+  const weekDates = useMemo(() => getWeekDates(displayTimezone, weekOffset), [displayTimezone, weekOffset]);
+
+  // Pre-compute slots lookup map for O(1) access
+  // Key: YYYY-MM-DD:Hour
+  const slotsMap = useMemo(() => {
+    const map = new Map<string, TimeSlot>();
+    slots.forEach(slot => {
+      // Assuming slot.start_time is ISO string. 
+      // We need to match it to our grid's local time logic.
+      // This part is "flaky" in the original. 
+      // The slot comes with a specific absolute time.
+      // We want to place it in the intersection of "Day (in DisplayTZ)" and "Hour (in DisplayTZ)".
+
+      const d = new Date(slot.start_time);
+      // Format to DisplayTZ to find coordinate
+      const formatter = new Intl.DateTimeFormat('en-CA', {
+        timeZone: displayTimezone,
+        year: 'numeric',
+        month: '2-digit',
+        day: '2-digit',
+        hour: 'numeric',
+        hour12: false
+      });
+      // "2023-10-25, 14"
+      const parts = formatter.formatToParts(d);
+      const year = parts.find(p => p.type === 'year')?.value;
+      const month = parts.find(p => p.type === 'month')?.value;
+      const day = parts.find(p => p.type === 'day')?.value;
+      const hour = parts.find(p => p.type === 'hour')?.value;
+
+      if (year && month && day && hour) {
+        // Hour in 24h format might be "24" in some locales? No `hour12: false` gives 0-23 usually.
+        // But Intl sometimes returns "24"? No, 0-23.
+        let h = parseInt(hour, 10);
+        if (h === 24) h = 0; // Just in case
+
+        const key = `${year}-${month}-${day}:${h}`;
+        map.set(key, slot);
+      }
+    });
+    return map;
+  }, [slots, displayTimezone]);
+
+  const formatDateKey = (date: Date) => {
+    const y = date.getFullYear();
+    const m = String(date.getMonth() + 1).padStart(2, '0');
+    const d = String(date.getDate()).padStart(2, '0');
+    return `${y}-${m}-${d}`;
+  };
+
+  const formatDisplayDate = (date: Date) => {
+    return date.toLocaleDateString('en-US', { weekday: 'short', month: 'short', day: 'numeric' });
+  };
+
+  const getSlotForCell = (date: Date, hour: number) => {
+    const key = `${formatDateKey(date)}:${hour}`;
+    return slotsMap.get(key);
+  };
+
+  const formatHour = (hour: number) => {
+    return new Date(0, 0, 0, hour).toLocaleTimeString('en-US', {
+      hour: 'numeric',
+      hour12: true,
+    });
+  };
+
+  // Move hooks to top level to avoid conditional hook execution error
+  const tzOffsetDiff = useMemo(() => {
+    try {
+      const now = new Date();
+      const p = parseInt(new Intl.DateTimeFormat('en-US', { timeZone: displayTimezone, hour: 'numeric', hour12: false }).format(now));
+      const s = parseInt(new Intl.DateTimeFormat('en-US', { timeZone: secondaryTimezone, hour: 'numeric', hour12: false }).format(now));
+      let diff = s - p;
+      if (diff > 12) diff -= 24;
+      if (diff < -12) diff += 24;
+      return diff;
+    } catch {
+      return 0;
+    }
+  }, [displayTimezone, secondaryTimezone]);
+
+  const timeColWidth = showSecondaryTimezone ? "120px" : "80px";
+
+  if (selectedParticipants.length === 0) {
+    return (
+      <div className="flex flex-col items-center justify-center p-12 border-2 border-dashed border-border/50 rounded-xl bg-muted/20 animate-fade-in">
+        <UsersPlaceholder />
+        <h3 className="text-xl font-semibold mt-4">No participants selected</h3>
+        <p className="text-muted-foreground text-center max-w-sm mt-2">
+          Select team members from the list above to compare calendars and find the perfect meeting time.
+        </p>
+      </div>
+    );
+  }
+
+  return (
+    <div className="space-y-4 animate-in fade-in slide-in-from-bottom-4 duration-500">
+      {/* Controls Bar */}
+      <div className="flex flex-col sm:flex-row sm:items-center justify-between gap-4 bg-card p-4 rounded-xl border border-border shadow-sm">
+        <div className="flex items-center gap-4">
+          <div className="flex items-center gap-2">
+            <Button
+              variant="outline"
+              size="icon"
+              className="h-9 w-9"
+              onClick={() => onWeekOffsetChange?.(weekOffset - 1)}
+              disabled={!onWeekOffsetChange || weekOffset <= 0}
+            >
+              <ChevronLeft className="h-4 w-4" />
+            </Button>
+            <div className="flex flex-col items-center min-w-[140px]">
+              <span className="text-sm font-semibold">
+                {weekDates[0]?.toLocaleDateString('en-US', { month: 'short', day: 'numeric' })}
+                {' - '}
+                {weekDates[4]?.toLocaleDateString('en-US', { month: 'short', day: 'numeric' })}
+              </span>
+              <span className="text-xs text-muted-foreground">
+                {weekOffset === 0 ? "This Week" : weekOffset === 1 ? "Next Week" : `${weekOffset} weeks out`}
+              </span>
+            </div>
+            <Button
+              variant="outline"
+              size="icon"
+              className="h-9 w-9"
+              onClick={() => onWeekOffsetChange?.(weekOffset + 1)}
+              disabled={!onWeekOffsetChange}
+            >
+              <ChevronRight className="h-4 w-4" />
+            </Button>
+          </div>
+
+          <div className="h-8 w-px bg-border hidden sm:block" />
+
+          <div className="flex items-center gap-2 text-sm text-muted-foreground bg-muted/50 px-3 py-1.5 rounded-md">
+            <Clock className="w-4 h-4" />
+            {formatTimezoneDisplay(displayTimezone)}
+          </div>
+        </div>
+
+        <div className="flex items-center gap-2">
+          <Button
+            variant={showFullDay ? "outline" : "secondary"}
+            size="sm"
+            onClick={() => setShowFullDay(!showFullDay)}
+            className="text-xs"
+          >
+            {showFullDay ? (
+              <>
+                <Sun className="w-3.5 h-3.5 mr-2" />
+                Show Work Hours
+              </>
+            ) : (
+              <>
+                <Moon className="w-3.5 h-3.5 mr-2" />
+                Show Full Day
+              </>
+            )}
+          </Button>
+        </div>
+      </div>
+
+      {/* Main Grid Card */}
+      <div className="bg-card w-full overflow-hidden rounded-xl border border-border shadow-md">
+        {isLoading && (
+          <div className="absolute inset-0 bg-background/50 backdrop-blur-[1px] z-50 flex items-center justify-center">
+            <Loader2 className="w-10 h-10 animate-spin text-primary" />
+          </div>
+        )}
+
+        <div className="overflow-auto max-h-[600px] w-full relative">
+          <div className="min-w-[700px]">
+            {/* Grid Header */}
+            <div
+              className="grid sticky top-0 z-30 bg-card border-b border-border shadow-sm"
+              style={{ gridTemplateColumns: `${timeColWidth} repeat(5, 1fr)` }}
+            >
+              <div className="sticky left-0 z-40 bg-card text-xs font-semibold text-muted-foreground self-center p-3 text-right border-r border-border/50 flex flex-col items-end gap-1">
+                <span>{formatTimezoneDisplay(displayTimezone)}</span>
+                {showSecondaryTimezone && (
+                  <span className="text-[10px] text-muted-foreground/60 font-normal">{formatTimezoneDisplay(secondaryTimezone)}</span>
+                )}
+              </div>
+              {weekDates.map(date => {
+                const isToday = new Date().toDateString() === date.toDateString();
+                return (
+                  <div key={date.toISOString()} className={cn(
+                    "text-center p-3 transition-colors border-r border-border/30 last:border-0",
+                    isToday ? "bg-primary/5 text-primary font-bold" : "text-foreground"
+                  )}>
+                    <div className="text-sm">{date.toLocaleDateString('en-US', { weekday: 'short' })}</div>
+                    <div className={cn("text-2xl", isToday ? "font-bold" : "font-light")}>
+                      {date.getDate()}
+                    </div>
+                  </div>
+                );
+              })}
+            </div>
+
+            {/* Grid Body */}
+            <div className="relative">
+              {activeHours.map((hour) => {
+                const isNight = hour < 8 || hour >= 18;
+
+                // Calculate secondary time
+                let secondaryHour = hour + tzOffsetDiff;
+                if (secondaryHour >= 24) secondaryHour -= 24;
+                if (secondaryHour < 0) secondaryHour += 24;
+
+                return (
+                  <div
+                    key={hour}
+                    className={cn(
+                      "grid group items-stretch transition-colors border-b border-border/30 last:border-0",
+                      isNight ? "bg-muted/30" : "bg-card",
+                      "hover:bg-muted/10"
+                    )}
+                    style={{ gridTemplateColumns: `${timeColWidth} repeat(5, 1fr)` }}
+                  >
+                    {/* Time Label - Sticky Left */}
