update

backend/src/app/availability_service.py

@@ -4,6 +4,7 @@ from uuid import UUID
 from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
 
+from app.config import settings
 from app.models import BusyBlock, Participant
 
 
@@ -70,37 +71,41 @@ async def calculate_availability(
     participants = {p.id: p for p in participants_result.scalars().all()}
 
     days = ["Mon", "Tue", "Wed", "Thu", "Fri"]
-    hours = list(range(0, 24))
+    slot_interval = settings.slot_interval_minutes
+    slots_per_hour = 60 // slot_interval
     slots = []
 
     for day_offset, day_name in enumerate(days):
-        for hour in hours:
+        for hour in range(24):
-            slot_start = week_start + timedelta(days=day_offset, hours=hour)
+            for slot_idx in range(slots_per_hour):
-            slot_end = slot_start + timedelta(hours=1)
+                minute = slot_idx * slot_interval
+                slot_start = week_start + timedelta(days=day_offset, hours=hour, minutes=minute)
+                slot_end = slot_start + timedelta(minutes=slot_interval)
 
-            available_participants = []
+                available_participants = []
-            for pid in participant_ids:
+                for pid in participant_ids:
-                if is_participant_free(busy_map.get(pid, []), slot_start, slot_end):
+                    if is_participant_free(busy_map.get(pid, []), slot_start, slot_end):
-                    participant = participants.get(pid)
+                        participant = participants.get(pid)
-                    if participant:
+                        if participant:
-                        available_participants.append(participant.name)
+                            available_participants.append(participant.name)
 
-            total = len(participant_ids)
+                total = len(participant_ids)
-            available_count = len(available_participants)
+                available_count = len(available_participants)
 
-            if available_count == total:
+                if available_count == total:
-                availability = "full"
+                    availability = "full"
-            elif available_count > 0:
+                elif available_count > 0:
-                availability = "partial"
+                    availability = "partial"
-            else:
+                else:
-                availability = "none"
+                    availability = "none"
 
-            slots.append({
+                slots.append({
-                "day": slot_start.strftime("%Y-%m-%d"),
+                    "day": slot_start.strftime("%Y-%m-%d"),
-                "hour": hour,
+                    "hour": hour,
-                "start_time": slot_start,
+                    "minute": minute,
-                "availability": availability,
+                    "start_time": slot_start,
-                "availableParticipants": available_participants,
+                    "availability": availability,
-            })
+                    "availableParticipants": available_participants,
+                })
 
     return slots

backend/src/app/config.py

@@ -5,6 +5,7 @@ class Settings(BaseSettings):
     database_url: str = "postgresql+asyncpg://postgres:postgres@db:5432/availability"
     sync_database_url: str = "postgresql://postgres:postgres@db:5432/availability"
     ics_refresh_interval_minutes: int = 15
+    slot_interval_minutes: int = 15  # Time slot granularity (15, 30, or 60)
 
     # SMTP Settings
     smtp_host: str | None = None

backend/src/app/zulip_service.py

@@ -61,7 +61,8 @@ def send_zulip_notification(
             f"📅 **Meeting Scheduled**\n"
             f"**What:** {title}\n"
             f"**When:** {zulip_time}\n"
-            f"**Who:** {people}"
+            f"**Who:** {people}\n"
+            f"*Booked via [Meetly](https://meetly.app.monadical.io/)*"
         )
 
         request = {

frontend/src/components/AvailabilityHeatmap.tsx

@@ -12,7 +12,14 @@ import { Check, X, Loader2, ChevronLeft, ChevronRight, ChevronsRight } from 'luc
 const DEFAULT_TIMEZONE = 'America/Toronto';
 
 const dayNames = ['Mon', 'Tue', 'Wed', 'Thu', 'Fri'];
-const hours = Array.from({ length: 24 }, (_, i) => i); // 0-23
+const SLOT_INTERVAL_MINUTES = 15;
+const SLOTS_PER_HOUR = 60 / SLOT_INTERVAL_MINUTES;
+
+// Generate time slots: [{hour: 0, minute: 0}, {hour: 0, minute: 30}, {hour: 1, minute: 0}, ...]
+const timeSlots = Array.from({ length: 24 * SLOTS_PER_HOUR }, (_, i) => ({
+  hour: Math.floor(i / SLOTS_PER_HOUR),
+  minute: (i % SLOTS_PER_HOUR) * SLOT_INTERVAL_MINUTES,
+}));
 
 // 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[] => {
@@ -46,11 +53,11 @@ const getWeekDates = (timezone: string, weekOffset: number = 0): string[] => {
   });
 };
 
