Merge pull request 'Improve participant selection' (#5) from more-improvements-autofocus into main

Reviewed-on: #5

backend/alembic/env.py

@@ -1,3 +1,4 @@
+import os
 from logging.config import fileConfig
 
 from alembic import context
@@ -9,6 +10,10 @@ config = context.config
 fileConfig(config.config_file_name)
 target_metadata = Base.metadata
 
+# Use SYNC_DATABASE_URL env var if set, otherwise fall back to alembic.ini
+if os.getenv("SYNC_DATABASE_URL"):
+    config.set_main_option("sqlalchemy.url", os.getenv("SYNC_DATABASE_URL"))
+
 
 def run_migrations_offline():
     url = config.get_main_option("sqlalchemy.url")

backend/alembic/versions/001_initial.py

@@ -22,7 +22,7 @@ def upgrade() -> None:
         sa.Column("id", sa.UUID(), nullable=False),
         sa.Column("name", sa.String(255), nullable=False),
         sa.Column("email", sa.String(255), nullable=False),
-        sa.Column("ics_url", sa.Text(), nullable=False),
+        sa.Column("ics_url", sa.Text(), nullable=True),
         sa.Column("created_at", sa.DateTime(), nullable=False),
         sa.Column("updated_at", sa.DateTime(), nullable=False),
         sa.PrimaryKeyConstraint("id"),

backend/alembic/versions/46a2e388b20a_add_timezone_to_participant.py

@@ -0,0 +1,29 @@
+"""add timezone to participant
+
+Revision ID: 46a2e388b20a
+Revises: 001
+Create Date: 2026-01-28 18:48:09.141869
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+revision: str = '46a2e388b20a'
+down_revision: Union[str, None] = '001'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.add_column('participants', sa.Column('timezone', sa.String(length=50), nullable=False, server_default='UTC'))
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_column('participants', 'timezone')
+    # ### end Alembic commands ###

backend/pyproject.toml

@@ -15,6 +15,9 @@ dependencies = [
     "python-dateutil>=2.9.0",
     "pydantic[email]>=2.10.0",
     "pydantic-settings>=2.6.0",
+    "apscheduler>=3.10.4",
+    "aiosmtplib>=3.0.1",
+    "zulip>=0.9.0",
 ]
 
 [project.optional-dependencies]

backend/src/app/availability_service.py

@@ -70,7 +70,7 @@ async def calculate_availability(
     participants = {p.id: p for p in participants_result.scalars().all()}
 
     days = ["Mon", "Tue", "Wed", "Thu", "Fri"]
-    hours = list(range(9, 18))
+    hours = list(range(0, 24))
     slots = []
 
     for day_offset, day_name in enumerate(days):
@@ -96,8 +96,9 @@ async def calculate_availability(
                 availability = "none"
 
             slots.append({
-                "day": day_name,
+                "day": slot_start.strftime("%Y-%m-%d"),
                 "hour": hour,
+                "start_time": slot_start,
                 "availability": availability,
                 "availableParticipants": available_participants,
             })

backend/src/app/config.py

@@ -6,6 +6,18 @@ class Settings(BaseSettings):
     sync_database_url: str = "postgresql://postgres:postgres@db:5432/availability"
     ics_refresh_interval_minutes: int = 15
 
+    # SMTP Settings
+    smtp_host: str | None = None
+    smtp_port: int = 587
+    smtp_user: str | None = None
+    smtp_password: str | None = None
+
+    # Zulip Settings
+    zulip_site: str | None = None
+    zulip_email: str | None = None
+    zulip_api_key: str | None = None
+    zulip_stream: str = "general"
+
     class Config:
         env_file = ".env"
 

backend/src/app/email_service.py

@@ -0,0 +1,82 @@
+import logging
+import uuid
+from datetime import datetime, timezone
+import aiosmtplib
+from email.message import EmailMessage
+from icalendar import Calendar, Event, vCalAddress, vText
+from app.config import settings
+
+logger = logging.getLogger(__name__)
+
+async def send_meeting_invite(
+    participants: list[dict],
+    title: str,
+    description: str,
+    start_time: datetime,
+    end_time: datetime,
+) -> bool:
+    if not settings.smtp_host or not settings.smtp_user or not settings.smtp_password:
+        logger.warning("SMTP credentials not configured. Skipping email invite.")
+        return False
+
+    # Create the ICS content
+    cal = Calendar()
+    cal.add('prodid', '-//Common Availability//m.com//')
+    cal.add('version', '2.0')
+    cal.add('method', 'REQUEST')
+
+    event = Event()
+    event.add('summary', title)
+    event.add('dtstart', start_time)
+    event.add('dtend', end_time)
+    event.add('dtstamp', datetime.now(timezone.utc))
+    event.add('description', description)
+    event.add('uid', str(uuid.uuid4()))
+    event.add('organizer', vCalAddress(f'MAILTO:{settings.smtp_user}'))
+
+    attendee_emails = []
+    for p in participants:
+        attendee = vCalAddress(f'MAILTO:{p["email"]}')
+        attendee.params['cn'] = vText(p["name"])
+        attendee.params['ROLE'] = vText('REQ-PARTICIPANT')
+        event.add('attendee', attendee, encode=0)
+        attendee_emails.append(p["email"])
+
+    cal.add_component(event)
+    ics_data = cal.to_ical()
+
+    # Create Email
+    msg = EmailMessage()
+    msg["Subject"] = f"Invitation: {title}"
+    msg["From"] = settings.smtp_user
+    msg["To"] = ", ".join(attendee_emails)
+    msg.set_content(
+        f"You have been invited to: {title}\n"
+        f"When: {start_time.strftime('%Y-%m-%d %H:%M %Z')}\n\n"
+        f"{description}"
+    )
+
+    # Attach ICS
+    msg.add_attachment(
+        ics_data,
+        maintype="text",
+        subtype="calendar",
+        filename="invite.ics",
+        params={"method": "REQUEST"}
+    )
+
+    # Send
+    try:
+        await aiosmtplib.send(
+            msg,
+            hostname=settings.smtp_host,
+            port=settings.smtp_port,
+            username=settings.smtp_user,
+            password=settings.smtp_password,
+            start_tls=True
+        )
+        logger.info(f"Sent meeting invites to {len(attendee_emails)} participants")
+        return True
+    except Exception as e:
+        logger.error(f"Failed to send email invite: {e}")
+        return False

backend/src/app/main.py

@@ -1,3 +1,4 @@
+import asyncio
 import logging
 from uuid import UUID
 
@@ -14,14 +15,27 @@ from app.schemas import (
     AvailabilityRequest,
     AvailabilityResponse,
     ParticipantCreate,
+    ParticipantUpdate,
     ParticipantResponse,
     SyncResponse,
+    ScheduleRequest,
 )
+from app.scheduler import start_scheduler, stop_scheduler
+from app.email_service import send_meeting_invite
+from app.zulip_service import send_zulip_notification
+from contextlib import asynccontextmanager
+from datetime import datetime, timezone, timedelta
 
 logging.basicConfig(level=logging.INFO)
 logger = logging.getLogger(__name__)
 
-app = FastAPI(title="Common Availability API")
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    start_scheduler()
+    yield
+    stop_scheduler()
+
+app = FastAPI(title="Common Availability API", lifespan=lifespan)
 
 app.add_middleware(
     CORSMiddleware,
@@ -50,6 +64,7 @@ async def create_participant(
     participant = Participant(
         name=data.name,
         email=data.email,
+        timezone=data.timezone,
         ics_url=data.ics_url,
     )
     db.add(participant)
@@ -57,7 +72,8 @@ async def create_participant(
     await db.refresh(participant)
 
     try:
-        await sync_participant_calendar(db, participant)
+        if participant.ics_url:
+            await sync_participant_calendar(db, participant)
     except Exception as e:
         logger.warning(f"Initial sync failed for {participant.email}: {e}")
 
@@ -81,6 +97,35 @@ async def get_participant(participant_id: UUID, db: AsyncSession = Depends(get_d
     return participant
 
 
+@app.patch("/api/participants/{participant_id}", response_model=ParticipantResponse)
+async def update_participant(
+    participant_id: UUID, data: ParticipantUpdate, db: AsyncSession = Depends(get_db)
+):
+    result = await db.execute(
+        select(Participant).where(Participant.id == participant_id)
+    )
+    participant = result.scalar_one_or_none()
+    if not participant:
+        raise HTTPException(status_code=404, detail="Participant not found")
+
+    if data.timezone is not None:
+        participant.timezone = data.timezone
+    if data.ics_url is not None:
+        participant.ics_url = data.ics_url if data.ics_url else None
+
+    await db.commit()
+    await db.refresh(participant)
+
+    # Re-sync calendar if ICS URL was updated
+    if data.ics_url is not None and participant.ics_url:
+        try:
+            await sync_participant_calendar(db, participant)
+        except Exception as e:
+            logger.warning(f"Calendar sync failed for {participant.email}: {e}")
+
+    return participant
+
+
 @app.delete("/api/participants/{participant_id}")
 async def delete_participant(participant_id: UUID, db: AsyncSession = Depends(get_db)):
     result = await db.execute(
@@ -99,7 +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}
 
