:root {
            --primary-color: #007bff;
            --background-color: #f8f9fa;
            --text-color: #343a40;
            --input-border-color: #ced4da;
            --success-color: #28a745;
            --danger-color: #dc3545;
        }

        body {
            margin: 0;
            font-family: 'Noto Sans TC', sans-serif;
            background-color: var(--background-color);
            color: var(--text-color);
            line-height: 1.6;
        }

        .navbar {
            background-color: #fff;
            padding: 0.75rem 2rem;
            box-shadow: 0 2px 4px rgba(0,0,0,0.05);
            font-weight: 700;
        }
        
        .navbar a {
            color: var(--primary-color);
            text-decoration: none;
            font-size: 1rem;
        }

        .container {
            padding: 2rem;
            max-width: 700px;
            margin: 2rem auto;
            background-color: #fff;
            border-radius: 8px;
            box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
        }

        h1 {
            font-weight: 700;
            color: var(--primary-color);
            margin-bottom: 2rem;
            text-align: center;
        }

        .form-group {
            margin-bottom: 1.5rem;
        }

        .form-group label {
            display: block;
            margin-bottom: 0.5rem;
            font-weight: 700;
        }
        
        .form-group label .required {
            color: var(--danger-color);
            margin-left: 4px;
        }

        .form-control {
            width: 100%;
            padding: 0.75rem;
            font-size: 1rem;
            border: 1px solid var(--input-border-color);
            border-radius: 4px;
            box-sizing: border-box;
            transition: border-color 0.2s, box-shadow 0.2s;
        }

        .form-control:focus {
            outline: none;
            border-color: var(--primary-color);
            box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.25);
        }
        
        textarea.form-control {
            min-height: 120px;
            resize: vertical;
        }

        .btn {
            display: inline-block;
            width: 100%;
            padding: 0.8rem 1rem;
            font-size: 1.2rem;
            font-weight: 700;
            color: #fff;
            background-color: var(--primary-color);
            border: none;
            border-radius: 4px;
            cursor: pointer;
            text-align: center;
            transition: background-color 0.2s;
        }

        .btn:hover {
            background-color: #0056b3;
        }
        
        .btn:disabled {
            background-color: #6c757d;
            cursor: not-allowed;
        }
        
        .spinner {
            display: inline-block;
            width: 1rem;
            height: 1rem;
            vertical-align: text-bottom;
            border: .2em solid currentColor;
            border-right-color: transparent;
            border-radius: 50%;
            animation: spinner-border .75s linear infinite;
            margin-left: 8px;
        }
        
        .spinner.hidden {
            display: none;
        }

        @keyframes spinner-border {
            to { transform: rotate(360deg); }
        }

        .site-footer {
            background-color: #e9ecef;
            padding: 1.5rem 2rem;
            margin-top: 3rem;
            text-align: center;
            font-size: 0.9rem;
            color: #6c757d;
        }
        .footer-container a {
            color: #6c757d;
            text-decoration: none;
            margin: 0 10px;
        }
        .footer-container a:hover {
            text-decoration: underline;
        }
        .footer-separator {
            color: #ced4da;
        }
        .footer-contact {
            margin-top: 1rem;
        }
        
        .nav-link-spacing {
            margin-left: 1.5rem;
        }

        @media (min-width: 768px) {
            .navbar a {
                font-size: 1.2rem;
            }
        }