*{box-sizing:border-box;margin:0;padding:0}body{color:#333;background:#f0f2f5;font-family:system-ui,-apple-system,sans-serif}#root{flex-direction:column;width:100%;max-width:800px;min-height:100vh;margin:0 auto;display:flex}.back-btn{color:#666;cursor:pointer;background:0 0;border:1px solid #ddd;border-radius:6px;align-self:flex-start;padding:8px 16px;font-size:14px}.back-btn:hover{color:#333;background:#e8e8e8}.login-container{flex-direction:column;justify-content:center;align-items:center;gap:20px;min-height:100vh;padding:20px;display:flex}.login-container h1{color:#333;font-size:2rem}.login-container form{flex-direction:column;gap:12px;width:300px;display:flex}.login-container input{color:#333;background:#fff;border:1px solid #ddd;border-radius:8px;padding:10px 14px;font-size:16px}.login-container input:focus{border-color:#4a90d9;outline:none;box-shadow:0 0 0 2px #4a90d926}.login-container button[type=submit]{color:#fff;cursor:pointer;background:#4a90d9;border:none;border-radius:8px;padding:10px;font-size:16px}.login-container button[type=submit]:hover{background:#3a7bc8}.error{color:#e74c3c;font-size:14px}.toggle{color:#888;font-size:14px}.toggle button{color:#4a90d9;cursor:pointer;background:0 0;border:none;font-size:14px;text-decoration:underline}.chat-container{background:#fff;flex-direction:column;height:100vh;display:flex;box-shadow:0 0 20px #0000000f}.chat-header{color:#fff;background:#4a90d9;justify-content:space-between;align-items:center;padding:14px 20px;display:flex}.chat-header h2{color:#fff;font-size:1.2rem}.chat-header span{color:#ffffffd9;margin-right:12px;font-size:14px}.chat-header strong{color:#fff}.chat-header button{color:#fff;cursor:pointer;background:#fff3;border:none;border-radius:4px;padding:6px 12px;font-size:13px}.chat-header button:hover{background:#ffffff4d}.chat-messages{background:#f0f2f5;flex-direction:column;flex:1;gap:8px;padding:16px;display:flex;overflow-y:auto}.message{background:#fff;border-radius:12px;align-self:flex-start;max-width:70%;padding:8px 12px;box-shadow:0 1px 2px #00000014}.message.mine{background:#d9ecff;align-self:flex-end}.message-user{color:#4a90d9;margin-bottom:2px;font-size:12px;font-weight:600;display:block}.message.mine .message-user{color:#2e6db4}.message-text{color:#333;word-break:break-word;font-size:15px}.message-time{color:#aaa;text-align:right;margin-top:4px;font-size:11px;display:block}.chat-input{background:#fff;border-top:1px solid #e8e8e8;gap:8px;padding:12px 16px;display:flex}.chat-input input{color:#333;background:#f0f2f5;border:1px solid #ddd;border-radius:20px;flex:1;padding:10px 14px;font-size:16px}.chat-input input:focus{border-color:#4a90d9;outline:none}.chat-input button{color:#fff;cursor:pointer;background:#4a90d9;border:none;border-radius:20px;padding:10px 20px;font-size:16px}.chat-input button:hover{background:#3a7bc8}.login-btn{color:#fff;cursor:pointer;background:#fff3;border:none;border-radius:6px;padding:8px 16px;font-size:14px}.login-btn:hover{background:#ffffff4d}.guest-bar{color:#888;justify-content:center;align-items:center;gap:12px;font-size:14px;display:flex}.guest-bar .login-btn{color:#fff;background:#4a90d9}.guest-bar .login-btn:hover{background:#3a7bc8}