 
@@ -121,7 +167,54 @@ async def sync_participant(participant_id: UUID, db: AsyncSession = Depends(get_
         raise HTTPException(status_code=404, detail="Participant not found")
 
     try:
-        count = await sync_participant_calendar(db, participant)
+        if participant.ics_url:
-        return {"status": "success", "blocks_synced": count}
+            count = await sync_participant_calendar(db, participant)
+            return {"status": "success", "blocks_synced": count}
+        return {"status": "skipped", "message": "No ICS URL provided"}
     except Exception as e:
         raise HTTPException(status_code=500, detail=str(e))
+
+
+@app.post("/api/schedule")
+async def schedule_meeting(
+    data: ScheduleRequest, db: AsyncSession = Depends(get_db)
+):
+    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, 
+            detail="Meetings must be scheduled at least 2 hours in advance."
+        )
+
+    result = await db.execute(
+        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")
+
+    participant_dicts = [
+        {"name": p.name, "email": p.email} for p in participants
+    ]
+
+    email_success = await send_meeting_invite(
+        participant_dicts,
+        data.title,
+        data.description,
+        data.start_time,
+        data.end_time
+    )
+
+    zulip_success = await asyncio.to_thread(
+        send_zulip_notification,
+        data.title,
+        data.start_time,
+        participant_dicts
+    )
+
+    return {
+        "status": "success",
+        "email_sent": email_success,
+        "zulip_sent": zulip_success
+    }

backend/src/app/models.py

@@ -18,7 +18,8 @@ class Participant(Base):
     )
     name: Mapped[str] = mapped_column(String(255), nullable=False)
     email: Mapped[str] = mapped_column(String(255), nullable=False, unique=True)
-    ics_url: Mapped[str] = mapped_column(Text, nullable=False)
+    timezone: Mapped[str] = mapped_column(String(50), nullable=False, default="America/Toronto")
+    ics_url: Mapped[str | None] = mapped_column(Text, nullable=True)
     created_at: Mapped[datetime] = mapped_column(
         DateTime, default=datetime.utcnow, nullable=False
     )

backend/src/app/scheduler.py

@@ -0,0 +1,39 @@
+import logging
+from apscheduler.schedulers.asyncio import AsyncIOScheduler
+from apscheduler.triggers.interval import IntervalTrigger
+from sqlalchemy import select
+from app.database import async_session_maker
+from app.models import Participant
+from app.ics_service import sync_participant_calendar
+from app.config import settings
+
+logger = logging.getLogger(__name__)
+
+scheduler = AsyncIOScheduler()
+
+async def run_sync_job():
+    logger.info("Starting background calendar sync...")
+    async with async_session_maker() as db:
+        result = await db.execute(select(Participant).where(Participant.ics_url.is_not(None)))
+        participants = result.scalars().all()
+        
+        for participant in participants:
+            try:
+                await sync_participant_calendar(db, participant)
+            except Exception as e:
+                logger.error(f"Background sync failed for {participant.email}: {e}")
+    logger.info("Background calendar sync completed.")
+
+def start_scheduler():
+    scheduler.add_job(
+        run_sync_job,
+        IntervalTrigger(minutes=settings.ics_refresh_interval_minutes),
+        id="calendar_sync",
+        replace_existing=True
+    )
+    scheduler.start()
+    logger.info("Scheduler started.")
+
+def stop_scheduler():
+    scheduler.shutdown()
+    logger.info("Scheduler stopped.")

backend/src/app/schemas.py

@@ -7,14 +7,21 @@ from pydantic import BaseModel, EmailStr
 class ParticipantCreate(BaseModel):
     name: str
     email: EmailStr
-    ics_url: str
+    timezone: str = "America/Toronto"
+    ics_url: str | None = None
+
+
+class ParticipantUpdate(BaseModel):
+    timezone: str | None = None
+    ics_url: str | None = None
 
 
 class ParticipantResponse(BaseModel):
     id: UUID
     name: str
     email: str
-    ics_url: str
+    timezone: str
+    ics_url: str | None
     created_at: datetime
     updated_at: datetime
 
@@ -25,12 +32,14 @@ class ParticipantResponse(BaseModel):
 class TimeSlot(BaseModel):
     day: str
     hour: int
+    start_time: datetime
     availability: str
     availableParticipants: list[str]
 
 
 class AvailabilityRequest(BaseModel):
     participant_ids: list[UUID]
+    week_offset: int = 0
 
 
 class AvailabilityResponse(BaseModel):
@@ -39,3 +48,11 @@ class AvailabilityResponse(BaseModel):
 
 class SyncResponse(BaseModel):
     results: dict[str, dict]
+
+
+class ScheduleRequest(BaseModel):
+    participant_ids: list[UUID]
+    title: str
+    description: str
+    start_time: datetime
+    end_time: datetime

backend/src/app/zulip_service.py

@@ -0,0 +1,83 @@
+import logging
+import zulip
+from app.config import settings
+from datetime import datetime
+
+logger = logging.getLogger(__name__)
+
+
+def get_zulip_usernames_by_email(client: zulip.Client) -> dict[str, str]:
+    """Fetch all Zulip users and return a mapping of email -> full_name for mentions."""
+    try:
+        result = client.get_users()
+        if result.get("result") == "success":
+            users_map = {
+                user["email"].lower(): user["full_name"]
+                for user in result.get("members", [])
+                if not user.get("is_bot", False)
+            }
+            return users_map
+    except Exception as e:
+        logger.warning(f"Failed to fetch Zulip users: {e}")
+    return {}
+
+
+def format_participant_mentions(
+    participants: list[dict],
+    zulip_users: dict[str, str],
+) -> str:
+    """Format participants as Zulip mentions where possible, plain names otherwise."""
+    formatted = []
+    for p in participants:
+        email = p["email"].lower()
+        if email in zulip_users:
+            formatted.append(f'@**{zulip_users[email]}**')
+        else:
+            formatted.append(p["name"])
+    return ", ".join(formatted)
+
+
+def send_zulip_notification(
+    title: str,
+    start_time: datetime,
+    participants: list[dict],
+) -> bool:
+    if not settings.zulip_site or not settings.zulip_api_key or not settings.zulip_email:
+        return False
+
+    try:
+        client = zulip.Client(
+            email=settings.zulip_email,
+            api_key=settings.zulip_api_key,
+            site=settings.zulip_site
+        )
+
+        zulip_users = get_zulip_usernames_by_email(client)
+        people = format_participant_mentions(participants, zulip_users)
+
+        zulip_time = f"<time:{start_time.isoformat()}>"
+
+        content = (
+            f"📅 **Meeting Scheduled**\n"
+            f"**What:** {title}\n"
+            f"**When:** {zulip_time}\n"
+            f"**Who:** {people}"
+        )
+
+        request = {
+            "type": "stream",
+            "to": settings.zulip_stream,
+            "topic": "Meeting Announcements",
+            "content": content
+        }
+
+        result = client.send_message(request)
+        if result.get("result") == "success":
+            return True
+        else:
+            logger.error(f"Zulip API error: {result.get('msg')}")
+            return False
+
+    except Exception as e:
+        logger.error(f"Failed to send Zulip notification: {e}")
+        return False

docker-compose.dev.yml

@@ -0,0 +1,50 @@
+services:
+  db:
+    image: postgres:16-alpine
+    environment:
+      POSTGRES_USER: postgres
+      POSTGRES_PASSWORD: postgres
+      POSTGRES_DB: availability
+    volumes:
+      - postgres_data:/var/lib/postgresql/data
+    ports:
+      - "5433:5432"
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U postgres"]
+      interval: 5s
+      timeout: 5s
+      retries: 5
+
+  backend:
+    build:
+      context: ./backend
+      dockerfile: Dockerfile
+    environment:
+      DATABASE_URL: postgresql+asyncpg://postgres:postgres@db:5432/availability
+      SYNC_DATABASE_URL: postgresql://postgres:postgres@db:5432/availability
+    env_file:
+      - .env
+    ports:
+      - "8001:8000"
+    depends_on:
+      db:
+        condition: service_healthy
+    volumes:
+      - ./backend/src:/app/src
+      - ./backend/alembic:/app/alembic
+
+  frontend:
+    build:
+      context: ./frontend
+      dockerfile: Dockerfile
+    ports:
+      - "5174:8080"
+    environment:
+      VITE_API_URL: http://localhost:8001
+    depends_on:
+      - backend
+    volumes:
+      - ./frontend/src:/app/src
+
+volumes:
+  postgres_data:

docker-compose.yml

@@ -2,47 +2,53 @@ services:
   db:
     image: postgres:16-alpine
     environment:
-      POSTGRES_USER: postgres
+      POSTGRES_USER: ${POSTGRES_USER:-postgres}
-      POSTGRES_PASSWORD: postgres
+      POSTGRES_PASSWORD: ${POSTGRES_PASSWORD:?POSTGRES_PASSWORD required}
-      POSTGRES_DB: availability
+      POSTGRES_DB: ${POSTGRES_DB:-availability}
     volumes:
       - postgres_data:/var/lib/postgresql/data
-    ports:
-      - "5432:5432"
     healthcheck:
       test: ["CMD-SHELL", "pg_isready -U postgres"]
       interval: 5s
       timeout: 5s
       retries: 5
+    restart: unless-stopped
 
   backend:
     build:
       context: ./backend
       dockerfile: Dockerfile
     environment:
-      DATABASE_URL: postgresql+asyncpg://postgres:postgres@db:5432/availability
+      DATABASE_URL: postgresql+asyncpg://${POSTGRES_USER:-postgres}:${POSTGRES_PASSWORD}@db:5432/${POSTGRES_DB:-availability}
-      SYNC_DATABASE_URL: postgresql://postgres:postgres@db:5432/availability
+      SYNC_DATABASE_URL: postgresql://${POSTGRES_USER:-postgres}:${POSTGRES_PASSWORD}@db:5432/${POSTGRES_DB:-availability}
-    ports:
+      SMTP_HOST: ${SMTP_HOST:-}
-      - "8000:8000"
+      SMTP_PORT: ${SMTP_PORT:-587}
+      SMTP_USER: ${SMTP_USER:-}
+      SMTP_PASSWORD: ${SMTP_PASSWORD:-}
+      ZULIP_SITE: ${ZULIP_SITE:-}
+      ZULIP_EMAIL: ${ZULIP_EMAIL:-}
+      ZULIP_API_KEY: ${ZULIP_API_KEY:-}
+      ZULIP_STREAM: ${ZULIP_STREAM:-general}
     depends_on:
       db:
         condition: service_healthy
-    volumes:
+    labels:
-      - ./backend/src:/app/src
+      - traefik.http.middlewares.authentik-auth@file
-      - ./backend/alembic:/app/alembic
+    restart: unless-stopped
 
