:root {
            --primary-color: #4e73df;
            --secondary-color: #858796;
            --success-color: #1cc88a;
            --info-color: #36b9cc;
            --warning-color: #f6c23e;
            --danger-color: #e74a3b;
        }
        
        .ElementId{
            display: none;
        }
        
        .form-label {
            color: #374151;
            font-weight: 500;
            margin-bottom: 8px;
            font-size: 14px;
        }
        
        .mb-3 {
            margin-bottom: 20px;
        }
        
        body {
            background: #f5f7fa;
            min-height: 100vh;
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
            display: flex;
            align-items: center;
            justify-content: center;
            margin: 0;
            padding: 20px;
        }
        .btn-sign-up {
            background: var(--primary-color);
            color: white;
            border: none;
            border-radius: 4px;
            padding: 10px 25px;
            font-weight: 600;
        }
        
      
        .auth-container {
            width: 100%;
            max-width: 400px;
            margin: 0;
            padding: 40px;
            background: #ffffff;
            border-radius: 12px;
            box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
            border: 1px solid #e8ecf0;
        }
        
        .auth-header {
            text-align: center;
        }
        
        .auth-header h2 {
            color: #333;
            font-weight: 600;
            margin-bottom: 30px;
            font-size: 1.5rem;
            text-align: center;
        }
        
        .logo-container {
            text-align: center;
            margin-bottom: 20px;
        }
        
        .auth-logo {
            max-width: 120px;
            height: auto;
            margin: 0 auto;
            display: block;
        }
        .btn-login{
            color: #3b82f6;
            border: 1px solid #3b82f6;
            border-radius: 6px;
            padding: 10px 25px;
            transition: all 0.2s ease;
        }
        .auth-header p {
            color: #6b7280;
            font-size: 0.9rem;
            text-align: center;
        }
        
        .form-control {
            height: 48px;
            border-radius: 6px;
            border: 1px solid #d1d5db;
            padding: 12px 16px;
            transition: all 0.2s ease;
            background: #ffffff;
            font-size: 14px;
        }
        
        .form-control:focus {
            border-color: #3b82f6;
            box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
            outline: none;
        }
        
        .btn-primary {
            background: #3b82f6;
            border: none;
            height: 48px;
            font-weight: 500;
            transition: all 0.2s ease;
            border-radius: 6px;
            font-size: 14px;
        }
        
        .btn-primary:hover {
            background: #2563eb;
        }
        
        .form-check-input:checked {
            background-color: #3b82f6;
            border-color: #3b82f6;
        }
        
        .auth-footer {
            text-align: center;
            margin-top: 24px;
            color: #6b7280;
            font-size: 14px;
        }
        
        .auth-footer a {
            color: #3b82f6;
            text-decoration: none;
            font-weight: 500;
            transition: all 0.2s ease;
        }
        
        .auth-footer a:hover {
            color: #2563eb;
            text-decoration: underline;
        }
        
        /* 登录页面容器 */
        .auth-wrapper {
            display: flex;
            align-items: center;
            justify-content: center;
            width: 100%;
            max-width: 400px;
            margin: 0 auto;
        }
        
        .auth-promo {
            display: none;
        }
        
        .auth-promo-title {
            font-size: 2.5rem;
            font-weight: 700;
            margin-bottom: 60px;
            text-shadow: 0 2px 10px rgba(0, 0, 0, 0.5);
        }
        
        .auth-promo-subtitle {
            opacity: 0.9;
            text-shadow: 0 2px 8px rgba(0, 0, 0, 0.7);
            line-height: 1.6;
        }
        
        
        
        .btn-sign-up:hover {
            box-shadow: 0 8px 25px var(--primary-color);
            color: white;
        }
        
        .btn-login:hover {
            color: #2563eb;
            background: rgba(59, 130, 246, 0.05);
            border-color: #2563eb;
        }
        .input-group-text {
            background-color: #f9fafb;
            border: 1px solid #d1d5db;
            color: #6b7280;
            border-radius: 6px 0 0 6px;
        }
        
        /* 确保input-group中的元素在同一行 */
        .input-group {
            display: flex;
            flex-wrap: nowrap;
            align-items: stretch;
        }
        
        .input-group .form-control {
            flex: 1;
            border-radius: 0;
        }
        
        .input-group .btn {
            border-radius: 0 6px 6px 0;
            white-space: nowrap;
            flex-shrink: 0;
        }
        
        .input-group .input-group-text + .form-control {
            border-left: none;
        }
        
        .input-group .form-control + .btn {
            border-left: none;
        }
        .nav-link {
            margin: 0 15px;
            padding: .5rem;
        }
       
        .captcha-img {
            height: 48px;
            cursor: pointer;
            border-radius: 0 6px 6px 0;
            transition: all 0.2s ease;
            border: 1px solid #d1d5db;
            border-left: none;
        }
        
        .captcha-img:hover {
            opacity: 0.8;
        }
        
        /* 隐藏导航栏 */
        .navbar {
            display: none;
        }
        
        .main-content {
            margin-top: 0;
            width: 100%;
            display: flex;
            align-items: center;
            justify-content: center;
            min-height: 100vh;
        }
        
        @media (max-width: 768px) {
            body {
                padding-right: 0;
                justify-content: center;
            }
            
            .auth-wrapper {
                flex-direction: column;
                max-width: 100%;
            }
            
            .auth-promo {
                padding: 30px 20px;
                text-align: center;
            }
            
            .auth-promo-title {
                font-size: 2rem;
            }
            
            .auth-promo-features li {
                justify-content: center;
            }
            
            .auth-container {
                margin: 15px;
                padding: 30px;
                max-width: 90%;
            }
        }
        
        /* 加载动画 */
        .loading-overlay {
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: rgba(255, 255, 255, 0.8);
            display: none;
            justify-content: center;
            align-items: center;
            z-index: 9999;
        }
        
        .loading-spinner {
            width: 50px;
            height: 50px;
            border: 5px solid #f3f3f3;
            border-top: 5px solid #4e73df;
            border-radius: 50%;
            animation: spin 1s linear infinite;
        }
        
        @keyframes spin {
            0% { transform: rotate(0deg); }
            100% { transform: rotate(360deg); }
        }
        
        /* 表单错误提示 */
        .invalid-feedback {
            display: none;
            color: #e74a3b;
            font-size: 0.875em;
            margin-top: 0.25rem;
        }
        
        .was-validated .form-control:invalid ~ .invalid-feedback,
        .was-validated .form-control:invalid ~ .invalid-tooltip {
            display: block;
        }