-// Convert a date string and hour in a timezone to a UTC Date
+// Convert a date string, hour, and minute in a timezone to a UTC Date
-const toUTCDate = (dateStr: string, hour: number, timezone: string): Date => {
+const toUTCDate = (dateStr: string, hour: number, minute: number, timezone: string): Date => {
-  // Create a date string that represents the given hour in the given timezone
+  // Create a date string that represents the given time in the given timezone
   // Then parse it to get the UTC equivalent
-  const localDateStr = `${dateStr}T${String(hour).padStart(2, '0')}:00:00`;
+  const localDateStr = `${dateStr}T${String(hour).padStart(2, '0')}:${String(minute).padStart(2, '0')}:00`;
 
   // Use a trick: format in UTC then in target TZ to find the offset
   const testDate = new Date(localDateStr + 'Z'); // Treat as UTC first
@@ -111,29 +118,32 @@ const getTimezoneAbbrev = (timezone: string): string => {
   }
 };
 
-// Convert an hour from one timezone to another
+// Convert a time from one timezone to another
-const convertHourBetweenTimezones = (
+const convertTimeBetweenTimezones = (
   hour: number,
+  minute: number,
   dateStr: string,
   fromTimezone: string,
   toTimezone: string
-): number => {
+): { hour: number; minute: number } => {
   try {
-    // Create a UTC date for the given hour in the source timezone
+    // Create a UTC date for the given time in the source timezone
-    const utcDate = toUTCDate(dateStr, hour, fromTimezone);
+    const utcDate = toUTCDate(dateStr, hour, minute, fromTimezone);
 
-    // Format the hour in the target timezone
+    // Format the time in the target timezone
-    const targetHour = parseInt(
+    const formatter = new Intl.DateTimeFormat('en-US', {
-      new Intl.DateTimeFormat('en-US', {
+      timeZone: toTimezone,
-        timeZone: toTimezone,
+      hour: 'numeric',
-        hour: 'numeric',
+      minute: 'numeric',
-        hour12: false,
+      hour12: false,
-      }).format(utcDate)
+    });
-    );
+    const parts = formatter.formatToParts(utcDate);
+    const targetHour = parseInt(parts.find(p => p.type === 'hour')?.value || '0');
+    const targetMinute = parseInt(parts.find(p => p.type === 'minute')?.value || '0');
 
-    return targetHour;
+    return { hour: targetHour, minute: targetMinute };
   } catch {
-    return hour;
+    return { hour, minute };
   }
 };
 
@@ -216,24 +226,24 @@ export const AvailabilityHeatmap = ({
     const timer = setTimeout(() => {
       if (!scrollContainerRef.current) return;
 
-      const rowHeight = 52; // h-12 (48px) + gap (4px)
+      const rowHeight = 28; // h-6 (24px) + gap (4px)
-      const rowsAbove = 2;
+      const rowsAbove = 4; // Show a few slots before current time
 
-      // Calculate which hour should be at the top
+      // Calculate which slot should be at the top (multiply by slots per hour)
       const targetHour = todayIndex >= 0
-        ? Math.max(0, currentHour - rowsAbove)
+        ? Math.max(0, currentHour - Math.floor(rowsAbove / SLOTS_PER_HOUR))
         : 7; // Default to 7am for other weeks
 
-      scrollContainerRef.current.scrollTop = targetHour * rowHeight;
+      scrollContainerRef.current.scrollTop = targetHour * SLOTS_PER_HOUR * rowHeight;
     }, 100);
 
     return () => clearTimeout(timer);
   }, [weekOffset, todayIndex, currentHour, selectedParticipants.length, isLoading, slots.length]);
 
-  // Find a slot that matches the given display timezone date/hour
+  // Find a slot that matches the given display timezone date/hour/minute
-  const getSlot = (dateStr: string, hour: number): TimeSlot | undefined => {
+  const getSlot = (dateStr: string, hour: number, minute: number): TimeSlot | undefined => {
-    // Convert display timezone date/hour to UTC
+    // Convert display timezone date/hour/minute to UTC
-    const targetUTC = toUTCDate(dateStr, hour, displayTimezone);
+    const targetUTC = toUTCDate(dateStr, hour, minute, displayTimezone);
 
     return slots.find((s) => {
       const slotDate = new Date(s.start_time);
@@ -249,13 +259,13 @@ export const AvailabilityHeatmap = ({
     return slot.availability;
   };
 
-  const formatHour = (hour: number) => {
+  const formatTime = (hour: number, minute: number) => {
-    return `${hour.toString().padStart(2, '0')}:00`;
+    return `${hour.toString().padStart(2, '0')}:${minute.toString().padStart(2, '0')}`;
   };
 
-  const isSlotTooSoon = (dateStr: string, hour: number) => {
+  const isSlotTooSoon = (dateStr: string, hour: number, minute: number) => {
     // Convert to UTC and compare with current time
-    const slotTimeUTC = toUTCDate(dateStr, hour, displayTimezone);
+    const slotTimeUTC = toUTCDate(dateStr, hour, minute, displayTimezone);
     const now = new Date();
     const twoHoursFromNow = new Date(now.getTime() + 2 * 60 * 60 * 1000);
     return slotTimeUTC < twoHoursFromNow;
@@ -271,11 +281,11 @@ export const AvailabilityHeatmap = ({
     return `${format(monday)} – ${format(friday)}`;
   };
 