   frontend:
     build:
       context: ./frontend
-      dockerfile: Dockerfile
+      dockerfile: Dockerfile.prod
-    ports:
+      args:
-      - "5173:8080"
+        VITE_API_URL: ${VITE_API_URL:-}
-    environment:
-      VITE_API_URL: http://localhost:8000
     depends_on:
       - backend
-    volumes:
+    labels:
-      - ./frontend/src:/app/src
+      - traefik.http.middlewares.authentik-auth@file
+    restart: unless-stopped
+    expose:
+      - '80'
 
 volumes:
   postgres_data:

frontend/Dockerfile.prod

@@ -0,0 +1,28 @@
+# Build stage
+FROM node:20-alpine AS builder
+
+WORKDIR /app
+
+COPY package*.json ./
+RUN npm ci
+
+COPY . .
+
+# VITE_API_URL must be set at build time
+ARG VITE_API_URL
+ENV VITE_API_URL=${VITE_API_URL}
+
+RUN npm run build
+
+# Production stage
+FROM nginx:alpine
+
+# Copy built assets
+COPY --from=builder /app/dist /usr/share/nginx/html
+
+# Copy nginx config
+COPY nginx.conf /etc/nginx/conf.d/default.conf
+
+EXPOSE 80
+
+CMD ["nginx", "-g", "daemon off;"]

frontend/nginx.conf

@@ -0,0 +1,19 @@
+server {
+    listen 80;
+    server_name _;
+    root /usr/share/nginx/html;
+    index index.html;
+
+    location / {
+        try_files $uri $uri/ /index.html;
+    }
+
+    location /assets/ {
+        expires 1y;
+        add_header Cache-Control "public, immutable";
+    }
+
+    gzip on;
+    gzip_types text/css application/javascript application/json image/svg+xml;
+    gzip_comp_level 6;
+}

frontend/package-lock.json

@@ -2859,7 +2859,6 @@
       "integrity": "sha512-bJFoMATwIGaxxx8VJPeM8TonI8t579oRvgAuT8zFugJsJZgzqv0Fu8Mhp68iecjzG7cnN3mO2dJQ5uUM2EFrgQ==",
       "dev": true,
       "license": "MIT",
-      "peer": true,
       "dependencies": {
         "undici-types": "~6.21.0"
       }
@@ -2877,7 +2876,6 @@
       "integrity": "sha512-/LDXMQh55EzZQ0uVAZmKKhfENivEvWz6E+EYzh+/MCjMhNsotd+ZHhBGIjFDTi6+fz0OhQQQLbTgdQIxxCsC0w==",
       "devOptional": true,
       "license": "MIT",
-      "peer": true,
       "dependencies": {
         "@types/prop-types": "*",
         "csstype": "^3.0.2"
@@ -2889,7 +2887,6 @@
       "integrity": "sha512-MEe3UeoENYVFXzoXEWsvcpg6ZvlrFNlOQ7EOsvhI3CfAXwzPfO8Qwuxd40nepsYKqyyVQnTdEfv68q91yLcKrQ==",
       "devOptional": true,
       "license": "MIT",
-      "peer": true,
       "peerDependencies": {
         "@types/react": "^18.0.0"
       }
@@ -2940,7 +2937,6 @@
       "integrity": "sha512-Zhy8HCvBUEfBECzIl1PKqF4p11+d0aUJS1GeUiuqK9WmOug8YCmC4h4bjyBvMyAMI9sbRczmrYL5lKg/YMbrcQ==",
       "dev": true,
       "license": "MIT",
-      "peer": true,
       "dependencies": {
         "@typescript-eslint/scope-manager": "8.38.0",
         "@typescript-eslint/types": "8.38.0",
@@ -3173,7 +3169,6 @@
       "integrity": "sha512-NZyJarBfL7nWwIq+FDL6Zp/yHEhePMNnnJ0y3qfieCrmNvYct8uvtiV41UvlSe6apAfk0fY1FbWx+NwfmpvtTg==",
       "dev": true,
       "license": "MIT",
-      "peer": true,
       "bin": {
         "acorn": "bin/acorn"
       },
@@ -3378,7 +3373,6 @@
         }
       ],
       "license": "MIT",
-      "peer": true,
       "dependencies": {
         "caniuse-lite": "^1.0.30001726",
         "electron-to-chromium": "^1.5.173",
@@ -3712,7 +3706,6 @@
       "resolved": "https://registry.npmjs.org/date-fns/-/date-fns-3.6.0.tgz",
       "integrity": "sha512-fRHTG8g/Gif+kSh50gaGEdToemgfj74aRX3swtiouboip5JDLAyDE9F11nHMIcvOaXeOC6D7SpNhi7uFyB7Uww==",
       "license": "MIT",
-      "peer": true,
       "funding": {
         "type": "github",
         "url": "https://github.com/sponsors/kossnocorp"
@@ -3794,8 +3787,7 @@
       "version": "8.6.0",
       "resolved": "https://registry.npmjs.org/embla-carousel/-/embla-carousel-8.6.0.tgz",
       "integrity": "sha512-SjWyZBHJPbqxHOzckOfo8lHisEaJWmwd23XppYFYVh10bU66/Pn5tkVkbkCMZVdbUE5eTCI2nD8OyIP4Z+uwkA==",
-      "license": "MIT",
+      "license": "MIT"
-      "peer": true
     },
     "node_modules/embla-carousel-react": {
       "version": "8.6.0",
@@ -3893,7 +3885,6 @@
       "integrity": "sha512-LSehfdpgMeWcTZkWZVIJl+tkZ2nuSkyyB9C27MZqFWXuph7DvaowgcTvKqxvpLW1JZIk8PN7hFY3Rj9LQ7m7lg==",
       "dev": true,
       "license": "MIT",
-      "peer": true,
       "dependencies": {
         "@eslint-community/eslint-utils": "^4.2.0",
         "@eslint-community/regexpp": "^4.12.1",
@@ -5415,7 +5406,6 @@
         }
       ],
       "license": "MIT",
-      "peer": true,
       "dependencies": {
         "nanoid": "^3.3.11",
         "picocolors": "^1.1.1",
@@ -5602,7 +5592,6 @@
       "resolved": "https://registry.npmjs.org/react/-/react-18.3.1.tgz",
       "integrity": "sha512-wS+hAgJShR0KhEvPJArfuPVN1+Hz1t0Y6n5jLrGQbkb4urgPE/0Rve+1kMB1v/oWgHgm4WIcV+i7F2pTVj+2iQ==",
       "license": "MIT",
-      "peer": true,
       "dependencies": {
         "loose-envify": "^1.1.0"
       },
@@ -5629,7 +5618,6 @@
       "resolved": "https://registry.npmjs.org/react-dom/-/react-dom-18.3.1.tgz",
       "integrity": "sha512-5m4nQKp+rZRb09LNH59GM4BxTh9251/ylbKIbpe7TpGxfJ+9kv6BLkLBXIjjspbgbnIBNqlI23tRnTWT0snUIw==",
       "license": "MIT",
-      "peer": true,
       "dependencies": {
         "loose-envify": "^1.1.0",
         "scheduler": "^0.23.2"
@@ -5643,7 +5631,6 @@
       "resolved": "https://registry.npmjs.org/react-hook-form/-/react-hook-form-7.61.1.tgz",
       "integrity": "sha512-2vbXUFDYgqEgM2RcXcAT2PwDW/80QARi+PKmHy5q2KhuKvOlG8iIYgf7eIlIANR5trW9fJbP4r5aub3a4egsew==",
       "license": "MIT",
-      "peer": true,
       "engines": {
         "node": ">=18.0.0"
       },
@@ -6197,7 +6184,6 @@
       "resolved": "https://registry.npmjs.org/tailwindcss/-/tailwindcss-3.4.17.tgz",
       "integrity": "sha512-w33E2aCvSDP0tW9RZuNXadXlkHXqFzSkQew/aIa2i/Sj8fThxwovwlXHSPXTbAHwEIhBFXAedUhP2tueAKP8Og==",
       "license": "MIT",
-      "peer": true,
       "dependencies": {
         "@alloc/quick-lru": "^5.2.0",
         "arg": "^5.0.2",
@@ -6322,7 +6308,6 @@
       "integrity": "sha512-p1diW6TqL9L07nNxvRMM7hMMw4c5XOo/1ibL4aAIGmSAt9slTE1Xgw5KWuof2uTOvCg9BY7ZRi+GaF+7sfgPeQ==",
       "dev": true,
       "license": "Apache-2.0",
-      "peer": true,
       "bin": {
         "tsc": "bin/tsc",
         "tsserver": "bin/tsserver"
@@ -6502,7 +6487,6 @@
       "integrity": "sha512-qO3aKv3HoQC8QKiNSTuUM1l9o/XX3+c+VTgLHbJWHZGeTPVAg2XwazI9UWzoxjIJCGCV2zU60uqMzjeLZuULqA==",
       "dev": true,
       "license": "MIT",
-      "peer": true,
       "dependencies": {
         "esbuild": "^0.21.3",
         "postcss": "^8.4.43",

frontend/src/App.tsx

@@ -16,6 +16,8 @@ const App = () => (
       <BrowserRouter>
         <Routes>
           <Route path="/" element={<Index />} />
+          <Route path="/participants" element={<Index defaultTab="participants" />} />
+          <Route path="/schedule" element={<Index defaultTab="schedule" />} />
           {/* ADD ALL CUSTOM ROUTES ABOVE THE CATCH-ALL "*" ROUTE */}
           <Route path="*" element={<NotFound />} />
         </Routes>

frontend/src/api/client.ts

@@ -1,10 +1,12 @@
-const API_URL = import.meta.env.VITE_API_URL || 'http://localhost:8000';
+// Use VITE_API_URL if set at build time, otherwise derive from current origin
+const API_URL = import.meta.env.VITE_API_URL || `${window.location.origin}/api`;
 
 export interface ParticipantAPI {
   id: string;
   name: string;
   email: string;
-  ics_url: string;
+  timezone: string;
+  ics_url: string | null;
   created_at: string;
   updated_at: string;
 }
@@ -12,6 +14,7 @@ export interface ParticipantAPI {
 export interface TimeSlotAPI {
   day: string;
   hour: number;
+  start_time: string;
   availability: 'full' | 'partial' | 'none';
   availableParticipants: string[];
 }
@@ -19,7 +22,13 @@ export interface TimeSlotAPI {
 export interface CreateParticipantRequest {
   name: string;
   email: string;
-  ics_url: string;
+  timezone: string;
+  ics_url?: string;
+}
+
+export interface UpdateParticipantRequest {
+  timezone?: string;
+  ics_url?: string;
 }
 
 async function handleResponse<T>(response: Response): Promise<T> {
@@ -44,6 +53,15 @@ export async function createParticipant(data: CreateParticipantRequest): Promise
   return handleResponse<ParticipantAPI>(response);
 }
 
