body{margin:0;font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif;background:#f3f4f6;color:#111827}.container{max-width:900px;margin:24px auto;background:#fff;border:1px solid #e5e7eb;border-radius:12px;box-shadow:0 4px 12px #0000000d;overflow:hidden}.header{padding:16px 20px;border-bottom:1px solid #e5e7eb;display:flex;align-items:center;justify-content:space-between}.header h1{margin:0;font-size:1.05rem}.messages{padding:16px;max-height:70vh;overflow-y:auto;background:#fafafa}.msg{padding:12px 14px;border-radius:10px;margin-bottom:10px;line-height:1.5;animation:fadeIn .15s ease;white-space:pre-wrap;word-break:break-word}.msg.user{background:#e0f2fe;border:1px solid #bae6fd}.msg.assistant{background:#f3f4f6;border:1px solid #e5e7eb}.inputBar{display:flex;gap:8px;padding:12px;border-top:1px solid #e5e7eb;background:#f9fafb}.inputBar input{flex:1;padding:10px 12px;font-size:1rem;border:1px solid #d1d5db;border-radius:10px;outline:none}.inputBar input:focus{border-color:#3b82f6}.btn{background:#3b82f6;color:#fff;border:none;border-radius:10px;padding:10px 16px;cursor:pointer}.btn:hover{background:#2563eb}@keyframes fadeIn{0%{opacity:0;transform:translateY(6px)}to{opacity:1;transform:translateY(0)}}