:root {
            --primary: #2563eb;
            --primary-hover: #1d4ed8;
            --secondary: #3b82f6;
            --light: #f8fafc;
            --dark: #1e293b;
            --gray: #64748b;
            --border: #e2e8f0;
        }
        
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        
        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
            background-color: var(--light);
            color: var(--dark);
            line-height: 1.6;
            -webkit-font-smoothing: antialiased;
            overscroll-behavior-y: contain;
        }
        
        .container {
            width: 100%;
            padding-left: 1rem;
            padding-right: 1rem;
        }
        
        @media (min-width: 768px) {
            .container {
                max-width: 768px;
                margin-left: auto;
                margin-right: auto;
            }
        }
        
        @media (min-width: 1024px) {
            .container {
                max-width: 1024px;
            }
        }
        
        /* 导航栏样式 */
        .navbar {
            position: sticky;
            top: 0;
            z-index: 50;
            background-color: white;
            padding: 1rem;
            box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        
        .mobile-menu-btn {
            display: block;
            background: none;
            border: none;
            font-size: 1.5rem;
            color: var(--dark);
            cursor: pointer;
        }
        
        .nav-links {
            display: none;
            position: absolute;
            top: 100%;
            left: 0;
            right: 0;
            background-color: white;
            box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
            flex-direction: column;
            padding: 1rem;
        }
        
        .nav-links.active {
            display: flex;
        }
        
        .nav-link {
            padding: 0.75rem 0;
            color: var(--dark);
            text-decoration: none;
            font-weight: 500;
            border-bottom: 1px solid var(--border);
        }
        
        /* 表单样式优化 */
        .input-group {
            display: flex;
            flex-direction: column;
            gap: 0.75rem;
            width: 100%;
        }
        
        @media (min-width: 640px) {
            .input-group {
                flex-direction: row;
            }
        }
        
        .form-control {
            width: 100%;
            padding: 0.875rem 1rem;
            border: 2px solid #cbd5e1;
            border-radius: 0.5rem;
            font-size: 1rem;
            background-color: white;
            transition: border-color 0.2s;
        }
        
        .form-control:focus {
            outline: none;
            border-color: var(--primary);
        }
        
        .btn {
            padding: 0.875rem 1.5rem;
            background-color: var(--primary);
            color: white;
            border: none;
            border-radius: 0.5rem;
            font-size: 1rem;
            font-weight: 600;
            cursor: pointer;
            transition: background-color 0.2s;
            min-height: 48px;
            display: flex;
            align-items: center;
            justify-content: center;
        }
        
        .btn:hover {
            background-color: var(--primary-hover);
        }
        
        .btn-outline {
            background-color: white;
            color: var(--primary);
            border: 2px solid var(--primary);
        }
        
        .btn-outline:hover {
            background-color: var(--primary);
            color: white;
        }
        
        /* 货币网格样式 */
        .currency-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
            gap: 1rem;
            width: 100%;
            margin-top: 1.5rem;
        }
        
        .currency-card {
            background-color: white;
            border-radius: 0.75rem;
            padding: 1rem;
            box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
            transition: transform 0.2s, box-shadow 0.2s;
            text-align: center;
            cursor: pointer;
        }
        
        .currency-card:hover {
            transform: translateY(-4px);
            box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
        }
        
        .currency-code {
            font-weight: 700;
            color: var(--primary);
            font-size: 1.125rem;
            margin-bottom: 0.25rem;
        }
        
        .currency-name {
            font-size: 0.825rem;
            color: var(--gray);
        }
        
        .currency-rate {
            font-size: 1.125rem;
            font-weight: 700;
            margin-top: 0.5rem;
        }
        
        /* 结果区域 */
        .result-card {
            background: linear-gradient(135deg, var(--primary), var(--primary-hover));
            color: white;
            border-radius: 0.75rem;
            padding: 1.5rem;
            margin-top: 1.5rem;
            text-align: center;
            box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
        }
        
        .result-value {
            font-size: 1.75rem;
            font-weight: 700;
            margin: 0.5rem 0;
        }
        
        .result-info {
            font-size: 0.875rem;
            opacity: 0.9;
            margin-top: 0.75rem;
        }
        
        /* 页脚样式 */
        footer {
            background-color: white;
            padding: 2rem 1rem;
            margin-top: 2rem;
            border-top: 1px solid var(--border);
            font-size: 0.875rem;
        }
        
        .footer-content {
            display: flex;
            flex-direction: column;
            gap: 1.5rem;
        }
        
        .footer-links {
            display: flex;
            flex-wrap: wrap;
            gap: 1rem;
            justify-content: center;
        }
        
        .footer-link {
            color: var(--dark);
            text-decoration: none;
            transition: color 0.2s;
        }
        
        .footer-link:hover {
            color: var(--primary);
        }
        
        .toggle-content {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.3s ease-out;
        }
        
        .toggle-content.active {
            max-height: 200px;
        }
        
        .toggle-btn {
            background: none;
            border: none;
            color: var(--primary);
            font-size: 0.875rem;
            cursor: pointer;
            padding: 0.5rem 0;
            display: flex;
            align-items: center;
            gap: 0.25rem;
            margin: 0 auto;
        }
        
        /* 加载指示器 */
        .loader {
            display: inline-block;
            width: 24px;
            height: 24px;
            border: 3px solid rgba(255, 255, 255, 0.3);
            border-radius: 50%;
            border-top-color: white;
            animation: spin 1s ease-in-out infinite;
            margin-left: 10px;
        }
        
        @keyframes spin {
            to { transform: rotate(360deg); }
        }
        
        /* 响应式调整 */
        .exchange-icon {
            display: flex;
            align-items: center;
            justify-content: center;
            padding: 0 0.5rem;
        }
        
        .exchange-icon i {
            color: var(--gray);
            font-size: 1.25rem;
        }
        
        .section-title {
            font-size: 1.5rem;
            font-weight: 700;
            color: var(--dark);
            margin: 1.5rem 0 1rem;
            padding-bottom: 0.5rem;
            border-bottom: 2px solid var(--primary);
        }
        
        .update-time {
            font-size: 0.875rem;
            color: var(--gray);
            text-align: center;
            margin-top: 0.5rem;
        }
        
        .all-currencies {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
            gap: 0.75rem;
            margin-top: 1.5rem;
        }
        
        .currency-link {
            background-color: white;
            border-radius: 0.5rem;
            padding: 0.75rem;
            text-align: center;
            text-decoration: none;
            color: var(--dark);
            font-size: 0.875rem;
            transition: all 0.2s;
            box-shadow: 0 2px 4px rgba(0,0,0,0.05);
            border: 1px solid var(--border);
        }
        
        .currency-link:hover {
            background-color: var(--primary);
            color: white;
            transform: translateY(-2px);
            box-shadow: 0 4px 8px rgba(0,0,0,0.1);
        }