+export async function updateParticipant(id: string, data: UpdateParticipantRequest): Promise<ParticipantAPI> {
+  const response = await fetch(`${API_URL}/api/participants/${id}`, {
+    method: 'PATCH',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify(data),
+  });
+  return handleResponse<ParticipantAPI>(response);
+}
+
 export async function deleteParticipant(id: string): Promise<void> {
   const response = await fetch(`${API_URL}/api/participants/${id}`, {
     method: 'DELETE',
@@ -53,11 +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(`${API_URL}/api/availability`, {
     method: 'POST',
     headers: { 'Content-Type': 'application/json' },
-    body: JSON.stringify({ participant_ids: participantIds }),
+    body: JSON.stringify({ participant_ids: participantIds, week_offset: weekOffset }),
   });
   const data = await handleResponse<{ slots: TimeSlotAPI[] }>(response);
   return data.slots;
@@ -76,3 +94,24 @@ export async function syncParticipant(id: string): Promise<void> {
     throw new Error('Failed to sync participant calendar');
   }
 }
+
+export async function scheduleMeeting(
+  participantIds: string[],
+  title: string,
+  description: string,
+  startTime: string,
+  endTime: string,
+): Promise<{ email_sent: boolean; zulip_sent: boolean }> {
+  const response = await fetch(`${API_URL}/api/schedule`, {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify({
+      participant_ids: participantIds,
+      title,
+      description,
+      start_time: startTime,
+      end_time: endTime,
+    }),
+  });
+  return handleResponse(response);
+}

frontend/src/components/AvailabilityHeatmap.tsx

@@ -6,17 +6,86 @@ import {
   PopoverTrigger,
 } from '@/components/ui/popover';
 import { Button } from '@/components/ui/button';
-import { Check, X, Loader2 } from 'lucide-react';
+import { useState } from 'react';
+import { Check, X, Loader2, ChevronLeft, ChevronRight, ChevronsRight } from 'lucide-react';
 
-const days = ['Mon', 'Tue', 'Wed', 'Thu', 'Fri'];
+const TIMEZONE = 'America/Toronto';
+
+const dayNames = ['Mon', 'Tue', 'Wed', 'Thu', 'Fri'];
 const hours = [9, 10, 11, 12, 13, 14, 15, 16, 17];
 
+// 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', {
+    timeZone: timezone,
+    year: 'numeric',
+    month: '2-digit',
+    day: '2-digit',
+  });
+
+  // Parse today's date in the target timezone
+  const todayStr = formatter.format(now);
+  const [year, month, day] = todayStr.split('-').map(Number);
+
+  // Calculate Monday of this week
+  const todayDate = new Date(year, month - 1, day);
+  const dayOfWeek = todayDate.getDay();
+  const daysToMonday = dayOfWeek === 0 ? -6 : 1 - dayOfWeek;
+
+  const mondayDate = new Date(year, month - 1, day + daysToMonday + weekOffset * 7);
+
+  return dayNames.map((_, i) => {
+    const d = new Date(mondayDate);
+    d.setDate(mondayDate.getDate() + i);
+    const y = d.getFullYear();
+    const m = String(d.getMonth() + 1).padStart(2, '0');
+    const dd = String(d.getDate()).padStart(2, '0');
+    return `${y}-${m}-${dd}`;
+  });
+};
+
+// Convert a date string and hour in a timezone to a UTC Date
+const toUTCDate = (dateStr: string, hour: number, timezone: string): Date => {
+  // Create a date string that represents the given hour in the given timezone
+  // Then parse it to get the UTC equivalent
+  const localDateStr = `${dateStr}T${String(hour).padStart(2, '0')}:00:00`;
+
+  // Use a trick: format in UTC then in target TZ to find the offset
+  const testDate = new Date(localDateStr + 'Z'); // Treat as UTC first
+
+  // Get what hour this would be in the target timezone
+  const tzHour = parseInt(
+    new Intl.DateTimeFormat('en-US', {
+      timeZone: timezone,
+      hour: 'numeric',
+      hour12: false,
+    }).format(testDate)
+  );
+
+  // Calculate offset in hours
+  const offset = tzHour - testDate.getUTCHours();
+
+  // Adjust: if we want `hour` in timezone, subtract the offset to get UTC
+  const utcDate = new Date(localDateStr + 'Z');
+  utcDate.setUTCHours(utcDate.getUTCHours() - offset);
+
+  return utcDate;
+};
+
+const MIN_WEEK_OFFSET = 0;
+const DEFAULT_MAX_WEEK_OFFSET = 1;
+const EXPANDED_MAX_WEEK_OFFSET = 4;
+
 interface AvailabilityHeatmapProps {
   slots: TimeSlot[];
   selectedParticipants: Participant[];
   onSlotSelect: (slot: TimeSlot) => void;
   showPartialAvailability?: boolean;
   isLoading?: boolean;
+  weekOffset?: number;
+  onWeekOffsetChange?: (offset: number) => void;
 }
 
 export const AvailabilityHeatmap = ({
@@ -25,9 +94,23 @@ export const AvailabilityHeatmap = ({
   onSlotSelect,
   showPartialAvailability = false,
   isLoading = false,
+  weekOffset = 0,
+  onWeekOffsetChange,
 }: AvailabilityHeatmapProps) => {
-  const getSlot = (day: string, hour: number) => {
+  const [expanded, setExpanded] = useState(false);
-    return slots.find((s) => s.day === day && s.hour === hour);
+  const maxWeekOffset = expanded ? EXPANDED_MAX_WEEK_OFFSET : DEFAULT_MAX_WEEK_OFFSET;
+  const weekDates = getWeekDates(TIMEZONE, weekOffset);
+
+  // 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);
+
+    return slots.find((s) => {
+      const slotDate = new Date(s.start_time);
+      // Compare UTC timestamps (with some tolerance for rounding)
+      return Math.abs(slotDate.getTime() - targetUTC.getTime()) < 60000; // 1 minute tolerance
+    });
   };
 
   const getEffectiveAvailability = (slot: TimeSlot) => {
@@ -41,17 +124,36 @@ export const AvailabilityHeatmap = ({
     return `${hour.toString().padStart(2, '0')}:00`;
   };
 
-  const getWeekDateRange = () => {
+  const isSlotTooSoon = (dateStr: string, hour: number) => {
+    // Convert to UTC and compare with current time
+    const slotTimeUTC = toUTCDate(dateStr, hour, TIMEZONE);
     const now = new Date();
-    const monday = new Date(now);
+    const twoHoursFromNow = new Date(now.getTime() + 2 * 60 * 60 * 1000);
-    monday.setDate(now.getDate() - now.getDay() + 1);
+    return slotTimeUTC < twoHoursFromNow;
-    const friday = new Date(monday);
+  };
-    friday.setDate(monday.getDate() + 4);
 
-    const format = (d: Date) => d.toLocaleDateString('en-US', { month: 'short', day: 'numeric' });
+  const getWeekDateRange = () => {
+    if (weekDates.length < 5) return '';
+    const monday = new Date(weekDates[0] + 'T12:00:00Z');
+    const friday = new Date(weekDates[4] + 'T12:00:00Z');
+
+    const format = (d: Date) =>
+      d.toLocaleDateString('en-US', { month: 'short', day: 'numeric', timeZone: 'UTC' });
     return `${format(monday)} – ${format(friday)}`;
   };
 
+  // Format hour for display in popover (in the display timezone)
+  const formatDisplayTime = (hour: number) => {
+    // Create a date at that hour
+    const date = new Date();
+    date.setHours(hour, 0, 0, 0);
+    return new Intl.DateTimeFormat('en-US', {
+      hour: 'numeric',
+      minute: '2-digit',
+      hour12: true,
+    }).format(date);
+  };
+
   if (selectedParticipants.length === 0) {
     return (
       <div className="bg-card rounded-xl shadow-card p-8 text-center animate-fade-in">
@@ -74,25 +176,84 @@ export const AvailabilityHeatmap = ({
 
   return (
     <div className="bg-card rounded-xl shadow-card p-6 animate-slide-up">
-      <div className="mb-6">
+      <div className="mb-6 flex justify-between items-start">
-        <h3 className="text-lg font-semibold text-foreground">
+        <div>
-          Common Availability — Week of {getWeekDateRange()}
+          <div className="flex items-center gap-2">
-        </h3>
+            <h3 className="text-lg font-semibold text-foreground">
-        <p className="text-sm text-muted-foreground mt-1">
+              Common Availability — Week of {getWeekDateRange()}
-          {selectedParticipants.length} participant{selectedParticipants.length > 1 ? 's' : ''}: {selectedParticipants.map(p => p.name.split(' ')[0]).join(', ')}
+            </h3>
-        </p>
+          </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(', ')}
+          </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>
-            {days.map((day) => (
+            {dayNames.map((dayName, i) => (
               <div
-                key={day}
+                key={dayName}
                 className="text-center text-sm font-medium text-muted-foreground py-2"
               >
-                {day}
+                <div>{dayName}</div>
+                <div className="text-xs opacity-70">
+                  {weekDates[i]?.slice(5).replace('-', '/')}
+                </div>
               </div>
             ))}
           </div>
@@ -103,18 +264,22 @@ export const AvailabilityHeatmap = ({
                 <div className="text-xs text-muted-foreground flex items-center justify-end pr-3">
                   {formatHour(hour)}
                 </div>
-                {days.map((day) => {
+                {weekDates.map((dateStr, dayIndex) => {
-                  const slot = getSlot(day, hour);
+                  const slot = getSlot(dateStr, hour);
-                  if (!slot) return <div key={`${day}-${hour}`} className="h-12 bg-muted rounded" />;
+                  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);
 