+                    <div className={cn(
+                      "text-xs text-muted-foreground font-medium text-right pr-4 py-3 flex flex-col items-end justify-center gap-0.5",
+                      "sticky left-0 z-20 border-r border-border/50",
+                      isNight ? "bg-muted/30 backdrop-blur-md" : "bg-card"
+                    )}>
+                      <div className="flex items-center gap-1.5">
+                        {isNight ? (
+                          <Moon className="w-3 h-3 text-slate-400/50" />
+                        ) : (
+                          <Sun className="w-3 h-3 text-amber-500/50" />
+                        )}
+                        <span>{formatHour(hour)}</span>
+                      </div>
+                      {showSecondaryTimezone && (
+                        <span className="text-[10px] text-muted-foreground/60 font-mono">
+                          {formatHour(secondaryHour)}
+                        </span>
+                      )}
+                    </div>
+
+                    {/* Days */}
+                    {weekDates.map(date => {
+                      const slot = getSlotForCell(date, hour);
+                      const tooSoon = slot ? isSlotTooSoon(new Date(slot.start_time).getTime()) : true;
+
+                      // Availability logic
+                      const availability = slot?.availability || 'none';
+                      const isNone = availability === 'none';
+                      const isPartial = availability === 'partial' && showPartialAvailability;
+                      const isFull = availability === 'full';
+                      const isPartialHidden = availability === 'partial' && !showPartialAvailability;
+
+                      // Styling
+                      let bgClass = ""; // Default transparent
+
+                      if (!slot) {
+                        bgClass = "bg-muted/10 pattern-diagonal-lines opacity-50";
+                      } else if (tooSoon) {
+                        bgClass = "bg-muted/20 pattern-diagonal-lines cursor-not-allowed border border-border/10";
+                      } else if (isFull) {
+                        bgClass = "bg-emerald-500/90 hover:bg-emerald-600 shadow-sm";
+                      } else if (isPartial) {
+                        bgClass = "bg-amber-400/80 hover:bg-amber-500 shadow-sm";
+                      } else if (isNone || isPartialHidden) {
+                        bgClass = "bg-muted/50 hover:bg-muted/70 border border-border/20";
+                      }
+
+                      return (
+                        <div key={date.toISOString()} className="p-1 h-[52px] border-r border-border/30 last:border-0">
+                          {slot ? (
+                            <Popover>
+                              <PopoverTrigger asChild disabled={tooSoon}>
+                                <div className={cn(
+                                  "w-full h-full rounded-md transition-all duration-200 cursor-pointer flex items-center justify-center group/cell relative overflow-hidden",
+                                  bgClass,
+                                  !tooSoon && (isFull || isPartial) ? "scale-[0.98] hover:scale-100 hover:ring-2 ring-primary/20" : ""
+                                )}>
+                                  {/* Mini Indicators for color-blind accessibility or density */}
+                                  {isFull && <Check className="w-4 h-4 text-white opacity-0 group-hover/cell:opacity-100 transition-opacity" />}
+                                </div>
+                              </PopoverTrigger>
+                              <PopoverContent className="w-72 p-0 rounded-xl overflow-hidden shadow-xl border-border" side="right" align={hour >= 12 ? "end" : "start"}>
+                                <div className="p-4 bg-muted/30 border-b border-border/50">
+                                  <h4 className="font-semibold text-base flex items-center gap-2">
+                                    <CalendarIcon className="w-4 h-4 text-muted-foreground" />
+                                    {formatDisplayDate(date)}
+                                  </h4>
+                                  <div className="text-sm text-muted-foreground mt-1 flex items-center gap-2">
+                                    <Clock className="w-4 h-4" />
+                                    {formatHour(hour)} - {formatHour(hour + 1)}
+                                  </div>
+                                </div>
+
+                                <div className="p-4 space-y-3 max-h-[300px] overflow-y-auto">
+                                  <div className="space-y-2">
+                                    {selectedParticipants.map(participant => {
+                                      const isAvailable = slot.availableParticipants.includes(participant.name);
+                                      return (
+                                        <div key={participant.id} className="flex items-center justify-between text-sm p-2 rounded-lg hover:bg-muted/50 transition-colors">
+                                          <div className="flex items-center gap-3">
+                                            <div className={cn(
+                                              "w-2 h-2 rounded-full",
+                                              isAvailable ? "bg-emerald-500" : "bg-destructive"
+                                            )} />
+                                            <span className={cn(!isAvailable && "text-muted-foreground")}>
+                                              {participant.name}
+                                            </span>
+                                          </div>
+                                          {isAvailable ? (
+                                            <Check className="w-4 h-4 text-emerald-500" />
+                                          ) : (
+                                            <span className="text-xs text-muted-foreground">Busy</span>
+                                          )}
+                                        </div>
+                                      );
+                                    })}
+                                  </div>
+
+                                  {(!isNone && !tooSoon) && (
+                                    <Button
+                                      className="w-full mt-4 bg-emerald-600 hover:bg-emerald-700 text-white"
+                                      onClick={() => onSlotSelect(slot)}
+                                    >
+                                      Schedule Meeting
+                                    </Button>
+                                  )}
+                                </div>
+                              </PopoverContent>
+                            </Popover>
+                          ) : (
+                            // Placeholder for missing slots
+                            <div className="w-full h-full rounded-md bg-muted/5 border border-dashed border-border/30"></div>
+                          )}
+                        </div>
+                      );
+                    })}
+                  </div>
+                );
+              })}
+            </div>
+          </div>
+        </div>
+
+        {/* Legend */}
+        <div className="flex flex-wrap items-center justify-center bg-muted/20 border-t p-3 gap-6 text-sm">
+          <div className="flex items-center gap-2">
+            <div className="w-3 h-3 rounded-full bg-emerald-500 shadow-sm"></div>
+            <span className="font-medium text-foreground">All Available</span>
+          </div>
+          {showPartialAvailability && (
+            <div className="flex items-center gap-2">
+              <div className="w-3 h-3 rounded-full bg-amber-400 shadow-sm"></div>
+              <span className="font-medium text-foreground">Partial Match</span>
+            </div>
+          )}
+          <div className="flex items-center gap-2">
+            <div className="w-3 h-3 rounded bg-muted/50 border border-border/20"></div>
+            <span className="text-muted-foreground">Busy / No Match</span>
+          </div>
+          <div className="flex items-center gap-2">
+            <div className="w-3 h-3 rounded bg-muted/20 pattern-diagonal-lines border border-border/10"></div>
+            <span className="text-muted-foreground">Past / Too Soon</span>
+          </div>
+        </div>
+      </div>
+    </div>
+  );
+};
+
+function UsersPlaceholder() {
+  return (
+    <div className="relative w-16 h-16 mb-2">
+      <div className="absolute top-0 left-0 w-10 h-10 rounded-full bg-muted border-2 border-background flex items-center justify-center">
+        <Users className="w-5 h-5 text-muted-foreground" />
+      </div>
+      <div className="absolute bottom-0 right-0 w-10 h-10 rounded-full bg-muted border-2 border-background flex items-center justify-center">
+        <Users className="w-5 h-5 text-muted-foreground" />
+      </div>
+    </div>
+  );
+}
+
+// Importing Users icon since it was missing in imports