-  // Format hour for display in popover (in the display timezone)
+  // Format time for display in popover (in the display timezone)
-  const formatDisplayTime = (hour: number) => {
+  const formatDisplayTime = (hour: number, minute: number) => {
-    // Create a date at that hour
+    // Create a date at that time
     const date = new Date();
-    date.setHours(hour, 0, 0, 0);
+    date.setHours(hour, minute, 0, 0);
     return new Intl.DateTimeFormat('en-US', {
       hour: 'numeric',
       minute: '2-digit',
@@ -398,144 +408,152 @@ export const AvailabilityHeatmap = ({
           onScroll={handleScroll}
         >
           <div className="min-w-[600px]">
-          <div className={cn(
+            <div className={cn(
-            "grid gap-1 mb-2 sticky top-0 bg-card z-10",
+              "grid gap-1 mb-2 sticky top-0 bg-card z-10",
-            showSecondaryTimezone
+              showSecondaryTimezone
-              ? "grid-cols-[50px_50px_repeat(5,1fr)]"
+                ? "grid-cols-[50px_50px_repeat(5,1fr)]"
-              : "grid-cols-[60px_repeat(5,1fr)]"
+                : "grid-cols-[60px_repeat(5,1fr)]"
-          )}>
+            )}>
-            {showSecondaryTimezone ? (
+              {showSecondaryTimezone ? (
-              <>
+                <>
-                <div className="text-center text-xs font-medium text-primary py-2">
+                  <div className="text-center text-xs font-medium text-primary py-2">
-                  {getTimezoneAbbrev(displayTimezone)}
+                    {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}
+                  className="text-center text-sm font-medium text-muted-foreground py-2"
+                >
+                  <div>{dayName}</div>
+                  <div className="text-xs opacity-70">
+                    {weekDates[i]?.slice(5).replace('-', '/')}
+                  </div>
                 </div>
-                <div className="text-center text-xs font-medium text-muted-foreground py-2">
+              ))}
-                  {getTimezoneAbbrev(secondaryTimezone)}
+            </div>
-                </div>
-              </>
-            ) : (
-              <div></div>
-            )}
-            {dayNames.map((dayName, i) => (
-              <div
-                key={dayName}
-                className="text-center text-sm font-medium text-muted-foreground py-2"
-              >
-                <div>{dayName}</div>
-                <div className="text-xs opacity-70">
-                  {weekDates[i]?.slice(5).replace('-', '/')}
-                </div>
-              </div>
-            ))}
-          </div>
 
-          <div className="space-y-1">
+            <div className="space-y-1">
-            {hours.map((hour) => (
+              {timeSlots.map(({ hour, minute }) => (
-              <div
+                <div
-                key={hour}
+                  key={`${hour}-${minute}`}
-                ref={todayIndex >= 0 && hour === currentHour ? currentHourRef : undefined}
+                  ref={todayIndex >= 0 && hour === currentHour && minute === 0 ? currentHourRef : undefined}
-                className={cn(
+                  className={cn(
-                  "grid gap-1",
+                    "grid gap-1",
-                  showSecondaryTimezone
+                    showSecondaryTimezone
-                    ? "grid-cols-[50px_50px_repeat(5,1fr)]"
+                      ? "grid-cols-[50px_50px_repeat(5,1fr)]"
-                    : "grid-cols-[60px_repeat(5,1fr)]"
+                      : "grid-cols-[60px_repeat(5,1fr)]"
-                )}
+                  )}
-              >
+                >
-                {showSecondaryTimezone ? (
+                  {showSecondaryTimezone ? (
-                  <>
+                    <>
-                    <div className="text-xs text-primary font-medium flex items-center justify-center gap-1">
+                      <div className="text-xs text-primary font-medium flex items-center justify-center gap-1">
-                      {todayIndex >= 0 && hour === currentHour && (
+                        {todayIndex >= 0 && hour === currentHour && minute === 0 && (
+                          <span className="w-2 h-2 rounded-full bg-primary animate-pulse" />
+                        )}
+                        {formatTime(hour, minute)}
+                      </div>
+                      <div className="text-xs text-muted-foreground flex items-center justify-center">
+                        {(() => {
+                          const converted = convertTimeBetweenTimezones(hour, minute, weekDates[0] || '', displayTimezone, secondaryTimezone);
+                          return formatTime(converted.hour, converted.minute);
+                        })()}
+                      </div>
+                    </>
+                  ) : (
+                    <div className="text-xs text-muted-foreground flex items-center justify-end pr-3 gap-1">
+                      {todayIndex >= 0 && hour === currentHour && minute === 0 && (
                         <span className="w-2 h-2 rounded-full bg-primary animate-pulse" />
                       )}
-                      {formatHour(hour)}
+                      {formatTime(hour, minute)}
                     </div>
-                    <div className="text-xs text-muted-foreground flex items-center justify-center">
+                  )}
-                      {formatHour(convertHourBetweenTimezones(hour, weekDates[0] || '', displayTimezone, secondaryTimezone))}
+                  {weekDates.map((dateStr, dayIndex) => {
-                    </div>
+                    const slot = getSlot(dateStr, hour, minute);
-                  </>
+                    const dayName = dayNames[dayIndex];
-                ) : (
+                    const tooSoon = isSlotTooSoon(dateStr, hour, minute);
-                  <div className="text-xs text-muted-foreground flex items-center justify-end pr-3 gap-1">
+                    if (!slot) return <div key={`${dateStr}-${hour}-${minute}`} className="h-6 bg-muted rounded" />;
-                    {todayIndex >= 0 && hour === currentHour && (
-                      <span className="w-2 h-2 rounded-full bg-primary animate-pulse" />
-                    )}
-                    {formatHour(hour)}
-                  </div>
-                )}
-                {weekDates.map((dateStr, dayIndex) => {
-                  const slot = getSlot(dateStr, hour);
-                  const dayName = dayNames[dayIndex];
-                  const tooSoon = isSlotTooSoon(dateStr, hour);
-                  if (!slot) return <div key={`${dateStr}-${hour}`} className="h-12 bg-muted rounded" />;
 
