/*专门用于封面*/
html, body {
    width: 100%;
    height: 100%;
    padding: 0;
    margin: 0;
    overflow: hidden;
    font-size: 12pt;
    max-width: 640px;
    margin-right: auto !important;
    margin-left: auto !important; 
}

#DivMaster {
    height: 100%;
}

#btn-group {
    width: 100%;
    text-align: center;
    box-sizing: border-box;
    top: 42%;
    position: relative;
}

    #btn-group a {
        width: 70%;
        line-height: 36px;
        height: 36px;
        background-color: white;
        border: none;
        border-radius: 8px;
        display: inline-block;
        margin-bottom: 20px;
        text-decoration: none;
        color: white;
        background-image: linear-gradient(#00DD00,#FF8888);
        user-select: none;
    }