/* demo UI alignment — real styles from demo */
* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'PingFang SC', 'Microsoft YaHei', sans-serif;
        }

        body {
            background: linear-gradient(35deg, #ffffff 60%, #9bb8ff 100%);
            min-height: 100vh;
            display: flex;
            flex-direction: column;
            padding: 20px 12px;
        }
        
        .page-container {
            max-width: 420px;
            margin: 0 auto;
            flex: 1;
            display: flex;
            align-items: center;
            justify-content: center;
        }

        .login-container {
            width: 100%;
            background-color: white;
            border-radius: 16px;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
            overflow: hidden;
            animation: fadeIn 0.5s ease;
        }

        @keyframes fadeIn {
            from {
                opacity: 0;
                transform: translateY(20px);
            }

            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        .form-header {
            padding-top: 38px;
            text-align: center;
        }

        .form-header img {
            max-width: 50%;
            height: auto;
            display: block;
            margin: 0 auto;
        }

        .form-body {
            padding: 30px;
        }

        .form-group {
            margin-bottom: 20px;
        }

        .form-group label {
            display: block;
            margin-bottom: 8px;
            font-size: 14px;
            color: #555;
            font-weight: 500;
        }

        .form-group input {
            width: 100%;
            padding: 12px 15px;
            border: 1px solid #e0e0e0;
            border-radius: 8px;
            font-size: 14px;
            transition: all 0.3s;
            background-color: #f9f9f9;
        }

        .form-group input:focus {
            border-color: #5b8cff;
            outline: none;
            box-shadow: 0 0 0 3px rgba(91, 140, 255, 0.2);
            background-color: white;
        }

        .btn {
            width: 100%;
            padding: 14px;
            border: none;
            border-radius: 8px;
            font-size: 16px;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s;
            margin-top: 10px;
        }

        .btn-register {
            background: linear-gradient(to right, #5b8cff, #5b8cff);
            color: white;
            box-shadow: 0 4px 15px rgba(91, 140, 255, 0.3);
        }

        .btn-login {
            background-color: white;
            color: #5b8cff;
            border: 1px solid #5b8cff;
        }

        .btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 6px 20px rgba(91, 140, 255, 0.4);
        }

        .btn:active {
            transform: translateY(0);
        }

        .message {
            padding: 12px;
            margin-bottom: 20px;
            border-radius: 8px;
            text-align: center;
            font-size: 14px;
            animation: fadeIn 0.3s ease;
            display: none;
        }
        
        .message:not(.hidden) {
            display: block;
            animation: fadeIn 0.3s ease;
        }

        .error {
            background-color: #e8f0ff;
            color: #f44336;
            border-left: 4px solid #f44336;
        }

        .success {
            background-color: #e8f5e9;
            color: #4caf50;
            border-left: 4px solid #4caf50;
        }

        .login-link {
            text-align: center;
            margin-top: 20px;
            font-size: 14px;
            color: #666;
        }

        .login-link a {
            color: #5b8cff;
            font-weight: 600;
            text-decoration: none;
            transition: all 0.2s;
        }

        .login-link a:hover {
            color: #4a7ae8;
            text-decoration: underline;
        }

        .validation-message {
            font-size: 12px;
            height: 0;
            overflow: hidden;
            transition: all 0.3s ease;
        }

        .validation-error {
            color: #f44336;
            background-color: #e8f0ff;
            padding: 3px 8px;
            margin-top: 5px;
            border-radius: 4px;
            height: auto;
        }

        .btn:disabled {
            opacity: 0.6;
            cursor: not-allowed;
            transform: none !important;
            box-shadow: none !important;
        }

        .gender-options {
            display: flex;
            justify-content: center;
            margin-top: 8px;
        }

        .gender-option {
            position: relative;
            padding: 0;
            border: 2px solid #e0e0e0;
            border-radius: 50%;
            background: white;
            cursor: pointer;
            transition: all 0.3s ease;
            width: 50px;
            height: 50px;
            margin: 0 30px;
            display: block;
        }

        .gender-option:hover {
            transform: scale(1.05);
        }

        .gender-option.selected {
            border-color: currentColor;
            transform: scale(1.08);
            box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
        }

        .gender-option.male {
            color: #3b82f6;
        }

        .gender-option.male.selected {
            background: #93c5fd;
            color: white;
        }

        .gender-option.female {
            color: #fbcfe8;
        }

        .gender-option.female.selected {
            background: #fbcfe8;
            color: white;
        }

        .gender-icon {
            font-size: 20px;
            position: absolute;
            top: 52%;
            left: 50%;
            transform: translate(-50%, -50%);
            line-height: 1;
            display: block;
        }

        .gender-label {
            display: none;
        }

        input[type="radio"][name="gender"] {
            display: none;
        }
        
        footer {
            position: relative;
            text-align: center;
            font-size: 12px;
            color: #666;
            padding: 20px 0;
        }
        
        footer a {
            color: #5b8cff;
            text-decoration: none;
            font-weight: 600;
        }
        
        footer a:hover {
            color: #4a7ae8;
        }