frontend/src/components/Header.tsx

@@ -1,7 +1,27 @@
-import { Calendar } from 'lucide-react';
+import { Calendar, Moon, Sun } from 'lucide-react';
 import { getAvatarColor } from '@/lib/utils';
+import { useState, useEffect } from 'react';
+import { Button } from './ui/button';
 
 export const Header = () => {
+  const [theme, setTheme] = useState<'light' | 'dark'>(() => {
+    if (typeof window !== 'undefined') {
+      return localStorage.getItem('theme') === 'dark' ? 'dark' : 'light';
+    }
+    return 'light';
+  });
+
+  useEffect(() => {
+    const root = window.document.documentElement;
+    root.classList.remove('light', 'dark');
+    root.classList.add(theme);
+    localStorage.setItem('theme', theme);
+  }, [theme]);
+
+  const toggleTheme = () => {
+    setTheme(prev => prev === 'light' ? 'dark' : 'light');
+  };
+
   return (
     <header className="border-b border-border bg-card/50 backdrop-blur-sm sticky top-0 z-50">
       <div className="container max-w-5xl mx-auto px-4 py-4 flex items-center justify-between">
@@ -14,7 +34,15 @@ export const Header = () => {
             <p className="text-xs text-muted-foreground">Calendar Coordination</p>
           </div>
         </div>
-        <div className="flex items-center gap-2">
+        <div className="flex items-center gap-4">
+          <Button variant="ghost" size="icon" onClick={toggleTheme} className="rounded-full">
+            {theme === 'light' ? (
+              <Sun className="h-5 w-5 text-amber-500" />
+            ) : (
+              <Moon className="h-5 w-5 text-slate-400" />
+            )}
+            <span className="sr-only">Toggle theme</span>
+          </Button>
           <div
             className="w-8 h-8 rounded-full flex items-center justify-center text-sm font-medium text-white"
             style={{ backgroundColor: getAvatarColor("AR") }}

frontend/src/components/ParticipantManager.tsx

@@ -3,9 +3,15 @@ import { Participant } from '@/types/calendar';
 import { Input } from '@/components/ui/input';
 import { Button } from '@/components/ui/button';
 import { Label } from '@/components/ui/label';
-import { UserPlus, Trash2, User, Pencil, Check, X, AlertCircle } from 'lucide-react';
+import { UserPlus, Trash2, User, Pencil, Check, X, AlertCircle, Info } from 'lucide-react';
 import { useToast } from '@/hooks/use-toast';
-import { getAvatarColor } from '@/lib/utils';
+import { getAvatarColor, getCalendarNameFromUrl } from '@/lib/utils';
+import {
+  Tooltip,
+  TooltipContent,
+  TooltipProvider,
+  TooltipTrigger,
+} from '@/components/ui/tooltip';
 
 interface ParticipantManagerProps {
   participants: Participant[];
@@ -236,9 +242,19 @@ export const ParticipantManager = ({
                           <span>{participant.email}</span>
                           <span className="text-muted-foreground/60">•</span>
                           {participant.icsLink ? (
-                            <span className="text-primary truncate max-w-[200px]" title={participant.icsLink}>
-                              ICS linked
-                            </span>
+                            <TooltipProvider>
+                              <Tooltip>
+                                <TooltipTrigger asChild>
+                                  <span className="text-primary truncate max-w-[200px] cursor-help flex items-center gap-1" title={participant.icsLink}>
+                                    📅 {getCalendarNameFromUrl(participant.icsLink) || 'Calendar linked'}
+                                    <Info className="w-3 h-3 opacity-50" />
+                                  </span>
+                                </TooltipTrigger>
+                                <TooltipContent side="top" className="max-w-[220px]">
+                                  <p>Availability is based on this calendar only. Other calendars on the same account are not included.</p>
+                                </TooltipContent>
+                              </Tooltip>
+                            </TooltipProvider>
                           ) : (
                             <span className="text-amber-600 flex items-center gap-1">
                               <AlertCircle className="w-3 h-3" />

frontend/src/components/ParticipantSelector.tsx

@@ -1,8 +1,14 @@
-import { useState } from 'react';
+import { useState, useRef, useCallback, useEffect } from 'react';
 import { Participant } from '@/types/calendar';
 import { Input } from '@/components/ui/input';
-import { X, Plus, Search, AlertCircle } from 'lucide-react';
-import { cn, getAvatarColor } from '@/lib/utils';
+import { X, Plus, Search, AlertCircle, Info } from 'lucide-react';
+import { cn, getAvatarColor, getCalendarNameFromUrl } from '@/lib/utils';
+import {
+  Tooltip,
+  TooltipContent,
+  TooltipProvider,
+  TooltipTrigger,
+} from '@/components/ui/tooltip';
 
 interface ParticipantSelectorProps {
   participants: Participant[];
@@ -17,6 +23,19 @@ export const ParticipantSelector = ({
 }: ParticipantSelectorProps) => {
   const [searchQuery, setSearchQuery] = useState('');
   const [isDropdownOpen, setIsDropdownOpen] = useState(false);
+  const [highlightedIndex, setHighlightedIndex] = useState(0);
+  const inputRef = useRef<HTMLInputElement>(null);
+  const containerRef = useRef<HTMLDivElement>(null);
+
+  useEffect(() => {
+    const handleClickOutside = (e: MouseEvent) => {
+      if (containerRef.current && !containerRef.current.contains(e.target as Node)) {
+        setIsDropdownOpen(false);
+      }
+    };
+    document.addEventListener('mousedown', handleClickOutside);
+    return () => document.removeEventListener('mousedown', handleClickOutside);
+  }, []);
 
   const filteredParticipants = participants.filter(
     (p) =>
@@ -25,14 +44,43 @@ export const ParticipantSelector = ({
         p.email.toLowerCase().includes(searchQuery.toLowerCase()))
   );
 