                   return (
-                    <Popover key={`${day}-${hour}`}>
+                    <Popover key={`${dateStr}-${hour}`}>
                       <PopoverTrigger asChild>
                         <button
                           className={cn(
-                            "h-12 rounded-md transition-all duration-200 hover:scale-105 hover:shadow-md focus:outline-none focus:ring-2 focus:ring-ring focus:ring-offset-2",
+                            "h-12 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",
                             effectiveAvailability === 'full' && "bg-availability-full hover:bg-availability-full/90",
                             effectiveAvailability === 'partial' && "bg-availability-partial hover:bg-availability-partial/90",
                             effectiveAvailability === 'none' && "bg-availability-none hover:bg-availability-none/90"
@@ -124,11 +289,17 @@ export const AvailabilityHeatmap = ({
                       <PopoverContent className="w-64 p-4 animate-scale-in" align="center">
                         <div className="space-y-3">
                           <div className="font-semibold text-foreground">
-                            {day} {formatHour(hour)}–{formatHour(hour + 1)}
+                            {dayName} {formatDisplayTime(hour)}–{formatDisplayTime(hour + 1)}
                           </div>
+                          {tooSoon && (
+                            <div className="text-sm text-muted-foreground italic">
+                              This time slot has passed or is too soon to schedule
+                            </div>
+                          )}
                           <div className="space-y-2">
                             {selectedParticipants.map((participant) => {
                               const isAvailable = slot.availableParticipants.includes(participant.name);
+
                               return (
                                 <div
                                   key={participant.id}
@@ -142,13 +313,13 @@ export const AvailabilityHeatmap = ({
                                   <span className={cn(
                                     isAvailable ? "text-foreground" : "text-muted-foreground"
                                   )}>
-                                    {participant.name.split(' ')[0]} {isAvailable ? 'free' : 'busy'}
+                                    {participant.name.split(' ')[0]}
                                   </span>
                                 </div>
                               );
                             })}
                           </div>
-                          {effectiveAvailability !== 'none' && (
+                          {effectiveAvailability !== 'none' && !tooSoon && (
                             <Button
                               variant="schedule"
                               className="w-full mt-2"

frontend/src/components/Header.tsx

@@ -1,4 +1,5 @@
 import { Calendar } from 'lucide-react';
+import { getAvatarColor } from '@/lib/utils';
 
 export const Header = () => {
   return (
@@ -14,7 +15,10 @@ export const Header = () => {
           </div>
         </div>
         <div className="flex items-center gap-2">
-          <div className="w-8 h-8 rounded-full bg-primary/10 flex items-center justify-center text-sm font-medium text-primary">
+          <div
+            className="w-8 h-8 rounded-full flex items-center justify-center text-sm font-medium text-white"
+            style={{ backgroundColor: getAvatarColor("AR") }}
+          >
             AR
           </div>
         </div>

frontend/src/components/ParticipantManager.tsx

@@ -3,38 +3,52 @@ 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 } from 'lucide-react';
+import { UserPlus, Trash2, User, Pencil, Check, X, AlertCircle } from 'lucide-react';
 import { useToast } from '@/hooks/use-toast';
+import { getAvatarColor } from '@/lib/utils';
 
 interface ParticipantManagerProps {
   participants: Participant[];
-  onAddParticipant: (participant: { name: string; email: string; icsLink: string }) => void;
+  onAddParticipant: (participant: { name: string; email: string; timezone: string; icsLink: string }) => void;
   onRemoveParticipant: (id: string) => void;
+  onUpdateParticipant?: (id: string, data: { timezone?: string; ics_url?: string }) => Promise<void>;
 }
 
 export const ParticipantManager = ({
   participants,
   onAddParticipant,
   onRemoveParticipant,
+  onUpdateParticipant,
 }: ParticipantManagerProps) => {
   const [name, setName] = useState('');
   const [email, setEmail] = useState('');
   const [icsLink, setIcsLink] = useState('');
+
+  // Edit state
+  const [editingId, setEditingId] = useState<string | null>(null);
+  const [editIcsLink, setEditIcsLink] = useState('');
+  const [isUpdating, setIsUpdating] = useState(false);
+
   const { toast } = useToast();
 
   const handleSubmit = (e: React.FormEvent) => {
     e.preventDefault();
 
-    if (!name.trim() || !email.trim() || !icsLink.trim()) {
+    if (!name.trim() || !email.trim()) {
       toast({
         title: "Missing fields",
-        description: "Please fill in all fields",
+        description: "Please fill in name and email",
         variant: "destructive",
       });
       return;
     }
 
-    onAddParticipant({ name: name.trim(), email: email.trim(), icsLink: icsLink.trim() });
+    onAddParticipant({
+      name: name.trim(),
+      email: email.trim(),
+      timezone: 'America/Toronto',
+      icsLink: icsLink.trim() || ''
+    });
     setName('');
     setEmail('');
     setIcsLink('');
@@ -45,6 +59,40 @@ export const ParticipantManager = ({
     });
   };
 
+  const startEditing = (participant: Participant) => {
+    setEditingId(participant.id);
+    setEditIcsLink(participant.icsLink || '');
+  };
+
+  const cancelEditing = () => {
+    setEditingId(null);
+    setEditIcsLink('');
+  };
+
+  const saveEditing = async (participantId: string) => {
+    if (!onUpdateParticipant) return;
+
+    setIsUpdating(true);
+    try {
+      await onUpdateParticipant(participantId, {
+        ics_url: editIcsLink || undefined,
+      });
+      toast({
+        title: "Participant updated",
+        description: "Changes saved successfully",
+      });
+      setEditingId(null);
+    } catch (error) {
+      toast({
+        title: "Update failed",
+        description: error instanceof Error ? error.message : "Unknown error",
+        variant: "destructive",
+      });
+    } finally {
+      setIsUpdating(false);
+    }
+  };
+
   const getInitials = (name: string) => {
     return name
       .split(' ')
@@ -64,7 +112,7 @@ export const ParticipantManager = ({
         </h3>
 
         <form onSubmit={handleSubmit} className="space-y-4">
-          <div className="grid gap-4 sm:grid-cols-3">
+          <div className="grid gap-4 sm:grid-cols-2 lg:grid-cols-3">
             <div className="space-y-2">
               <Label htmlFor="name">Name</Label>
               <Input
@@ -92,7 +140,7 @@ export const ParticipantManager = ({
               <Label htmlFor="icsLink">Calendar ICS Link</Label>
               <Input
                 id="icsLink"
-                placeholder="https://calendar.google.com/..."
+                placeholder="https://..."
                 value={icsLink}
                 onChange={(e) => setIcsLink(e.target.value)}
                 className="bg-background"
@@ -123,26 +171,106 @@ export const ParticipantManager = ({
             {participants.map((participant) => (
               <div
                 key={participant.id}
-                className="flex items-center justify-between p-4 bg-background rounded-lg border border-border"
+                className="p-4 bg-background rounded-lg border border-border"
               >
-                <div className="flex items-center gap-3">
+                {editingId === participant.id ? (
-                  <div className="w-10 h-10 rounded-full bg-primary/10 flex items-center justify-center text-sm font-medium text-primary">
+                  // Edit mode
-                    {getInitials(participant.name)}
+                  <div className="space-y-4">
-                  </div>
+                    <div className="flex items-center gap-3">
-                  <div>
+                      <div
-                    <div className="font-medium text-foreground">{participant.name}</div>
+                        className="w-10 h-10 rounded-full flex items-center justify-center text-sm font-medium text-white"
-                    <div className="text-sm text-muted-foreground">{participant.email}</div>
+                        style={{ backgroundColor: getAvatarColor(participant.name) }}
-                  </div>
+                      >
-                </div>
+                        {getInitials(participant.name)}
+                      </div>
+                      <div>
+                        <div className="font-medium text-foreground">{participant.name}</div>
+                        <div className="text-sm text-muted-foreground">{participant.email}</div>
+                      </div>
+                    </div>
 
-                <Button
+                    <div className="space-y-2">
-                  variant="ghost"
+                      <Label htmlFor={`edit-ics-${participant.id}`}>Calendar ICS Link</Label>
-                  size="icon"
+                      <Input
-                  onClick={() => onRemoveParticipant(participant.id)}
+                        id={`edit-ics-${participant.id}`}
-                  className="text-muted-foreground hover:text-destructive"
+                        value={editIcsLink}
-                >
+                        onChange={(e) => setEditIcsLink(e.target.value)}
-                  <Trash2 className="w-4 h-4" />
+                        placeholder="https://..."
-                </Button>
+                        className="bg-card"
+                      />
+                    </div>
+
+                    <div className="flex gap-2">
+                      <Button
+                        size="sm"
+                        onClick={() => saveEditing(participant.id)}
+                        disabled={isUpdating}
+                      >
+                        <Check className="w-4 h-4 mr-1" />
+                        {isUpdating ? 'Saving...' : 'Save'}
+                      </Button>
+                      <Button
+                        size="sm"
+                        variant="ghost"
+                        onClick={cancelEditing}
+                        disabled={isUpdating}
+                      >
+                        <X className="w-4 h-4 mr-1" />
+                        Cancel
+                      </Button>
+                    </div>
+                  </div>
+                ) : (
+                  // View mode
+                  <div className="flex items-center justify-between">
+                    <div className="flex items-center gap-3">
+                      <div
+                        className="w-10 h-10 rounded-full flex items-center justify-center text-sm font-medium text-white"
+                        style={{ backgroundColor: getAvatarColor(participant.name) }}
+                      >
+                        {getInitials(participant.name)}
+                      </div>
+                      <div>
+                        <div className="font-medium text-foreground">{participant.name}</div>
+                        <div className="text-sm text-muted-foreground flex flex-wrap gap-x-2">
+                          <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>
+                          ) : (
+                            <span className="text-amber-600 flex items-center gap-1">
+                              <AlertCircle className="w-3 h-3" />
+                              No calendar linked
+                            </span>
+                          )}
+                        </div>
+                      </div>
+                    </div>
+
+                    <div className="flex items-center gap-1">
+                      {onUpdateParticipant && (
+                        <Button
+                          variant="ghost"
+                          size="icon"
+                          onClick={() => startEditing(participant)}
+                          className="text-muted-foreground hover:text-foreground"
+                        >
+                          <Pencil className="w-4 h-4" />
+                        </Button>
+                      )}
+                      <Button
+                        variant="ghost"
+                        size="icon"
+                        onClick={() => onRemoveParticipant(participant.id)}
+                        className="text-muted-foreground hover:text-destructive"
+                      >
+                        <Trash2 className="w-4 h-4" />
+                      </Button>
+                    </div>
+                  </div>
+                )}
               </div>
             ))}
           </div>