-                  const effectiveAvailability = getEffectiveAvailability(slot);
+                    const effectiveAvailability = getEffectiveAvailability(slot);
 
-                  return (
+                    // Calculate end time for display
-                    <Popover key={`${dateStr}-${hour}`}>
+                    const endMinute = minute + SLOT_INTERVAL_MINUTES;
-                      <PopoverTrigger asChild>
+                    const endHour = hour + Math.floor(endMinute / 60);
-                        <button
+                    const endMinuteNormalized = endMinute % 60;
-                          className={cn(
+
-                            "h-12 rounded-md transition-all duration-200 focus:outline-none focus:ring-2 focus:ring-ring focus:ring-offset-2",
+                    return (
-                            tooSoon && "opacity-40 cursor-not-allowed",
+                      <Popover key={`${dateStr}-${hour}-${minute}`}>
-                            !tooSoon && "hover:scale-105 hover:shadow-md",
+                        <PopoverTrigger asChild>
-                            effectiveAvailability === 'full' && "bg-availability-full hover:bg-availability-full/90",
+                          <button
-                            effectiveAvailability === 'partial' && "bg-availability-partial hover:bg-availability-partial/90",
+                            className={cn(
-                            effectiveAvailability === 'none' && "bg-availability-none hover:bg-availability-none/90"
+                              "h-6 rounded-md transition-all duration-200 focus:outline-none focus:ring-2 focus:ring-ring focus:ring-offset-2",
-                          )}
+                              tooSoon && "opacity-40 cursor-not-allowed",
-                        />
+                              !tooSoon && "hover:scale-105 hover:shadow-md",
-                      </PopoverTrigger>
+                              effectiveAvailability === 'full' && "bg-availability-full hover:bg-availability-full/90",
-                      <PopoverContent className="w-64 p-4 animate-scale-in" align="center">
+                              effectiveAvailability === 'partial' && "bg-availability-partial hover:bg-availability-partial/90",
-                        <div className="space-y-3">
+                              effectiveAvailability === 'none' && "bg-availability-none hover:bg-availability-none/90"
-                          <div className="font-semibold text-foreground">
+                            )}
-                            {dayName} {formatDisplayTime(hour)}–{formatDisplayTime(hour + 1)}
+                          />
-                          </div>
+                        </PopoverTrigger>
-                          {tooSoon && (
+                        <PopoverContent className="w-64 p-4 animate-scale-in" align="center">
-                            <div className="text-sm text-muted-foreground italic">
+                          <div className="space-y-3">
-                              This time slot has passed or is too soon to schedule
+                            <div className="font-semibold text-foreground">
+                              {dayName} {formatDisplayTime(hour, minute)}–{formatDisplayTime(endHour, endMinuteNormalized)}
                             </div>
-                          )}
+                            {tooSoon && (
-                          <div className="space-y-2">
+                              <div className="text-sm text-muted-foreground italic">
-                            {selectedParticipants.map((participant) => {
+                                This time slot has passed or is too soon to schedule
-                              const isAvailable = slot.availableParticipants.includes(participant.name);
+                              </div>
+                            )}
+                            <div className="space-y-2">
+                              {selectedParticipants.map((participant) => {
+                                const isAvailable = slot.availableParticipants.includes(participant.name);
 