-  const addParticipant = (participant: Participant) => {
+  const addParticipant = useCallback((participant: Participant) => {
     onSelectionChange([...selectedParticipants, participant]);
     setSearchQuery('');
-    setIsDropdownOpen(false);
+    // Keep dropdown open for multi-select; clamp highlight to new list length
+    setHighlightedIndex((prev) => {
+      const newLength = filteredParticipants.length - 1;
+      return prev >= newLength ? Math.max(0, newLength - 1) : prev;
+    });
+    // Keep focus on input so user can continue selecting
+    requestAnimationFrame(() => inputRef.current?.focus());
+  }, [onSelectionChange, selectedParticipants, filteredParticipants.length]);
+
+  const handleKeyDown = (e: React.KeyboardEvent) => {
+    if (!isDropdownOpen || filteredParticipants.length === 0) return;
+
+    if (e.key === 'ArrowDown') {
+      e.preventDefault();
+      setHighlightedIndex((prev) =>
+        prev < filteredParticipants.length - 1 ? prev + 1 : 0
+      );
+    } else if (e.key === 'ArrowUp') {
+      e.preventDefault();
+      setHighlightedIndex((prev) =>
+        prev > 0 ? prev - 1 : filteredParticipants.length - 1
+      );
+    } else if (e.key === 'Enter') {
+      e.preventDefault();
+      addParticipant(filteredParticipants[highlightedIndex]);
+    } else if (e.key === 'Escape') {
+      setIsDropdownOpen(false);
+    }
   };
 
   const removeParticipant = (participantId: string) => {
     onSelectionChange(selectedParticipants.filter((p) => p.id !== participantId));
+    setIsDropdownOpen(false);
+    inputRef.current?.blur();
   };
 
   const getInitials = (name: string) => {
@@ -45,27 +93,83 @@ export const ParticipantSelector = ({
   };
 
   return (
-    <div className="space-y-4">
-      <div className="relative">
-        <Search className="absolute left-3 top-1/2 -translate-y-1/2 w-4 h-4 text-muted-foreground" />
+    <div ref={containerRef} className="space-y-4">
+      <div
+        className={cn(
+          "relative min-h-[48px] bg-background border border-border rounded-lg shadow-sm flex flex-wrap items-center gap-2 px-3 py-1.5 transition-all",
+          "focus-within:ring-2 focus-within:ring-primary/20 focus-within:border-primary"
+        )}
+        onClick={() => inputRef.current?.focus()}
+      >
+        <Search className="w-4 h-4 text-muted-foreground shrink-0 mr-1" />
+
+        {selectedParticipants.map((participant) => (
+          <div
+            key={participant.id}
+            className={cn(
+              "flex items-center gap-1.5 bg-accent text-accent-foreground pl-2 pr-1 py-1 rounded-full text-xs font-medium animate-scale-in",
+              "border border-primary/10 group hover:border-destructive/30 hover:bg-destructive/10 hover:text-destructive transition-colors cursor-default"
+            )}
+            onClick={(e) => e.stopPropagation()}
+          >
+            <div
+              className="w-4 h-4 rounded-full flex items-center justify-center text-[9px] font-bold text-white shrink-0"
+              style={{ backgroundColor: getAvatarColor(participant.name) }}
+            >
+              {getInitials(participant.name)}
+            </div>
+            <span className="max-w-[100px] truncate">{participant.name.split(' ')[0]}</span>
+            {!participant.icsLink && (
+              <AlertCircle className="w-3 h-3 text-amber-600 shrink-0" title="No calendar linked" />
+            )}
+            <button
+              onClick={() => removeParticipant(participant.id)}
+              className="w-4 h-4 rounded-full hover:bg-black/10 dark:hover:bg-white/10 flex items-center justify-center transition-colors shrink-0"
+            >
+              <X className="w-2.5 h-2.5" />
+            </button>
+          </div>
+        ))}
+
         <Input
-          placeholder="Search people..."
+          ref={inputRef}
+          placeholder={selectedParticipants.length === 0 ? "Search people..." : "Add more..."}
           value={searchQuery}
           onChange={(e) => {
             setSearchQuery(e.target.value);
+            setHighlightedIndex(0);
             setIsDropdownOpen(true);
           }}
           onFocus={() => setIsDropdownOpen(true)}
-          className="pl-10 h-12 bg-background border-border"
+          onKeyDown={handleKeyDown}
+          className="flex-1 min-w-[100px] h-7 border-none shadow-none focus-visible:ring-0 p-0 text-sm bg-transparent placeholder:text-muted-foreground/70"
         />
 
+        {isDropdownOpen && (
+          <button
+            onClick={(e) => {
+              e.stopPropagation();
+              setIsDropdownOpen(false);
+              inputRef.current?.blur();
+            }}
+            className="p-1 hover:bg-muted rounded-full transition-colors ml-1"
+            title="Close"
+          >
+            <X className="w-4 h-4 text-muted-foreground" />
+          </button>
+        )}
+
         {isDropdownOpen && filteredParticipants.length > 0 && (
-          <div className="absolute z-10 w-full mt-2 bg-popover border border-border rounded-lg shadow-popover animate-scale-in overflow-hidden">
-            {filteredParticipants.map((participant) => (
+          <div className="absolute top-full left-0 z-50 w-full mt-2 bg-popover border border-border rounded-lg shadow-popover animate-scale-in overflow-hidden">
+            {filteredParticipants.map((participant, index) => (
               <button
                 key={participant.id}
                 onClick={() => addParticipant(participant)}
-                className="w-full px-4 py-3 flex items-center gap-3 hover:bg-accent transition-colors text-left"
+                onMouseEnter={() => setHighlightedIndex(index)}
+                className={cn(
+                  "w-full px-4 py-3 flex items-center gap-3 hover:bg-accent transition-colors text-left",
+                  index === highlightedIndex && "bg-accent"
+                )}
               >
                 <div
                   className="w-8 h-8 rounded-full flex items-center justify-center text-xs font-medium text-white"
@@ -77,56 +181,33 @@ export const ParticipantSelector = ({
                   <div className="font-medium text-foreground">{participant.name}</div>
                   <div className="text-xs text-muted-foreground">{participant.email}</div>
                 </div>
-                {!participant.icsLink && (
-                  <span className="ml-auto text-xs text-amber-600 flex items-center gap-1">
-                    <AlertCircle className="w-3 h-3" />
-                    No calendar
-                  </span>
-                )}
+                <span className="ml-auto text-xs flex items-center gap-1">
+                  {participant.icsLink ? (
+                    <TooltipProvider>
+                      <Tooltip>
+                        <TooltipTrigger asChild>
+                          <span className="text-muted-foreground cursor-help flex items-center gap-1">
+                            📅 {getCalendarNameFromUrl(participant.icsLink) || 'Calendar'}
+                            <Info className="w-3 h-3 opacity-50" />
+                          </span>
+                        </TooltipTrigger>
+                        <TooltipContent side="left" className="max-w-[220px]">
+                          <p>Availability is based on this calendar only. Other calendars on the same account are not included.</p>
+                        </TooltipContent>
+                      </Tooltip>
+                    </TooltipProvider>
+                  ) : (
+                    <span className="text-amber-600 flex items-center gap-1">
+                      <AlertCircle className="w-3 h-3" />
+                      No calendar
+                    </span>
+                  )}
+                </span>
               </button>
             ))}
           </div>
         )}
       </div>
-
-      {selectedParticipants.length > 0 && (
-        <div className="flex flex-wrap gap-2">
-          {selectedParticipants.map((participant, index) => (
-            <div
-              key={participant.id}
-              className={cn(
-                "flex items-center gap-2 bg-accent text-accent-foreground px-3 py-2 rounded-full text-sm animate-scale-in",
-                "border border-primary/20"
-              )}
-              style={{ animationDelay: `${index * 50}ms` }}
-            >
-              <div
-                className="w-6 h-6 rounded-full flex items-center justify-center text-xs font-medium text-white"
-                style={{ backgroundColor: getAvatarColor(participant.name) }}
-              >
-                {getInitials(participant.name)}
-              </div>
-              <span className="font-medium">{participant.name.split(' ')[0]}</span>
-              {!participant.icsLink && (
-                <AlertCircle className="w-3 h-3 text-amber-600" title="No calendar linked" />
-              )}
-              <button
-                onClick={() => removeParticipant(participant.id)}
-                className="w-5 h-5 rounded-full hover:bg-primary/20 flex items-center justify-center transition-colors"
-              >
-                <X className="w-3 h-3" />
-              </button>
-            </div>
-          ))}
-          <button
-            onClick={() => setIsDropdownOpen(true)}
-            className="flex items-center gap-1 px-3 py-2 rounded-full text-sm border-2 border-dashed border-border text-muted-foreground hover:border-primary hover:text-primary transition-colors"
-          >
-            <Plus className="w-4 h-4" />
-            <span>Add</span>
-          </button>
-        </div>
-      )}
     </div>
   );
 };

frontend/src/components/ScheduleModal.tsx

@@ -11,30 +11,88 @@ import { Button } from '@/components/ui/button';
 import { Input } from '@/components/ui/input';
 import { Textarea } from '@/components/ui/textarea';
 import { Label } from '@/components/ui/label';
+import {
+  Select,
+  SelectContent,
+  SelectItem,
+  SelectTrigger,
+  SelectValue,
+} from '@/components/ui/select';
 import { toast } from '@/hooks/use-toast';
 import { Calendar, Clock, Users, Send, AlertCircle } from 'lucide-react';
 