frontend/src/components/ParticipantSelector.tsx

@@ -1,8 +1,8 @@
-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, User } from 'lucide-react';
+import { X, Plus, Search, AlertCircle } from 'lucide-react';
-import { cn } from '@/lib/utils';
+import { cn, getAvatarColor } from '@/lib/utils';
 
 interface ParticipantSelectorProps {
   participants: Participant[];
@@ -17,6 +17,19 @@ 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 +38,43 @@ 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) => {
@@ -45,38 +87,49 @@ export const ParticipantSelector = ({
   };
 
   return (
-    <div className="space-y-4">
+    <div ref={containerRef} 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" />
         <Input
+          ref={inputRef}
           placeholder="Search people..."
           value={searchQuery}
           onChange={(e) => {
             setSearchQuery(e.target.value);
+            setHighlightedIndex(0);
             setIsDropdownOpen(true);
           }}
           onFocus={() => setIsDropdownOpen(true)}
+          onKeyDown={handleKeyDown}
           className="pl-10 h-12 bg-background border-border"
         />
 
         {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) => (
+            {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 bg-primary/10 flex items-center justify-center text-xs font-medium text-primary">
+                <div
+                  className="w-8 h-8 rounded-full flex items-center justify-center text-xs font-medium text-white"
+                  style={{ backgroundColor: getAvatarColor(participant.name) }}
+                >
                   {getInitials(participant.name)}
                 </div>
                 <div>
                   <div className="font-medium text-foreground">{participant.name}</div>
                   <div className="text-xs text-muted-foreground">{participant.email}</div>
                 </div>
-                {!participant.connected && (
+                {!participant.icsLink && (
-                  <span className="ml-auto text-xs text-muted-foreground bg-muted px-2 py-0.5 rounded">
+                  <span className="ml-auto text-xs text-amber-600 flex items-center gap-1">
-                    Not connected
+                    <AlertCircle className="w-3 h-3" />
+                    No calendar
                   </span>
                 )}
               </button>
@@ -96,10 +149,16 @@ export const ParticipantSelector = ({
               )}
               style={{ animationDelay: `${index * 50}ms` }}
             >
-              <div className="w-6 h-6 rounded-full bg-primary/20 flex items-center justify-center text-xs font-medium">
+              <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"

frontend/src/components/ScheduleModal.tsx

@@ -1,5 +1,6 @@
 import { useState } from 'react';
 import { TimeSlot, Participant } from '@/types/calendar';
+import { scheduleMeeting } from '@/api/client';
 import {
   Dialog,
   DialogContent,
@@ -11,7 +12,7 @@ import { Input } from '@/components/ui/input';
 import { Textarea } from '@/components/ui/textarea';
 import { Label } from '@/components/ui/label';
 import { toast } from '@/hooks/use-toast';
-import { Calendar, Clock, Users, Send } from 'lucide-react';
+import { Calendar, Clock, Users, Send, AlertCircle } from 'lucide-react';
 
 interface ScheduleModalProps {
   isOpen: boolean;
@@ -34,7 +35,23 @@ export const ScheduleModal = ({
     return `${hour.toString().padStart(2, '0')}:00`;
   };
 
-  const handleSubmit = () => {
+  const formatDate = (dateStr: string) => {
+    const date = new Date(dateStr + 'T00:00:00');
+    return date.toLocaleDateString('en-US', { weekday: 'short', month: 'short', day: 'numeric' });
+  };
+
+  const isTooSoon = () => {
+    if (!slot) return false;
+    // Use UTC to match backend timezone
+    const startDateTime = new Date(`${slot.day}T${formatHour(slot.hour)}:00Z`);
+    const now = new Date();
+    const twoHoursFromNow = new Date(now.getTime() + 2 * 60 * 60 * 1000);
+    return startDateTime < twoHoursFromNow;
+  };
+
+  const tooSoon = isTooSoon();
+
+  const handleSubmit = async () => {
     if (!title.trim()) {
       toast({
         title: "Please enter a meeting title",
@@ -43,19 +60,41 @@ export const ScheduleModal = ({
       return;
     }
 
+    if (!slot) return;
+
     setIsSubmitting(true);
 
-    // Simulate API call
+    try {
-    setTimeout(() => {
+      // Calculate start and end times
-      setIsSubmitting(false);
+      // 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`);
+
+      await scheduleMeeting(
+        participants.map(p => p.id),
+        title,
+        notes,
+        startDateTime.toISOString(),
+        endDateTime.toISOString()
+      );
+
       toast({
         title: "Meeting scheduled",
-        description: "Invitations sent to all participants",
+        description: "Invitations sent via Email and Zulip",
       });
+
       setTitle('');
       setNotes('');
       onClose();
-    }, 1000);
+    } catch (error) {
+      toast({
+        title: "Scheduling failed",
+        description: error instanceof Error ? error.message : "Unknown error",
+        variant: "destructive",
+      });
+    } finally {
+      setIsSubmitting(false);
+    }
   };
 
   if (!slot) return null;
@@ -72,7 +111,7 @@ export const ScheduleModal = ({
           <div className="bg-accent/50 rounded-lg p-4 space-y-3">
             <div className="flex items-center gap-3 text-sm">
               <Calendar className="w-4 h-4 text-primary" />
-              <span className="font-medium">{slot.day}</span>
+              <span className="font-medium">{formatDate(slot.day)}</span>
             </div>
             <div className="flex items-center gap-3 text-sm">
               <Clock className="w-4 h-4 text-primary" />
@@ -109,12 +148,20 @@ export const ScheduleModal = ({
             </div>
           </div>
 
+          {/* Lead Time Warning */}
+          {tooSoon && (
+            <div className="flex items-center gap-2 p-3 bg-destructive/10 border border-destructive/20 rounded-lg text-sm text-destructive">
+              <AlertCircle className="w-4 h-4 flex-shrink-0" />
+              <span>Meetings must be scheduled at least 2 hours in advance</span>
+            </div>
+          )}
+
           {/* Actions */}
           <Button
             variant="schedule"
             className="w-full h-12"
             onClick={handleSubmit}
-            disabled={isSubmitting}
+            disabled={isSubmitting || tooSoon}
           >
             {isSubmitting ? (
               <span className="animate-pulse">Sending...</span>