-                              return (
+                                return (
-                                <div
+                                  <div
-                                  key={participant.id}
+                                    key={participant.id}
-                                  className="flex items-center gap-2 text-sm"
+                                    className="flex items-center gap-2 text-sm"
-                                >
+                                  >
-                                  {isAvailable ? (
+                                    {isAvailable ? (
-                                    <Check className="w-4 h-4 text-availability-full" />
+                                      <Check className="w-4 h-4 text-availability-full" />
-                                  ) : (
+                                    ) : (
-                                    <X className="w-4 h-4 text-destructive" />
+                                      <X className="w-4 h-4 text-destructive" />
-                                  )}
+                                    )}
-                                  <span className={cn(
+                                    <span className={cn(
-                                    isAvailable ? "text-foreground" : "text-muted-foreground"
+                                      isAvailable ? "text-foreground" : "text-muted-foreground"
-                                  )}>
+                                    )}>
-                                    {participant.name.split(' ')[0]}
+                                      {participant.name.split(' ')[0]}
-                                  </span>
+                                    </span>
-                                </div>
+                                  </div>
-                              );
+                                );
-                            })}
+                              })}
+                            </div>
+                            {effectiveAvailability !== 'none' && !tooSoon && (
+                              <Button
+                                variant="schedule"
+                                className="w-full mt-2"
+                                onClick={() => onSlotSelect(slot)}
+                              >
+                                Schedule
+                              </Button>
+                            )}
                           </div>
-                          {effectiveAvailability !== 'none' && !tooSoon && (
+                        </PopoverContent>
-                            <Button
+                      </Popover>
-                              variant="schedule"
+                    );
-                              className="w-full mt-2"
+                  })}
-                              onClick={() => onSlotSelect(slot)}
+                </div>
-                            >
+              ))}
-                              Schedule
+            </div>
-                            </Button>
-                          )}
-                        </div>
-                      </PopoverContent>
-                    </Popover>
-                  );
-                })}
-              </div>
-            ))}
           </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 +1,499 @@
+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 SLOT_INTERVAL_MINUTES = 15;
+const SLOTS_PER_HOUR = 60 / SLOT_INTERVAL_MINUTES;
+const WORKING_HOUR_START = 8; // 8 AM
+const WORKING_HOUR_END = 18; // 6 PM
+
+// Generate time slots with hour and minute
+const ALL_TIME_SLOTS = Array.from({ length: 24 * SLOTS_PER_HOUR }, (_, i) => ({
+  hour: Math.floor(i / SLOTS_PER_HOUR),
+  minute: (i % SLOTS_PER_HOUR) * SLOT_INTERVAL_MINUTES,
+}));
+const WORKING_TIME_SLOTS = ALL_TIME_SLOTS.filter(
+  slot => slot.hour >= WORKING_HOUR_START && slot.hour < WORKING_HOUR_END
+);
+
+// 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 activeSlots = showFullDay ? ALL_TIME_SLOTS : WORKING_TIME_SLOTS;
+
+  const weekDates = useMemo(() => getWeekDates(displayTimezone, weekOffset), [displayTimezone, weekOffset]);
+
+  // Pre-compute slots lookup map for O(1) access
+  // Key: YYYY-MM-DD:Hour:Minute
+  const slotsMap = useMemo(() => {
+    const map = new Map<string, TimeSlot>();
+    slots.forEach(slot => {
+      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',
+        minute: 'numeric',
+        hour12: false
+      });
+      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;
+      const minute = parts.find(p => p.type === 'minute')?.value;
+
+      if (year && month && day && hour && minute) {
+        let h = parseInt(hour, 10);
+        let m = parseInt(minute, 10);
+        if (h === 24) h = 0; // Just in case
+
+        const key = `${year}-${month}-${day}:${h}:${m}`;
+        map.set(key, slot);
+      }
+    });
+    return map;
+  }, [slots, displayTimezone]);
+
+  const formatDateKey = (date: Date) => {
+    const y = date.getFullYear();
+    const m = String(date.getMonth() + 1).padStart(2, '0');
+    const d = String(date.getDate()).padStart(2, '0');
+    return `${y}-${m}-${d}`;
+  };
+
+  const formatDisplayDate = (date: Date) => {
+    return date.toLocaleDateString('en-US', { weekday: 'short', month: 'short', day: 'numeric' });
+  };
+
+  const getSlotForCell = (date: Date, hour: number, minute: number) => {
+    const key = `${formatDateKey(date)}:${hour}:${minute}`;
+    return slotsMap.get(key);
+  };
+
+  const formatTime = (hour: number, minute: number) => {
+    return new Date(0, 0, 0, hour, minute).toLocaleTimeString('en-US', {
+      hour: 'numeric',
+      minute: '2-digit',
+      hour12: true,
+    });
+  };
+
+  const formatHourOnly = (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">
+              {activeSlots.map(({ hour, minute }) => {
+                const isNight = hour < 8 || hour >= 18;
+
+                // Calculate secondary time
+                let secondaryHour = hour + tzOffsetDiff;
+                if (secondaryHour >= 24) secondaryHour -= 24;
+                if (secondaryHour < 0) secondaryHour += 24;
+
+                // Calculate end time for display
+                const endMinute = minute + SLOT_INTERVAL_MINUTES;
+                const endHour = hour + Math.floor(endMinute / 60);
+                const endMinuteNormalized = endMinute % 60;
+
+                return (
+                  <div
+                    key={`${hour}-${minute}`}
+                    className={cn(
+                      "grid group items-stretch transition-colors border-border/30 last:border-0",
+                      isNight ? "bg-muted/30" : "bg-card",
+                      minute === 0 ? "border-t border-border" : "border-t border-border/10",
+                      "hover:bg-muted/10"
+                    )}
+                    style={{ gridTemplateColumns: `${timeColWidth} repeat(5, 1fr)` }}
+                  >
+                    {/* Time Label - Sticky Left */}
+                    <div className={cn(
+                      "text-xs text-muted-foreground font-medium text-right pr-4 py-2 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">
+                        {minute === 0 ? (
+                          <div className="flex items-center gap-1.5 font-bold text-foreground/80">
+                            {isNight ? (
+                              <Moon className="w-3 h-3 text-slate-400/50" />
+                            ) : (
+                              <Sun className="w-3 h-3 text-amber-500/50" />
+                            )}
+                            <span>{formatTime(hour, minute)}</span>
+                          </div>
+                        ) : (
+                          <span className="text-[10px] opacity-0 group-hover:opacity-50 transition-opacity">
+                            :{minute.toString().padStart(2, '0')}
+                          </span>
+                        )}
+                      </div>
+                      {showSecondaryTimezone && (
+                        <span className="text-[10px] text-muted-foreground/60 font-mono">
+                          {formatTime(secondaryHour, minute)}
+                        </span>
+                      )}
+                    </div>
+
+                    {/* Days */}
+                    {weekDates.map(date => {
+                      const slot = getSlotForCell(date, hour, minute);
+                      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={`${date.toISOString()}-${minute}`} className="p-0.5 h-[32px] 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 ? "scale-[0.98] hover:scale-105 hover:z-10 hover:shadow-lg hover:ring-2 ring-primary/20" : ""
+                                )}>
+                                  {/* Mini Indicators for color-blind accessibility or density */}
+                                  {isFull && <Check className="w-3 h-3 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" />
+                                    {formatTime(hour, minute)} - {formatTime(endHour, endMinuteNormalized)}
+                                  </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/ParticipantSelector.tsx