+const DURATION_OPTIONS = [
+  { value: 15, label: '15 minutes' },
+  { value: 30, label: '30 minutes' },
+  { value: 45, label: '45 minutes' },
+  { value: 60, label: '1 hour' },
+  { value: 90, label: '1 hour 30 minutes' },
+  { value: 120, label: '2 hours' },
+  { value: 150, label: '2 hours 30 minutes' },
+];
+
 interface ScheduleModalProps {
   isOpen: boolean;
   onClose: () => void;
   slot: TimeSlot | null;
   participants: Participant[];
+  displayTimezone?: string;
+  onSuccess?: () => void;
 }
 
+// Get user's local timezone
+const getUserTimezone = (): string => {
+  try {
+    return Intl.DateTimeFormat().resolvedOptions().timeZone;
+  } catch {
+    return 'America/Toronto';
+  }
+};
+
+// Format timezone for display (e.g., "America/Toronto" -> "EST")
+const getTimezoneAbbrev = (timezone: string): string => {
+  try {
+    const now = new Date();
+    const formatter = new Intl.DateTimeFormat('en-US', {
+      timeZone: timezone,
+      timeZoneName: 'short',
+    });
+    const parts = formatter.formatToParts(now);
+    return parts.find((p) => p.type === 'timeZoneName')?.value || '';
+  } catch {
+    return '';
+  }
+};
+
 export const ScheduleModal = ({
   isOpen,
   onClose,
   slot,
   participants,
+  displayTimezone = getUserTimezone(),
+  onSuccess,
 }: ScheduleModalProps) => {
   const [title, setTitle] = useState('');
   const [notes, setNotes] = useState('');
+  const [duration, setDuration] = useState(60); // default 1 hour
   const [isSubmitting, setIsSubmitting] = useState(false);
 
   const formatHour = (hour: number) => {
     return `${hour.toString().padStart(2, '0')}:00`;
   };
 
+  const formatTime = (hour: number, minutes: number) => {
+    const totalMinutes = hour * 60 + minutes;
+    const h = Math.floor(totalMinutes / 60) % 24;
+    const m = totalMinutes % 60;
+    return `${h.toString().padStart(2, '0')}:${m.toString().padStart(2, '0')}`;
+  };
+
+  const getEndTime = () => {
+    if (!slot) return '';
+    return formatTime(slot.hour, duration);
+  };
+
   const formatDate = (dateStr: string) => {
     const date = new Date(dateStr + 'T00:00:00');
     return date.toLocaleDateString('en-US', { weekday: 'short', month: 'short', day: 'numeric' });
@@ -68,7 +126,7 @@ export const ScheduleModal = ({
       // Calculate start and end times
       // slot.day is YYYY-MM-DD
       const startDateTime = new Date(`${slot.day}T${formatHour(slot.hour)}:00Z`);
-      const endDateTime = new Date(`${slot.day}T${formatHour(slot.hour + 1)}:00Z`);
+      const endDateTime = new Date(startDateTime.getTime() + duration * 60 * 1000);
 
       await scheduleMeeting(
         participants.map(p => p.id),
@@ -86,6 +144,7 @@ export const ScheduleModal = ({
       setTitle('');
       setNotes('');
       onClose();
+      onSuccess?.();
     } catch (error) {
       toast({
         title: "Scheduling failed",
@@ -115,7 +174,7 @@ export const ScheduleModal = ({
             </div>
             <div className="flex items-center gap-3 text-sm">
               <Clock className="w-4 h-4 text-primary" />
-              <span>{formatHour(slot.hour)} – {formatHour(slot.hour + 1)}</span>
+              <span><span className="text-primary font-medium">{formatHour(slot.hour)} – {getEndTime()}</span> <span className="text-muted-foreground">({getTimezoneAbbrev(displayTimezone)})</span></span>
             </div>
             <div className="flex items-center gap-3 text-sm">
               <Users className="w-4 h-4 text-primary" />
@@ -125,6 +184,25 @@ export const ScheduleModal = ({
 
           {/* Form */}
           <div className="space-y-4">
+            <div className="space-y-2">
+              <Label htmlFor="duration">Duration</Label>
+              <Select
+                value={duration.toString()}
+                onValueChange={(value) => setDuration(Number(value))}
+              >
+                <SelectTrigger className="h-12">
+                  <SelectValue />
+                </SelectTrigger>
+                <SelectContent>
+                  {DURATION_OPTIONS.map((option) => (
+                    <SelectItem key={option.value} value={option.value.toString()}>
+                      {option.label}
+                    </SelectItem>
+                  ))}
+                </SelectContent>
+              </Select>
+            </div>
+
             <div className="space-y-2">
               <Label htmlFor="title">Meeting Title</Label>
               <Input

frontend/src/components/TimezoneSelector.tsx

@@ -11,11 +11,12 @@ interface TimezoneSelectorProps {
 
 // Get all IANA timezones
 const getAllTimezones = (): string[] => {
+  let timezones: string[] = [];
   try {
-    return Intl.supportedValuesOf('timeZone');
+    timezones = Intl.supportedValuesOf('timeZone');
   } catch {
     // Fallback for older browsers
-    return [
+    timezones = [
       'UTC',
       'America/New_York',
       'America/Chicago',
@@ -23,6 +24,7 @@ const getAllTimezones = (): string[] => {
       'America/Los_Angeles',
       'America/Toronto',
       'America/Vancouver',
+      'America/Montreal',
       'Europe/London',
       'Europe/Paris',
       'Europe/Berlin',
@@ -33,6 +35,17 @@ const getAllTimezones = (): string[] => {
       'Pacific/Auckland',
     ];
   }
+
+  // Prioritize Montreal as requested
+  const priorityTimezone = 'America/Montreal';
+  if (!timezones.includes(priorityTimezone)) {
+    timezones.push(priorityTimezone);
+  }
+
+  return [
+    priorityTimezone,
+    ...timezones.filter((tz) => tz !== priorityTimezone),
+  ];
 };
 
 // Get UTC offset for a timezone
@@ -158,7 +171,7 @@ export const TimezoneSelector = ({
                 No timezones found
               </div>
             ) : (
-              filteredTimezones.slice(0, 50).map((timezone) => {
+              filteredTimezones.map((timezone) => {
                 const isSelected = timezone === value;
                 const offset = getTimezoneOffset(timezone);
                 const label = formatTimezoneLabel(timezone);
@@ -204,12 +217,6 @@ export const TimezoneSelector = ({
               })
             )}
           </div>
-
-          {filteredTimezones.length > 50 && (
-            <div className="px-4 py-2 text-xs text-muted-foreground text-center border-t border-border">
-              Showing 50 of {filteredTimezones.length} results
-            </div>
-          )}
         </div>
       )}
     </div>

frontend/src/components/ui/sheet.tsx

@@ -1,17 +1,17 @@
-import * as SheetPrimitive from "@radix-ui/react-dialog";
-import { cva, type VariantProps } from "class-variance-authority";
-import { X } from "lucide-react";
-import * as React from "react";
+import * as React from "react"
+import * as SheetPrimitive from "@radix-ui/react-dialog"
+import { cva, type VariantProps } from "class-variance-authority"
+import { X } from "lucide-react"
 
