body{margin:0;font-family:system-ui,sans-serif;background:#f4f6f8}.app{max-width:800px;margin:auto;padding:20px}.title{text-align:center}.chat-container{background:#fff;border-radius:8px;padding:10px;display:flex;flex-direction:column;height:80vh}.messages{flex:1;overflow-y:auto;padding:10px}.message{margin-bottom:10px;display:flex}.message.user{justify-content:flex-end}.message.assistant{justify-content:flex-start}.bubble{max-width:70%;padding:10px 14px;border-radius:16px;line-height:1.4}.user .bubble{background:#007bff;color:#fff}.assistant .bubble{background:#e5e7eb}.input-box{display:flex;gap:10px;padding:10px}.input-box input{flex:1;padding:10px;font-size:16px}.input-box button{padding:10px 16px;font-size:16px}