frontend/src/components/TimezoneSelector.tsx

@@ -0,0 +1,217 @@
+import { useState, useEffect, useRef } from 'react';
+import { Input } from '@/components/ui/input';
+import { Search, Globe, ChevronDown } from 'lucide-react';
+import { cn } from '@/lib/utils';
+
+interface TimezoneSelectorProps {
+  value: string;
+  onChange: (timezone: string) => void;
+  className?: string;
+}
+
+// Get all IANA timezones
+const getAllTimezones = (): string[] => {
+  try {
+    return Intl.supportedValuesOf('timeZone');
+  } catch {
+    // Fallback for older browsers
+    return [
+      'UTC',
+      'America/New_York',
+      'America/Chicago',
+      'America/Denver',
+      'America/Los_Angeles',
+      'America/Toronto',
+      'America/Vancouver',
+      'Europe/London',
+      'Europe/Paris',
+      'Europe/Berlin',
+      'Asia/Tokyo',
+      'Asia/Shanghai',
+      'Asia/Singapore',
+      'Australia/Sydney',
+      'Pacific/Auckland',
+    ];
+  }
+};
+
+// Get UTC offset for a timezone
+const getTimezoneOffset = (timezone: string): string => {
+  try {
+    const now = new Date();
+    const formatter = new Intl.DateTimeFormat('en-US', {
+      timeZone: timezone,
+      timeZoneName: 'shortOffset',
+    });
+    const parts = formatter.formatToParts(now);
+    const offsetPart = parts.find((p) => p.type === 'timeZoneName');
+    return offsetPart?.value || '';
+  } catch {
+    return '';
+  }
+};
+
+// Get current time in a timezone
+const getCurrentTimeInTimezone = (timezone: string): string => {
+  try {
+    return new Intl.DateTimeFormat('en-US', {
+      timeZone: timezone,
+      hour: 'numeric',
+      minute: '2-digit',
+      hour12: true,
+    }).format(new Date());
+  } catch {
+    return '';
+  }
+};
+
+// Format timezone for display (e.g., "America/New_York" -> "New York")
+const formatTimezoneLabel = (timezone: string): string => {
+  const parts = timezone.split('/');
+  const city = parts[parts.length - 1];
+  return city.replace(/_/g, ' ');
+};
+
+const ALL_TIMEZONES = getAllTimezones();
+
+export const TimezoneSelector = ({
+  value,
+  onChange,
+  className,
+}: TimezoneSelectorProps) => {
+  const [searchQuery, setSearchQuery] = useState('');
+  const [isDropdownOpen, setIsDropdownOpen] = useState(false);
+  const [hoveredTimezone, setHoveredTimezone] = useState<string | null>(null);
+  const containerRef = useRef<HTMLDivElement>(null);
+
+  // Close dropdown when clicking outside
+  useEffect(() => {
+    const handleClickOutside = (event: MouseEvent) => {
+      if (containerRef.current && !containerRef.current.contains(event.target as Node)) {
+        setIsDropdownOpen(false);
+      }
+    };
+
+    document.addEventListener('mousedown', handleClickOutside);
+    return () => document.removeEventListener('mousedown', handleClickOutside);
+  }, []);
+
+  const filteredTimezones = ALL_TIMEZONES.filter((tz) => {
+    const query = searchQuery.toLowerCase();
+    const tzLower = tz.toLowerCase();
+    const labelLower = formatTimezoneLabel(tz).toLowerCase();
+    const offset = getTimezoneOffset(tz).toLowerCase();
+
+    return (
+      tzLower.includes(query) ||
+      labelLower.includes(query) ||
+      offset.includes(query)
+    );
+  });
+
+  const selectTimezone = (timezone: string) => {
+    onChange(timezone);
+    setSearchQuery('');
+    setIsDropdownOpen(false);
+  };
+
+  const selectedOffset = getTimezoneOffset(value);
+  const selectedLabel = formatTimezoneLabel(value);
+
+  return (
+    <div ref={containerRef} className={cn('relative', className)}>
+      <button
+        onClick={() => setIsDropdownOpen(!isDropdownOpen)}
+        className={cn(
+          'flex items-center gap-2 px-3 py-1.5 rounded-lg text-sm',
+          'bg-muted hover:bg-accent transition-colors',
+          'border border-transparent hover:border-border'
+        )}
+      >
+        <Globe className="w-4 h-4 text-muted-foreground" />
+        <span className="text-foreground font-medium">{selectedLabel}</span>
+        <span className="text-muted-foreground">{selectedOffset}</span>
+        <ChevronDown className={cn(
+          'w-4 h-4 text-muted-foreground transition-transform',
+          isDropdownOpen && 'rotate-180'
+        )} />
+      </button>
+
+      {isDropdownOpen && (
+        <div className="absolute z-20 right-0 mt-2 w-80 bg-popover border border-border rounded-lg shadow-popover animate-scale-in overflow-hidden">
+          <div className="p-2 border-b border-border">
+            <div className="relative">
+              <Search className="absolute left-3 top-1/2 -translate-y-1/2 w-4 h-4 text-muted-foreground" />
+              <Input
+                placeholder="Search timezone..."
+                value={searchQuery}
+                onChange={(e) => setSearchQuery(e.target.value)}
+                className="pl-10 h-9 bg-background border-border"
+                autoFocus
+              />
+            </div>
+          </div>
+
+          <div className="max-h-64 overflow-y-auto">
+            {filteredTimezones.length === 0 ? (
+              <div className="px-4 py-3 text-sm text-muted-foreground text-center">
+                No timezones found
+              </div>
+            ) : (
+              filteredTimezones.slice(0, 50).map((timezone) => {
+                const isSelected = timezone === value;
+                const offset = getTimezoneOffset(timezone);
+                const label = formatTimezoneLabel(timezone);
+                const isHovered = hoveredTimezone === timezone;
+
+                return (
+                  <button
+                    key={timezone}
+                    onClick={() => selectTimezone(timezone)}
+                    onMouseEnter={() => setHoveredTimezone(timezone)}
+                    onMouseLeave={() => setHoveredTimezone(null)}
+                    className={cn(
+                      'w-full px-4 py-2.5 flex items-center justify-between text-left transition-colors',
+                      isSelected ? 'bg-primary/10 text-primary' : 'hover:bg-accent'
+                    )}
+                  >
+                    <div className="flex items-center gap-3">
+                      <span className={cn(
+                        'text-xs font-mono w-16',
+                        isSelected ? 'text-primary' : 'text-muted-foreground'
+                      )}>
+                        {offset}
+                      </span>
+                      <div>
+                        <div className={cn(
+                          'font-medium',
+                          isSelected ? 'text-primary' : 'text-foreground'
+                        )}>
+                          {label}
+                        </div>
+                        <div className="text-xs text-muted-foreground">
+                          {timezone}
+                        </div>
+                      </div>
+                    </div>
+                    {isHovered && (
+                      <span className="text-xs text-muted-foreground animate-fade-in">
+                        {getCurrentTimeInTimezone(timezone)}
+                      </span>
+                    )}
+                  </button>
+                );
+              })
+            )}
+          </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/index.css

@@ -1,104 +1,119 @@
-@import url('https://fonts.googleapis.com/css2?family=DM+Sans:ital,opsz,wght@0,9..40,100..1000;1,9..40,100..1000&display=swap');
-
 @tailwind base;
 @tailwind components;
 @tailwind utilities;
 
 @layer base {
+  @font-face {
+    font-family: 'Inter';
+    font-style: normal;
+    font-weight: 400;
+    font-display: swap;
+    src: url('/fonts/inter-400.woff2') format('woff2');
+  }
+  @font-face {
+    font-family: 'Inter';
+    font-style: normal;
+    font-weight: 500;
+    font-display: swap;
+    src: url('/fonts/inter-500.woff2') format('woff2');
+  }
+  @font-face {
+    font-family: 'Inter';
+    font-style: normal;
+    font-weight: 600;
+    font-display: swap;
+    src: url('/fonts/inter-600.woff2') format('woff2');
+  }
+  @font-face {
+    font-family: 'Source Serif Pro';
+    font-style: normal;
+    font-weight: 400;
+    font-display: swap;
+    src: url('/fonts/source-serif-pro-400.woff2') format('woff2');
+  }
+  @font-face {
+    font-family: 'Source Serif Pro';
+    font-style: normal;
+    font-weight: 600;
+    font-display: swap;
+    src: url('/fonts/source-serif-pro-600.woff2') format('woff2');
+  }
+  @font-face {
+    font-family: 'Source Serif Pro';
+    font-style: normal;
+    font-weight: 700;
+    font-display: swap;
+    src: url('/fonts/source-serif-pro-700.woff2') format('woff2');
+  }
+
   :root {
-    --background: 210 20% 98%;
+    /* Greyhaven Colors converted to HSL */
-    --foreground: 222 47% 11%;
+    /* Light Mode Defaults */
+    --background: 60 9% 93%; /* #F0F0EC */
+    --foreground: 60 5% 8%;  /* #161614 */
 
-    --card: 0 0% 100%;
+    --card: 60 9% 97%;       /* #F9F9F7 */
-    --card-foreground: 222 47% 11%;
+    --card-foreground: 60 5% 8%;
 
-    --popover: 0 0% 100%;
+    --popover: 60 9% 97%;
-    --popover-foreground: 222 47% 11%;
+    --popover-foreground: 60 5% 8%;
 
-    --primary: 173 58% 39%;
+    --primary: 18 68% 51%;   /* #D95E2A (RGB 217 94 42) */
-    --primary-foreground: 0 0% 100%;
+    --primary-foreground: 60 9% 97%;
 
-    --secondary: 210 20% 96%;
+    --secondary: 60 9% 93%;
-    --secondary-foreground: 222 47% 11%;
+    --secondary-foreground: 60 3% 18%; /* #2F2F2C */
 
-    --muted: 210 20% 94%;
+    --muted: 60 5% 84%;      /* Darker than background for contrast */
-    --muted-foreground: 215 16% 47%;
+    --muted-foreground: 60 2% 34%; /* #575753 */
 
-    --accent: 173 58% 94%;
+    --accent: 60 9% 85%;       /* #DDD7 */
-    --accent-foreground: 173 58% 25%;
+    --accent-foreground: 60 5% 8%;
 
-    --destructive: 0 84% 60%;
+    --destructive: 0 57% 45%; /* #B43232 (RGB 180 50 50) */
-    --destructive-foreground: 0 0% 100%;
+    --destructive-foreground: 60 9% 97%;
 
-    --border: 214 32% 91%;
+    --border: 60 5% 77%;      /* #C4C4BD (RGB 196 196 189) */
-    --input: 214 32% 91%;
+    --input: 60 5% 77%;
-    --ring: 173 58% 39%;
+    --ring: 18 68% 51%;
 
-    --radius: 0.75rem;
+    --radius: 0.375rem;
 
-    /* Custom colors for heatmap */
+    /* Custom colors for heatmap - Updated to match system tags */
-    --availability-full: 142 71% 45%;
+    --availability-full: 142 76% 36%;  /* Tag Green */
-    --availability-partial: 48 96% 53%;
+    --availability-partial: 25 80% 65%; /* Tag Orange */
-    --availability-none: 215 16% 85%;
+    --availability-none: 0 0% 80%;      /* Grey */
+
+    /* Tag Colors */
+    --tag-orange: 25 80% 65%;
+    --tag-green: 142 76% 36%;
+    --tag-blue: 210 100% 60%;
+    --tag-purple: 270 70% 65%;
+    --tag-brown: 30 40% 50%;
+
+    /* Typography */
+    --font-serif: 'Source Serif Pro', Georgia, 'Times New Roman', serif;
+    --font-display: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
 
     /* Shadows */
-    --shadow-sm: 0 1px 2px 0 hsl(222 47% 11% / 0.05);
+    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
-    --shadow-md: 0 4px 6px -1px hsl(222 47% 11% / 0.1), 0 2px 4px -2px hsl(222 47% 11% / 0.1);
+    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
-    --shadow-lg: 0 10px 15px -3px hsl(222 47% 11% / 0.1), 0 4px 6px -4px hsl(222 47% 11% / 0.1);
+    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
-    --shadow-xl: 0 20px 25px -5px hsl(222 47% 11% / 0.1), 0 8px 10px -6px hsl(222 47% 11% / 0.1);
+    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);
-
+    
-    --sidebar-background: 0 0% 98%;
+    --sidebar-background: 60 9% 93%;
-    --sidebar-foreground: 240 5.3% 26.1%;
+    --sidebar-foreground: 60 5% 8%;
-    --sidebar-primary: 240 5.9% 10%;
+    --sidebar-primary: 18 68% 51%;
-    --sidebar-primary-foreground: 0 0% 98%;
+    --sidebar-primary-foreground: 60 9% 97%;
-    --sidebar-accent: 240 4.8% 95.9%;
+    --sidebar-accent: 60 9% 85%;
-    --sidebar-accent-foreground: 240 5.9% 10%;
+    --sidebar-accent-foreground: 60 5% 8%;
-    --sidebar-border: 220 13% 91%;
+    --sidebar-border: 60 5% 77%;
-    --sidebar-ring: 217.2 91.2% 59.8%;
+    --sidebar-ring: 18 68% 51%;
   }
 