@@ -94,11 +94,46 @@ export const ParticipantSelector = ({
 
   return (
     <div ref={containerRef} className="space-y-4">
-      <div className="relative">
+      <div
-        <Search className="absolute left-3 top-1/2 -translate-y-1/2 w-4 h-4 text-muted-foreground" />
+        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
           ref={inputRef}
-          placeholder="Search people..."
+          placeholder={selectedParticipants.length === 0 ? "Search people..." : "Add more..."}
           value={searchQuery}
           onChange={(e) => {
             setSearchQuery(e.target.value);
@@ -107,11 +142,25 @@ export const ParticipantSelector = ({
           }}
           onFocus={() => setIsDropdownOpen(true)}
           onKeyDown={handleKeyDown}
-          className="pl-10 h-12 bg-background border-border"
+          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">
+          <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}
@@ -159,45 +208,6 @@ export const ParticipantSelector = ({
           </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/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 * as React from "react"
-import { cva, type VariantProps } from "class-variance-authority";
+import * as SheetPrimitive from "@radix-ui/react-dialog"
-import { X } from "lucide-react";
+import { cva, type VariantProps } from "class-variance-authority"
-import * as React from "react";
+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",
+      "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,
+      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>(
+const SheetContent = React.forwardRef<
-  ({ side = "right", className, children, ...props }, ref) => (
+  React.ElementRef<typeof SheetPrimitive.Content>,
-    <SheetPortal>
+  SheetContentProps
-      <SheetOverlay />
+>(({ side = "right", className, children, ...props }, ref) => (
-      <SheetPrimitive.Content ref={ref} className={cn(sheetVariants({ side }), className)} {...props}>
+  <SheetPortal>
-        {children}
+    <SheetOverlay />
-        <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">
+    <SheetPrimitive.Content
-          <X className="h-4 w-4" />
+      ref={ref}
-          <span className="sr-only">Close</span>
+      className={cn(sheetVariants({ side }), className)}
-        </SheetPrimitive.Close>
+      {...props}
-      </SheetPrimitive.Content>
+    >
-    </SheetPortal>
+      {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" />
-SheetContent.displayName = SheetPrimitive.Content.displayName;
+        <span className="sr-only">Close</span>
+      </SheetPrimitive.Close>
+    </SheetPrimitive.Content>
+  </SheetPortal>
+))
+SheetContent.displayName = SheetPrimitive.Content.displayName
 
