* { box-sizing: border-box; }
        body {
            font-family: system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
            background: #f5f5f5;
            margin: 0;
            min-height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
            padding: 16px;
        }
        .login-card {
            background: white;
            border-radius: 32px;
            padding: 32px 24px;
            box-shadow: 0 8px 24px rgba(0,0,0,0.05);
            width: 100%;
            max-width: 350px;
        }
        h2 {
            text-align: center;
            font-size: 28px;
            font-weight: 600;
            color: #1a1a1a;
            margin: 0 0 24px 0;
        }
        .form-group {
            margin-bottom: 20px;
        }
        label {
            display: block;
            font-size: 15px;
            font-weight: 500;
            color: #444;
            margin-bottom: 6px;
            padding-left: 8px;
        }
        input {
            width: 100%;
            padding: 16px;
            border: 1px solid #ddd;
            border-radius: 50px;
            font-size: 16px;
            background: #fafafa;
            transition: border-color 0.2s;
        }
        input:focus {
            outline: none;
            border-color: #007aff;
            background: white;
        }
        .captcha-row {
            display: flex;
            gap: 10px;
            align-items: center;
        }
        .captcha-row input {
            flex: 1;
        }
        .captcha-img {
            width: 100px;
            height: 40px;
            border-radius: 20px;
            cursor: pointer;
            border: 1px solid #ddd;
            background: #f0f0f0;
        }
        button {
            width: 100%;
            padding: 16px;
            background: #007aff;
            color: white;
            border: none;
            border-radius: 50px;
            font-size: 18px;
            font-weight: 600;
            cursor: pointer;
            margin-top: 8px;
            box-shadow: 0 4px 8px rgba(0,122,255,0.2);
            transition: background 0.2s;
        }
        button:active {
            background: #005bbf;
        }
        .error-message {
            background: #ffebee;
            color: #c62828;
            padding: 12px 16px;
            border-radius: 30px;
            margin-bottom: 20px;
            text-align: center;
            font-weight: 500;
            font-size: 15px;
            border: 1px solid #ffcdd2;
        }
        .footer-note {
            text-align: center;
            margin-top: 24px;
            color: #888;
            font-size: 13px;
        }
        .refresh-link {
            text-align: right;
            font-size: 13px;
            margin-top: 4px;
        }
        .refresh-link a {
            color: #007aff;
            text-decoration: none;
        }