body{font-family:Arial,sans-serif;background:#f5f5f5}.container{max-width:800px;margin:auto;padding:20px}.upload{margin-bottom:20px}.chat{background:#fff;padding:10px;border-radius:8px}.messages{height:400px;overflow-y:auto}.message{margin-bottom:10px}.message.user{text-align:right}.message.assistant{text-align:left}.input-box{display:flex;gap:10px}input{flex:1;padding:8px}button{padding:8px 12px}.sources{font-size:12px;color:gray}