-import { cn } from "@/lib/utils";
+import { cn } from "@/lib/utils"
 
-const Sheet = SheetPrimitive.Root;
+const Sheet = SheetPrimitive.Root
 
-const SheetTrigger = SheetPrimitive.Trigger;
+const SheetTrigger = SheetPrimitive.Trigger
 
-const SheetClose = SheetPrimitive.Close;
+const SheetClose = SheetPrimitive.Close
 
-const SheetPortal = SheetPrimitive.Portal;
+const SheetPortal = SheetPrimitive.Portal
 
 const SheetOverlay = React.forwardRef<
   React.ElementRef<typeof SheetPrimitive.Overlay>,
@@ -19,14 +19,14 @@ const SheetOverlay = React.forwardRef<
 >(({ className, ...props }, ref) => (
   <SheetPrimitive.Overlay
     className={cn(
-      "fixed inset-0 z-50 bg-black/80 data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0",
-      className,
+      "fixed inset-0 z-50 bg-black/80  data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0",
+      className
     )}
     {...props}
     ref={ref}
   />
-));
-SheetOverlay.displayName = SheetPrimitive.Overlay.displayName;
+))
+SheetOverlay.displayName = SheetPrimitive.Overlay.displayName
 
 const sheetVariants = cva(
   "fixed z-50 gap-4 bg-background p-6 shadow-lg transition ease-in-out data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:duration-300 data-[state=open]:duration-500",
@@ -38,70 +38,101 @@ const sheetVariants = cva(
           "inset-x-0 bottom-0 border-t data-[state=closed]:slide-out-to-bottom data-[state=open]:slide-in-from-bottom",
         left: "inset-y-0 left-0 h-full w-3/4 border-r data-[state=closed]:slide-out-to-left data-[state=open]:slide-in-from-left sm:max-w-sm",
         right:
-          "inset-y-0 right-0 h-full w-3/4  border-l data-[state=closed]:slide-out-to-right data-[state=open]:slide-in-from-right sm:max-w-sm",
+          "inset-y-0 right-0 h-full w-3/4 border-l data-[state=closed]:slide-out-to-right data-[state=open]:slide-in-from-right sm:max-w-sm",
       },
     },
     defaultVariants: {
       side: "right",
     },
-  },
-);
+  }
+)
 
 interface SheetContentProps
   extends React.ComponentPropsWithoutRef<typeof SheetPrimitive.Content>,
-    VariantProps<typeof sheetVariants> {}
+  VariantProps<typeof sheetVariants> { }
 
-const SheetContent = React.forwardRef<React.ElementRef<typeof SheetPrimitive.Content>, SheetContentProps>(
-  ({ side = "right", className, children, ...props }, ref) => (
-    <SheetPortal>
-      <SheetOverlay />
-      <SheetPrimitive.Content ref={ref} className={cn(sheetVariants({ side }), className)} {...props}>
-        {children}
-        <SheetPrimitive.Close className="absolute right-4 top-4 rounded-sm opacity-70 ring-offset-background transition-opacity data-[state=open]:bg-secondary hover:opacity-100 focus:outline-none focus:ring-2 focus:ring-ring focus:ring-offset-2 disabled:pointer-events-none">
-          <X className="h-4 w-4" />
-          <span className="sr-only">Close</span>
-        </SheetPrimitive.Close>
-      </SheetPrimitive.Content>
-    </SheetPortal>
-  ),
-);
-SheetContent.displayName = SheetPrimitive.Content.displayName;
+const SheetContent = React.forwardRef<
+  React.ElementRef<typeof SheetPrimitive.Content>,
+  SheetContentProps
+>(({ side = "right", className, children, ...props }, ref) => (
+  <SheetPortal>
+    <SheetOverlay />
+    <SheetPrimitive.Content
+      ref={ref}
+      className={cn(sheetVariants({ side }), className)}
+      {...props}
+    >
+      {children}
+      <SheetPrimitive.Close className="absolute right-4 top-4 rounded-sm opacity-70 ring-offset-background transition-opacity hover:opacity-100 focus:outline-none focus:ring-2 focus:ring-ring focus:ring-offset-2 disabled:pointer-events-none data-[state=open]:bg-secondary">
+        <X className="h-4 w-4" />
+        <span className="sr-only">Close</span>
+      </SheetPrimitive.Close>
+    </SheetPrimitive.Content>
+  </SheetPortal>
+))
+SheetContent.displayName = SheetPrimitive.Content.displayName
 
-const SheetHeader = ({ className, ...props }: React.HTMLAttributes<HTMLDivElement>) => (
-  <div className={cn("flex flex-col space-y-2 text-center sm:text-left", className)} {...props} />
-);
-SheetHeader.displayName = "SheetHeader";
+const SheetHeader = ({
+  className,
+  ...props
+}: React.HTMLAttributes<HTMLDivElement>) => (
+  <div
+    className={cn(
+      "flex flex-col space-y-2 text-center sm:text-left",
+      className
+    )}
+    {...props}
+  />
+)
+SheetHeader.displayName = "SheetHeader"
 
-const SheetFooter = ({ className, ...props }: React.HTMLAttributes<HTMLDivElement>) => (
-  <div className={cn("flex flex-col-reverse sm:flex-row sm:justify-end sm:space-x-2", className)} {...props} />
-);
-SheetFooter.displayName = "SheetFooter";
+const SheetFooter = ({
+  className,
+  ...props
+}: React.HTMLAttributes<HTMLDivElement>) => (
+  <div
+    className={cn(
+      "flex flex-col-reverse sm:flex-row sm:justify-end sm:space-x-2",
+      className
+    )}
+    {...props}
+  />
+)
+SheetFooter.displayName = "SheetFooter"
 
 const SheetTitle = React.forwardRef<
   React.ElementRef<typeof SheetPrimitive.Title>,
   React.ComponentPropsWithoutRef<typeof SheetPrimitive.Title>
 >(({ className, ...props }, ref) => (
-  <SheetPrimitive.Title ref={ref} className={cn("text-lg font-semibold text-foreground", className)} {...props} />
-));
-SheetTitle.displayName = SheetPrimitive.Title.displayName;
+  <SheetPrimitive.Title
+    ref={ref}
+    className={cn("text-lg font-semibold text-foreground", className)}
+    {...props}
+  />
+))
+SheetTitle.displayName = SheetPrimitive.Title.displayName
 
 const SheetDescription = React.forwardRef<
   React.ElementRef<typeof SheetPrimitive.Description>,
   React.ComponentPropsWithoutRef<typeof SheetPrimitive.Description>
 >(({ className, ...props }, ref) => (
-  <SheetPrimitive.Description ref={ref} className={cn("text-sm text-muted-foreground", className)} {...props} />
-));
-SheetDescription.displayName = SheetPrimitive.Description.displayName;
+  <SheetPrimitive.Description
+    ref={ref}
+    className={cn("text-sm text-muted-foreground", className)}
+    {...props}
+  />
+))
+SheetDescription.displayName = SheetPrimitive.Description.displayName
 
 export {
   Sheet,
+  SheetPortal,
+  SheetOverlay,
+  SheetTrigger,
   SheetClose,
   SheetContent,
-  SheetDescription,
-  SheetFooter,
   SheetHeader,
-  SheetOverlay,
-  SheetPortal,
+  SheetFooter,
   SheetTitle,
-  SheetTrigger,
-};
+  SheetDescription,
+}