-const SheetHeader = ({ className, ...props }: React.HTMLAttributes<HTMLDivElement>) => (
+const SheetHeader = ({
-  <div className={cn("flex flex-col space-y-2 text-center sm:text-left", className)} {...props} />
+  className,
-);
+  ...props
-SheetHeader.displayName = "SheetHeader";
+}: 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>) => (
+const SheetFooter = ({
-  <div className={cn("flex flex-col-reverse sm:flex-row sm:justify-end sm:space-x-2", className)} {...props} />
+  className,
-);
+  ...props
-SheetFooter.displayName = "SheetFooter";
+}: 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} />
+  <SheetPrimitive.Title
-));
+    ref={ref}
-SheetTitle.displayName = SheetPrimitive.Title.displayName;
+    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} />
+  <SheetPrimitive.Description
-));
+    ref={ref}
-SheetDescription.displayName = SheetPrimitive.Description.displayName;
+    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,
+  SheetFooter,
-  SheetPortal,
   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, 
+    /* Dark mode */
-     or you can define a proper dark mode if required. 
+    .dark {
-     Keeping it simple as per previous apps. */
+      --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/pages/Index.tsx

@@ -4,6 +4,7 @@ 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';
@@ -15,6 +16,11 @@ import {
   PopoverContent,
   PopoverTrigger,
 } from '@/components/ui/popover';
+import {
+  Sheet,
+  SheetContent,
+  SheetTrigger,
+} from '@/components/ui/sheet';
 import {
   AlertDialog,
   AlertDialogAction,
@@ -61,8 +67,8 @@ interface SettingsState {
 const defaultSettings: SettingsState = {
   showPartialAvailability: false,
   displayTimezone: getUserTimezone(),
-  showSecondaryTimezone: false,
+  showSecondaryTimezone: true,
-  secondaryTimezone: 'America/Toronto', // Company timezone as default secondary
+  secondaryTimezone: 'America/Montreal', // Company timezone as default secondary
 };
 
 function apiToParticipant(p: ParticipantAPI): Participant {
@@ -89,6 +95,7 @@ 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);
@@ -314,98 +321,114 @@ const Index = ({ defaultTab = 'schedule' }: IndexProps) => {
                   >
                     <RefreshCw className={`w-5 h-5 ${isSyncing ? 'animate-spin' : ''}`} />
                   </Button>
-                  <Popover>
+                  <Sheet>
-                    <PopoverTrigger asChild>
+                    <SheetTrigger asChild>
                       <Button variant="ghost" size="icon">
                         <Settings className="w-5 h-5" />
                       </Button>
-                    </PopoverTrigger>
+                    </SheetTrigger>
-                    <PopoverContent className="w-80" align="end">
+                    <SheetContent side="right" className="w-[300px] sm:w-[350px]">
-                      <div className="space-y-4">
+                      <div className="space-y-6 py-4">
-                        <h4 className="font-medium">Settings</h4>
+                        <div className="space-y-2">
-                        <div className="flex items-center justify-between gap-4">
+                          <h4 className="font-semibold text-lg tracking-tight">Settings</h4>
-                          <Label htmlFor="partial-availability" className="text-sm cursor-pointer">
+                          <p className="text-sm text-muted-foreground">
-                            Show partial availability
+                            Configure your calendar preferences.
-                          </Label>
+                          </p>
-                          <Switch
-                            id="partial-availability"
-                            checked={settings.showPartialAvailability}
-                            onCheckedChange={(checked) =>
-                              setSettings((prev) => ({ ...prev, showPartialAvailability: checked }))
-                            }
-                          />
                         </div>
-                        <p className="text-xs text-muted-foreground">
-                          When enabled, shows time slots where only some participants are available.
-                        </p>
 
-                        <div className="border-t border-border pt-4">
+                        <div className="space-y-4">
-                          <div className="flex items-center justify-between gap-4">
+                          <div className="flex items-center justify-between gap-4 pb-4 border-b border-border">
-                            <Label htmlFor="secondary-timezone" className="text-sm cursor-pointer">
+                            <Label htmlFor="use-redesign" className="text-sm cursor-pointer font-medium text-primary">
-                              Show secondary timezone
+                              Try New Design
                             </Label>
                             <Switch
-                              id="secondary-timezone"
+                              id="use-redesign"
-                              checked={settings.showSecondaryTimezone}
+                              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, showSecondaryTimezone: checked }))
+                                setSettings((prev) => ({ ...prev, showPartialAvailability: checked }))
                               }
                             />
                           </div>
-                          {settings.showSecondaryTimezone && (
+
-                            <div className="mt-3">
+                          <div className="border-t border-border pt-4 space-y-4">
-                              <Label className="text-xs text-muted-foreground mb-2 block">
+                            <div className="flex items-center justify-between gap-4">
-                                Secondary timezone
+                              <Label htmlFor="secondary-timezone" className="text-sm cursor-pointer">
+                                Show secondary timezone
                               </Label>
-                              <TimezoneSelector
+                              <Switch
-                                value={settings.secondaryTimezone}
+                                id="secondary-timezone"
-                                onChange={(tz) => setSettings((prev) => ({ ...prev, secondaryTimezone: tz }))}
+                                checked={settings.showSecondaryTimezone}
+                                onCheckedChange={(checked) =>
+                                  setSettings((prev) => ({ ...prev, showSecondaryTimezone: checked }))
+                                }
                               />
                             </div>
-                          )}
+                            {settings.showSecondaryTimezone && (
-                          <p className="text-xs text-muted-foreground mt-2">
+                              <div className="space-y-2">
-                            Display times in two timezones side by side.
+                                <Label className="text-xs text-muted-foreground block">
-                          </p>
+                                  Secondary timezone
-                        </div>
+                                </Label>
+                                <TimezoneSelector
+                                  value={settings.secondaryTimezone}
+                                  onChange={(tz) => setSettings((prev) => ({ ...prev, secondaryTimezone: tz }))}
+                                />
+                              </div>
+                            )}
+                          </div>
 
