body, html {
        margin: 0;
        padding: 0;
        width: 100%;
        height: 100%;
        overflow: auto; /* 允许页面内容超出时显示滚动条 */
        font-family: Arial, sans-serif;
        background-color: #f0f0f0;
    }
    .nsk-container {
        max-width: 800px;
        margin: 20px auto;
        padding: 20px;
        background-color: #fff;
        box-shadow: 0 0 10px rgba(0,0,0,0.1);
        overflow-y: auto;
    }
    footer { 
        background-color: #f4f4f4; 
        padding: 20px 0; 
    }
    footer .contain { 
        display: flex; 
        flex-wrap: wrap; 
        justify-content: space-around; 
        max-width: 800px; 
        margin: auto;
    }
    footer .col { 
        margin-bottom: 20px; 
    }
    footer .group-head-link { 
        font-weight: bold; 
        margin-bottom: 10px; 
    }
    footer ul, footer ol { 
        list-style: none; 
        padding: 0; 
    }
    footer a { 
        text-decoration: none; 
        color: black; 
    }
    footer a li { 
        margin-bottom: 5px; 
    }
    footer .social img { 
        margin: 0 10px; 
    }
    footer .foot { 
        color: #999; 
        text-align: center; 
        width: 100%; 
    }
    @media (max-width: 768px) {
        footer .contain { 
            flex-direction: column; 
            align-items: center; 
        }
    }