frontend/src/index.css

@@ -111,10 +111,51 @@
     --sidebar-ring: 18 68% 51%;
   }
 
-  /* Dark mode intentionally removed/reset to match light mode system for now, 
-     or you can define a proper dark mode if required. 
-     Keeping it simple as per previous apps. */
-}
+    /* Dark mode */
+    .dark {
+      --background: 60 5% 8%;   /* #161614 */
+      --foreground: 60 9% 93%;  /* #F0F0EC */
+
+      --card: 60 5% 10%;        /* Slightly lighter than bg */
+      --card-foreground: 60 9% 93%;
+
+      --popover: 60 5% 10%;
+      --popover-foreground: 60 9% 93%;
+
+      --primary: 18 68% 51%;    /* Keep primary brand color */
+      --primary-foreground: 60 9% 97%;
+
+      --secondary: 60 5% 15%;
+      --secondary-foreground: 60 9% 93%;
+
+      --muted: 60 5% 15%;
+      --muted-foreground: 60 5% 65%;
+
+      --accent: 60 5% 15%;
+      --accent-foreground: 60 9% 93%;
+
+      --destructive: 0 62% 30%;
+      --destructive-foreground: 60 9% 97%;
+
+      --border: 60 5% 20%;
+      --input: 60 5% 20%;
+      --ring: 18 68% 51%;
+
+      /* Dark mode availability colors */
+      --availability-full: 142 70% 45%;    /* Brighter green for dark mode */
+      --availability-partial: 25 80% 65%;  /* Same orange */
+      --availability-none: 60 5% 20%;      /* Darker grey */
+      
+      --sidebar-background: 60 5% 8%;
+      --sidebar-foreground: 60 9% 93%;
+      --sidebar-primary: 18 68% 51%;
+      --sidebar-primary-foreground: 60 9% 97%;
+      --sidebar-accent: 60 5% 15%;
+      --sidebar-accent-foreground: 60 9% 93%;
+      --sidebar-border: 60 5% 20%;
+      --sidebar-ring: 18 68% 51%;
+    }
+  }
 
 @layer base {
   * {
@@ -192,3 +233,15 @@
   0%, 100% { opacity: 1; }
   50% { opacity: 0.7; }
 }
+
+.pattern-diagonal-lines {
+  background-image: repeating-linear-gradient(
+    45deg,
+    currentColor,
+    currentColor 1px,
+    transparent 1px,
+    transparent 10px
+  );
+  background-size: 10px 10px;
+  opacity: 0.1;
+}

frontend/src/lib/utils.ts

@@ -5,6 +5,20 @@ export function cn(...inputs: ClassValue[]) {
   return twMerge(clsx(inputs));
 }
 
+export function getCalendarNameFromUrl(icsUrl: string | null | undefined): string | null {
+  if (!icsUrl) return null;
+  try {
+    const url = new URL(icsUrl);
+    const pathname = url.pathname;
+    const filename = pathname.split('/').pop() || '';
+    // Decode URL encoding (e.g., %20 -> space) and remove .ics extension
+    const decoded = decodeURIComponent(filename).replace(/\.ics$/i, '');
+    return decoded || null;
+  } catch {
+    return null;
+  }
+}
+
 export function getAvatarColor(name?: string): string {
   const colors = [
     'hsl(var(--tag-green))',

frontend/src/pages/Index.tsx

@@ -4,7 +4,9 @@ import { Header } from '@/components/Header';
 import { ParticipantSelector } from '@/components/ParticipantSelector';
 import { ParticipantManager } from '@/components/ParticipantManager';
 import { AvailabilityHeatmap } from '@/components/AvailabilityHeatmap';
+import { AvailabilityHeatmapV2 } from '@/components/AvailabilityHeatmapV2';
 import { ScheduleModal } from '@/components/ScheduleModal';
+import { TimezoneSelector } from '@/components/TimezoneSelector';
 import { Participant, TimeSlot } from '@/types/calendar';
 import { Tabs, TabsContent, TabsList, TabsTrigger } from '@/components/ui/tabs';
 import { Switch } from '@/components/ui/switch';
@@ -14,6 +16,22 @@ import {
   PopoverContent,
   PopoverTrigger,
 } from '@/components/ui/popover';
+import {
+  Sheet,
+  SheetContent,
+  SheetTrigger,
+} from '@/components/ui/sheet';
+import {
+  AlertDialog,
+  AlertDialogAction,
+  AlertDialogCancel,
+  AlertDialogContent,
+  AlertDialogDescription,
+  AlertDialogFooter,
+  AlertDialogHeader,
+  AlertDialogTitle,
+  AlertDialogTrigger,
+} from '@/components/ui/alert-dialog';
 import { Button } from '@/components/ui/button';
 import { Users, CalendarDays, Settings, RefreshCw } from 'lucide-react';
 import { useToast } from '@/hooks/use-toast';
@@ -24,17 +42,33 @@ import {
   deleteParticipant,
   fetchAvailability,
   syncCalendars,
+  clearAllBookings,
   ParticipantAPI,
 } from '@/api/client';
 
 const SETTINGS_KEY = 'calendar-settings';
 
+// Get user's local timezone
+const getUserTimezone = (): string => {
+  try {
+    return Intl.DateTimeFormat().resolvedOptions().timeZone;
+  } catch {
+    return 'America/Toronto';
+  }
+};
+
 interface SettingsState {
   showPartialAvailability: boolean;
+  displayTimezone: string;
+  showSecondaryTimezone: boolean;
+  secondaryTimezone: string;
 }
 
 const defaultSettings: SettingsState = {
   showPartialAvailability: false,
+  displayTimezone: getUserTimezone(),
+  showSecondaryTimezone: true,
+  secondaryTimezone: 'America/Montreal', // Company timezone as default secondary
 };
 
 function apiToParticipant(p: ParticipantAPI): Participant {
@@ -61,7 +95,9 @@ const Index = ({ defaultTab = 'schedule' }: IndexProps) => {
   const [availabilitySlots, setAvailabilitySlots] = useState<TimeSlot[]>([]);
   const [selectedSlot, setSelectedSlot] = useState<TimeSlot | null>(null);
   const [isModalOpen, setIsModalOpen] = useState(false);
+  const [useRedesign, setUseRedesign] = useState(true);
   const [settings, setSettings] = useState<SettingsState>(defaultSettings);
+  const [weekOffset, setWeekOffset] = useState(0);
   const [isLoading, setIsLoading] = useState(false);
   const [isSyncing, setIsSyncing] = useState(false);
   const { toast } = useToast();
@@ -101,7 +137,7 @@ const Index = ({ defaultTab = 'schedule' }: IndexProps) => {
     } else {
       setAvailabilitySlots([]);
     }
-  }, [selectedParticipants]);
+  }, [selectedParticipants, weekOffset]);
 
   const loadParticipants = async () => {
     try {
@@ -120,7 +156,7 @@ const Index = ({ defaultTab = 'schedule' }: IndexProps) => {
     setIsLoading(true);
     try {
       const ids = selectedParticipants.map((p) => p.id);
-      const slots = await fetchAvailability(ids);
+      const slots = await fetchAvailability(ids, weekOffset);
       setAvailabilitySlots(slots);
     } catch (error) {
       toast({
@@ -209,6 +245,25 @@ const Index = ({ defaultTab = 'schedule' }: IndexProps) => {
     setIsModalOpen(true);
   };
 