-                        <div className="border-t border-border pt-4">
+                          <div className="border-t border-border pt-4 mt-8">
-                          <AlertDialog>
+                            <Label className="text-xs font-semibold text-muted-foreground uppercase tracking-wider mb-3 block">
-                            <AlertDialogTrigger asChild>
+                              Danger Zone
-                              <Button
+                            </Label>
-                                variant="destructive"
+                            <AlertDialog>
-                                size="sm"
+                              <AlertDialogTrigger asChild>
-                                className="w-full"
+                                <Button
-                              >
+                                  variant="outline"
-                                Clear All Bookings
+                                  size="sm"
-                              </Button>
+                                  className="text-destructive hover:text-destructive-foreground hover:bg-destructive border-destructive/30"
-                            </AlertDialogTrigger>
-                            <AlertDialogContent>
-                              <AlertDialogHeader>
-                                <AlertDialogTitle>Clear all bookings?</AlertDialogTitle>
-                                <AlertDialogDescription>
-                                  This will remove all scheduled meetings from the system.
-                                  This action cannot be undone. Calendar invites already
-                                  sent will not be affected.
-                                </AlertDialogDescription>
-                              </AlertDialogHeader>
-                              <AlertDialogFooter>
-                                <AlertDialogCancel>Cancel</AlertDialogCancel>
-                                <AlertDialogAction
-                                  onClick={handleClearBookings}
-                                  className="bg-destructive text-destructive-foreground hover:bg-destructive/90"
                                 >
-                                  Clear All
+                                  Clear All Bookings
-                                </AlertDialogAction>
+                                </Button>
-                              </AlertDialogFooter>
+                              </AlertDialogTrigger>
-                            </AlertDialogContent>
+                              <AlertDialogContent>
-                          </AlertDialog>
+                                <AlertDialogHeader>
-                          <p className="text-xs text-muted-foreground mt-2">
+                                  <AlertDialogTitle>Clear all bookings?</AlertDialogTitle>
-                            Remove all scheduled meetings from the system.
+                                  <AlertDialogDescription>
-                          </p>
+                                    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>
                       </div>
-                    </PopoverContent>
+                    </SheetContent>
-                  </Popover>
+                  </Sheet>
                 </div>
                 <h2 className="text-3xl font-bold text-foreground mb-2">
                   Schedule a Meeting
@@ -436,24 +459,39 @@ const Index = ({ defaultTab = 'schedule' }: IndexProps) => {
                     />
                   </div>
 
-                  <AvailabilityHeatmap
+                  {useRedesign ? (
-                    slots={availabilitySlots}
+                    <AvailabilityHeatmapV2
-                    selectedParticipants={selectedParticipants}
+                      slots={availabilitySlots}
-                    onSlotSelect={handleSlotSelect}
+                      selectedParticipants={selectedParticipants}
-                    showPartialAvailability={settings.showPartialAvailability}
+                      onSlotSelect={handleSlotSelect}
-                    isLoading={isLoading}
+                      showPartialAvailability={settings.showPartialAvailability}
-                    weekOffset={weekOffset}
+                      isLoading={isLoading}
-                    onWeekOffsetChange={setWeekOffset}
+                      weekOffset={weekOffset}
-                    displayTimezone={settings.displayTimezone}
+                      onWeekOffsetChange={setWeekOffset}
-                    showSecondaryTimezone={settings.showSecondaryTimezone}
+                      displayTimezone={settings.displayTimezone}
-                    secondaryTimezone={settings.secondaryTimezone}
+                      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}
@@ -466,7 +504,7 @@ const Index = ({ defaultTab = 'schedule' }: IndexProps) => {
         displayTimezone={settings.displayTimezone}
         onSuccess={loadAvailability}
       />
-    </div>
+    </div >
   );
 };
 

frontend/src/types/calendar.ts

@@ -11,6 +11,7 @@ export interface Participant {
 export interface TimeSlot {
   day: string;
   hour: number;
+  minute: number;
   start_time: string;
   availability: 'full' | 'partial' | 'none';
   availableParticipants: string[];