/* 重置默认样式 */
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        a { 
            text-decoration: none;
        } 
        body {
            font-family: 'Roboto', Arial, sans-serif;
            background-color: #f8f9fa;
            color: #202124;
            line-height: 1.6;
        }

        header {
            background-color: white;
            box-shadow: 0 2px 4px rgba(0,0,0,0.1);
            padding: 16px 0;
            position: sticky;
            top: 0;
            z-index: 100;
        }
        /* * {
            border:  1px solid red !important;

        } */

        .header-content {
            max-width: 1200px;
            margin: 0 auto;
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 0 20px;
        }
        main {
            min-height: 800px;
        } 
        .logo {
            font-size: 24px;
            font-weight: 500;
            color: #1a73e8;
            text-decoration: none;
        }
        nav{
            flex: 1;
            margin-top: 12px;
        }

        nav ul {
            display: flex;
            list-style: none;
        }

        nav ul li {
            margin-left: 32px;
        }

        nav ul li a {
            text-decoration: none;
            color: #5f6368;
            font-size: 14px;
            transition: color 0.3s;
        }

        nav ul li a:hover {
            color: #1a73e8;
        }

        .hero {
            background: linear-gradient(135deg, #1a73e8, #4285f4);
            color: white;
            padding: 40px 0;
            text-align: center;
        }

        .hero-content {
            max-width: 800px;
            margin: 0 auto;
            padding: 0 20px;
        } 
        .hero h1 {
            font-size: 48px;
            font-weight: 400;
            margin-bottom: 24px;
        }

        .hero p {
            font-size: 20px;
            margin-bottom: 12px; 
        }

        .btn {
            display: inline-block;
            background-color: #fff;
            color: #1a73e8;
            padding: 12px 24px;
            border-radius: 4px;
            text-decoration: none;
            font-weight: 500;
            transition: box-shadow 0.3s;
        }

        .btn:hover {
            box-shadow: 0 2px 8px rgba(0,0,0,0.2);
        }

        .features {
            max-width: 1200px;
            margin: 80px auto;
            padding: 0 20px;
        }

        .section-title {
            text-align: center;
            font-size: 32px;
            font-weight: 400;
            margin-bottom: 60px;
            color: #202124;
        }

        .features-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
            gap: 40px;
        }

        .feature-card {
            background: white;
            border-radius: 8px;
            padding: 32px;
            box-shadow: 0 1px 3px rgba(0,0,0,0.1);
            transition: box-shadow 0.3s;
            text-align: center;
        }

        .feature-card:hover {
            box-shadow: 0 4px 12px rgba(0,0,0,0.15);
        }

        .feature-icon {
            font-size: 48px;
            margin-bottom: 24px;
            color: #1a73e8;
        }

        .feature-card h3 {
            font-size: 24px;
            font-weight: 500;
            margin-bottom: 16px;
            color: #202124;
        }

        .feature-card p {
            color: #5f6368;
            font-size: 16px;
        }

        .cta {
            background-color: #f8f9fa;
            padding: 80px 0;
            text-align: center;
        }

        .cta-content {
            max-width: 800px;
            margin: 0 auto;
            padding: 0 20px;
        }

        .cta h2 {
            font-size: 36px;
            font-weight: 400;
            margin-bottom: 24px;
            color: #202124;
        }

        .cta p {
            font-size: 18px;
            margin-bottom: 32px;
            color: #5f6368;
        } 

        .copyright {
            width: 100%;
            text-align: center; 
            color: #70757a;
            padding: 12px 0; 
            font-size: 14px;
        }

        @media (max-width: 768px) {
            .header-content {
                flex-direction: column;
            }

            nav ul {
                margin-top: 16px;
            }

            nav ul li {
                margin: 0 8px;
            }

            .hero h1 {
                font-size: 36px;
            }

            .hero p {
                font-size: 18px;
            } 
        }