-  .dark {
+  /* Dark mode intentionally removed/reset to match light mode system for now, 
-    --background: 222 47% 6%;
+     or you can define a proper dark mode if required. 
-    --foreground: 210 20% 98%;
+     Keeping it simple as per previous apps. */
-
-    --card: 222 47% 8%;
-    --card-foreground: 210 20% 98%;
-
-    --popover: 222 47% 8%;
-    --popover-foreground: 210 20% 98%;
-
-    --primary: 173 58% 45%;
-    --primary-foreground: 0 0% 100%;
-
-    --secondary: 222 47% 14%;
-    --secondary-foreground: 210 20% 98%;
-
-    --muted: 222 47% 14%;
-    --muted-foreground: 215 16% 65%;
-
-    --accent: 173 58% 15%;
-    --accent-foreground: 173 58% 75%;
-
-    --destructive: 0 62% 30%;
-    --destructive-foreground: 210 20% 98%;
-
-    --border: 222 47% 17%;
-    --input: 222 47% 17%;
-    --ring: 173 58% 45%;
-
-    --availability-full: 142 71% 35%;
-    --availability-partial: 48 96% 40%;
-    --availability-none: 222 47% 20%;
-
-    --sidebar-background: 240 5.9% 10%;
-    --sidebar-foreground: 240 4.8% 95.9%;
-    --sidebar-primary: 224.3 76.3% 48%;
-    --sidebar-primary-foreground: 0 0% 100%;
-    --sidebar-accent: 240 3.7% 15.9%;
-    --sidebar-accent-foreground: 240 4.8% 95.9%;
-    --sidebar-border: 240 3.7% 15.9%;
-    --sidebar-ring: 217.2 91.2% 59.8%;
-  }
 }
 
 @layer base {
@@ -107,8 +122,12 @@
   }
 
   body {
-    @apply bg-background text-foreground font-sans antialiased;
+    @apply bg-background text-foreground antialiased;
-    font-family: 'DM Sans', sans-serif;
+    font-family: var(--font-display);
+  }
+
+  h1, h2, h3, h4, h5, h6 {
+    font-family: var(--font-serif);
   }
 }
 

frontend/src/lib/utils.ts

@@ -4,3 +4,18 @@ import { twMerge } from "tailwind-merge";
 export function cn(...inputs: ClassValue[]) {
   return twMerge(clsx(inputs));
 }
+
+export function getAvatarColor(name?: string): string {
+  const colors = [
+    'hsl(var(--tag-green))',
+    'hsl(var(--tag-blue))',
+    'hsl(var(--tag-orange))',
+    'hsl(var(--tag-purple))',
+    'hsl(var(--tag-brown))',
+  ];
+
+  if (!name) return colors[0];
+
+  const hash = name.split('').reduce((acc, char) => acc + char.charCodeAt(0), 0);
+  return colors[hash % colors.length];
+}

frontend/src/pages/Index.tsx

@@ -1,4 +1,5 @@
 import { useState, useEffect } from 'react';
+import { useNavigate, useLocation } from 'react-router-dom';
 import { Header } from '@/components/Header';
 import { ParticipantSelector } from '@/components/ParticipantSelector';
 import { ParticipantManager } from '@/components/ParticipantManager';
@@ -19,6 +20,7 @@ import { useToast } from '@/hooks/use-toast';
 import {
   fetchParticipants,
   createParticipant,
+  updateParticipant,
   deleteParticipant,
   fetchAvailability,
   syncCalendars,
@@ -40,22 +42,41 @@ function apiToParticipant(p: ParticipantAPI): Participant {
     id: p.id,
     name: p.name,
     email: p.email,
+    timezone: p.timezone,
     icsLink: p.ics_url,
     connected: true,
   };
 }
 
-const Index = () => {
+interface IndexProps {
+  defaultTab?: string;
+}
+
+const Index = ({ defaultTab = 'schedule' }: IndexProps) => {
+  const navigate = useNavigate();
+  const location = useLocation();
+  const [activeTab, setActiveTab] = useState(defaultTab);
   const [participants, setParticipants] = useState<Participant[]>([]);
   const [selectedParticipants, setSelectedParticipants] = useState<Participant[]>([]);
   const [availabilitySlots, setAvailabilitySlots] = useState<TimeSlot[]>([]);
   const [selectedSlot, setSelectedSlot] = useState<TimeSlot | null>(null);
   const [isModalOpen, setIsModalOpen] = useState(false);
   const [settings, setSettings] = useState<SettingsState>(defaultSettings);
+  const [weekOffset, setWeekOffset] = useState(0);
   const [isLoading, setIsLoading] = useState(false);
   const [isSyncing, setIsSyncing] = useState(false);
   const { toast } = useToast();
 
+  useEffect(() => {
+    // Sync internal state if prop changes (e.g. browser back button)
+    setActiveTab(defaultTab);
+  }, [defaultTab]);
+
+  const handleTabChange = (value: string) => {
+    setActiveTab(value);
+    navigate(`/${value}`);
+  };
+
   useEffect(() => {
     const stored = localStorage.getItem(SETTINGS_KEY);
     if (stored) {
@@ -81,7 +102,7 @@ const Index = () => {
     } else {
       setAvailabilitySlots([]);
     }
-  }, [selectedParticipants]);
+  }, [selectedParticipants, weekOffset]);
 
   const loadParticipants = async () => {
     try {
@@ -100,7 +121,7 @@ const Index = () => {
     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({
@@ -113,12 +134,13 @@ const Index = () => {
     }
   };
 
-  const handleAddParticipant = async (data: { name: string; email: string; icsLink: string }) => {
+  const handleAddParticipant = async (data: { name: string; email: string; timezone: string; icsLink: string }) => {
     try {
       const created = await createParticipant({
         name: data.name,
         email: data.email,
-        ics_url: data.icsLink,
+        timezone: data.timezone,
+        ics_url: data.icsLink || undefined,
       });
       setParticipants((prev) => [...prev, apiToParticipant(created)]);
       toast({
@@ -151,6 +173,16 @@ const Index = () => {
     }
   };
 
+  const handleUpdateParticipant = async (id: string, data: { timezone?: string; ics_url?: string }) => {
+    const updated = await updateParticipant(id, data);
+    setParticipants((prev) =>
+      prev.map((p) => (p.id === id ? apiToParticipant(updated) : p))
+    );
+    setSelectedParticipants((prev) =>
+      prev.map((p) => (p.id === id ? apiToParticipant(updated) : p))
+    );
+  };
+
   const handleSyncCalendars = async () => {
     setIsSyncing(true);
     try {
@@ -183,22 +215,28 @@ const Index = () => {
       <Header />
 
       <main className="container max-w-5xl mx-auto px-4 py-8">
-        <Tabs defaultValue="schedule" className="space-y-6">
+        <Tabs value={activeTab} onValueChange={handleTabChange} className="space-y-6">
-          <TabsList className="grid w-full max-w-md mx-auto grid-cols-2">
+          <TabsList className="grid w-full max-w-md mx-auto grid-cols-2 bg-muted p-1 rounded-xl">
-            <TabsTrigger value="participants" className="flex items-center gap-2">
+            <TabsTrigger
+              value="participants"
+              className="flex items-center gap-2 rounded-lg data-[state=active]:bg-background data-[state=active]:text-foreground data-[state=active]:shadow-sm transition-all"
+            >
               <Users className="w-4 h-4" />
-              Participants
+              People
             </TabsTrigger>
-            <TabsTrigger value="schedule" className="flex items-center gap-2">
+            <TabsTrigger
+              value="schedule"
+              className="flex items-center gap-2 rounded-lg data-[state=active]:bg-background data-[state=active]:text-foreground data-[state=active]:shadow-sm transition-all"
+            >
               <CalendarDays className="w-4 h-4" />
               Schedule
             </TabsTrigger>
           </TabsList>
 
-          <TabsContent value="participants" className="animate-fade-in">
+          <TabsContent value="participants" className="animate-fade-in focus-visible:outline-none">
             <div className="text-center mb-6">
               <h2 className="text-3xl font-bold text-foreground mb-2">
-                Manage Participants
+                Manage People
               </h2>
               <p className="text-muted-foreground">
                 Add team members with their calendar ICS links
@@ -209,6 +247,7 @@ const Index = () => {
               participants={participants}
               onAddParticipant={handleAddParticipant}
               onRemoveParticipant={handleRemoveParticipant}
+              onUpdateParticipant={handleUpdateParticipant}
             />
           </TabsContent>
 
@@ -265,7 +304,7 @@ const Index = () => {
                   <Users className="w-12 h-12 mx-auto mb-4 text-muted-foreground opacity-50" />
                   <h3 className="text-lg font-medium text-foreground mb-2">No participants yet</h3>
                   <p className="text-muted-foreground">
-                    Add participants in the Participants tab to start scheduling.
+                    Add people in the People tab to start scheduling.
                   </p>
                 </div>
               ) : (
@@ -287,6 +326,8 @@ const Index = () => {
                     onSlotSelect={handleSlotSelect}
                     showPartialAvailability={settings.showPartialAvailability}
                     isLoading={isLoading}
+                    weekOffset={weekOffset}
+                    onWeekOffsetChange={setWeekOffset}
                   />
                 </>
               )}

frontend/src/types/calendar.ts

@@ -2,6 +2,7 @@ export interface Participant {
   id: string;
   name: string;
   email: string;
+  timezone: string;
   icsLink?: string;
   avatar?: string;
   connected: boolean;
@@ -10,6 +11,7 @@ export interface Participant {
 export interface TimeSlot {
   day: string;
   hour: number;
+  start_time: string;
   availability: 'full' | 'partial' | 'none';
   availableParticipants: string[];
 }

frontend/tailwind.config.ts

@@ -14,7 +14,8 @@ export default {
     },
     extend: {
       fontFamily: {
-        sans: ['DM Sans', 'system-ui', 'sans-serif'],
+        sans: ['Inter', 'system-ui', 'sans-serif'],
+        serif: ['Source Serif Pro', 'Georgia', 'serif'],
       },
       colors: {
         border: "hsl(var(--border))",