+  const handleClearBookings = async () => {
+    try {
+      await clearAllBookings();
+      if (selectedParticipants.length > 0) {
+        await loadAvailability();
+      }
+      toast({
+        title: 'Bookings cleared',
+        description: 'All scheduled meetings have been removed',
+      });
+    } catch (error) {
+      toast({
+        title: 'Error clearing bookings',
+        description: error instanceof Error ? error.message : 'Unknown error',
+        variant: 'destructive',
+      });
+    }
+  };
+
   return (
     <div className="min-h-screen bg-background">
       <Header />
@@ -254,6 +309,10 @@ const Index = ({ defaultTab = 'schedule' }: IndexProps) => {
             <div className="space-y-8">
               <div className="text-center relative">
                 <div className="absolute right-0 top-0 flex items-center gap-2">
+                  <TimezoneSelector
+                    value={settings.displayTimezone}
+                    onChange={(tz) => setSettings((prev) => ({ ...prev, displayTimezone: tz }))}
+                  />
                   <Button
                     variant="ghost"
                     size="icon"
@@ -262,33 +321,114 @@ const Index = ({ defaultTab = 'schedule' }: IndexProps) => {
                   >
                     <RefreshCw className={`w-5 h-5 ${isSyncing ? 'animate-spin' : ''}`} />
                   </Button>
-                  <Popover>
-                    <PopoverTrigger asChild>
+                  <Sheet>
+                    <SheetTrigger asChild>
                       <Button variant="ghost" size="icon">
                         <Settings className="w-5 h-5" />
                       </Button>
-                    </PopoverTrigger>
-                    <PopoverContent className="w-72" align="end">
-                      <div className="space-y-4">
-                        <h4 className="font-medium">Settings</h4>
-                        <div className="flex items-center justify-between gap-4">
-                          <Label htmlFor="partial-availability" className="text-sm cursor-pointer">
-                            Show partial availability
-                          </Label>
-                          <Switch
-                            id="partial-availability"
-                            checked={settings.showPartialAvailability}
-                            onCheckedChange={(checked) =>
-                              setSettings((prev) => ({ ...prev, showPartialAvailability: checked }))
-                            }
-                          />
+                    </SheetTrigger>
+                    <SheetContent side="right" className="w-[300px] sm:w-[350px]">
+                      <div className="space-y-6 py-4">
+                        <div className="space-y-2">
+                          <h4 className="font-semibold text-lg tracking-tight">Settings</h4>
+                          <p className="text-sm text-muted-foreground">
+                            Configure your calendar preferences.
+                          </p>
+                        </div>
+
+                        <div className="space-y-4">
+                          <div className="flex items-center justify-between gap-4 pb-4 border-b border-border">
+                            <Label htmlFor="use-redesign" className="text-sm cursor-pointer font-medium text-primary">
+                              Try New Design
+                            </Label>
+                            <Switch
+                              id="use-redesign"
+                              checked={useRedesign}
+                              onCheckedChange={setUseRedesign}
+                            />
+                          </div>
+
+                          <div className="flex items-center justify-between gap-4">
+                            <div className="space-y-0.5">
+                              <Label htmlFor="partial-availability" className="text-sm font-medium cursor-pointer">
+                                Partial Availability
+                              </Label>
+                              <p className="text-xs text-muted-foreground">
+                                Show slots where some are busy
+                              </p>
+                            </div>
+                            <Switch
+                              id="partial-availability"
+                              checked={settings.showPartialAvailability}
+                              onCheckedChange={(checked) =>
+                                setSettings((prev) => ({ ...prev, showPartialAvailability: checked }))
+                              }
+                            />
+                          </div>
+
+                          <div className="border-t border-border pt-4 space-y-4">
+                            <div className="flex items-center justify-between gap-4">
+                              <Label htmlFor="secondary-timezone" className="text-sm cursor-pointer">
+                                Show secondary timezone
+                              </Label>
+                              <Switch
+                                id="secondary-timezone"
+                                checked={settings.showSecondaryTimezone}
+                                onCheckedChange={(checked) =>
+                                  setSettings((prev) => ({ ...prev, showSecondaryTimezone: checked }))
+                                }
+                              />
+                            </div>
+                            {settings.showSecondaryTimezone && (
+                              <div className="space-y-2">
+                                <Label className="text-xs text-muted-foreground block">
+                                  Secondary timezone
+                                </Label>
+                                <TimezoneSelector
+                                  value={settings.secondaryTimezone}
+                                  onChange={(tz) => setSettings((prev) => ({ ...prev, secondaryTimezone: tz }))}
+                                />
+                              </div>
+                            )}
+                          </div>
+
+                          <div className="border-t border-border pt-4 mt-8">
+                            <Label className="text-xs font-semibold text-muted-foreground uppercase tracking-wider mb-3 block">
+                              Danger Zone
+                            </Label>
+                            <AlertDialog>
+                              <AlertDialogTrigger asChild>
+                                <Button
+                                  variant="outline"
+                                  size="sm"
+                                  className="text-destructive hover:text-destructive-foreground hover:bg-destructive border-destructive/30"
+                                >
+                                  Clear All Bookings
+                                </Button>
+                              </AlertDialogTrigger>
+                              <AlertDialogContent>
+                                <AlertDialogHeader>
+                                  <AlertDialogTitle>Clear all bookings?</AlertDialogTitle>
+                                  <AlertDialogDescription>
+                                    This will remove all scheduled meetings. This cannot be undone.
+                                  </AlertDialogDescription>
+                                </AlertDialogHeader>
+                                <AlertDialogFooter>
+                                  <AlertDialogCancel>Cancel</AlertDialogCancel>
+                                  <AlertDialogAction
+                                    onClick={handleClearBookings}
+                                    className="bg-destructive text-destructive-foreground hover:bg-destructive/90"
+                                  >
+                                    Clear All
+                                  </AlertDialogAction>
+                                </AlertDialogFooter>
+                              </AlertDialogContent>
+                            </AlertDialog>
+                          </div>
                         </div>
-                        <p className="text-xs text-muted-foreground">
-                          When enabled, shows time slots where only some participants are available.
-                        </p>
                       </div>
-                    </PopoverContent>
-                  </Popover>
+                    </SheetContent>
+                  </Sheet>
                 </div>
                 <h2 className="text-3xl font-bold text-foreground mb-2">
                   Schedule a Meeting
@@ -319,19 +459,39 @@ const Index = ({ defaultTab = 'schedule' }: IndexProps) => {
                     />
                   </div>
 
-                  <AvailabilityHeatmap
-                    slots={availabilitySlots}
-                    selectedParticipants={selectedParticipants}
-                    onSlotSelect={handleSlotSelect}
-                    showPartialAvailability={settings.showPartialAvailability}
-                    isLoading={isLoading}
-                  />
+                  {useRedesign ? (
+                    <AvailabilityHeatmapV2
+                      slots={availabilitySlots}
+                      selectedParticipants={selectedParticipants}
+                      onSlotSelect={handleSlotSelect}
+                      showPartialAvailability={settings.showPartialAvailability}
+                      isLoading={isLoading}
+                      weekOffset={weekOffset}
+                      onWeekOffsetChange={setWeekOffset}
+                      displayTimezone={settings.displayTimezone}
+                      showSecondaryTimezone={settings.showSecondaryTimezone}
+                      secondaryTimezone={settings.secondaryTimezone}
+                    />
+                  ) : (
+                    <AvailabilityHeatmap
+                      slots={availabilitySlots}
+                      selectedParticipants={selectedParticipants}
+                      onSlotSelect={handleSlotSelect}
+                      showPartialAvailability={settings.showPartialAvailability}
+                      isLoading={isLoading}
+                      weekOffset={weekOffset}
+                      onWeekOffsetChange={setWeekOffset}
+                      displayTimezone={settings.displayTimezone}
+                      showSecondaryTimezone={settings.showSecondaryTimezone}
+                      secondaryTimezone={settings.secondaryTimezone}
+                    />
+                  )}
                 </>
               )}
             </div>
           </TabsContent>
         </Tabs>
-      </main>
+      </main >
 
       <ScheduleModal
         isOpen={isModalOpen}
@@ -341,8 +501,10 @@ const Index = ({ defaultTab = 'schedule' }: IndexProps) => {
         }}
         slot={selectedSlot}
         participants={selectedParticipants}
+        displayTimezone={settings.displayTimezone}
+        onSuccess={loadAvailability}
       />
-    </div>
+    </div >
   );
 };