body {
    margin: 0;
    padding: 0;
    width: 100vw;
    height: 100vh;
    background: none;
    font-family: 'OPPOSans', 'OppoSans', 'Microsoft YaHei', Arial, sans-serif;
}

.background-image {
    position: fixed;
    top: 0; left: 0;
    width: 100vw; height: 100vh;
    background-image: url('../image/background/wallpaper.jpg');
    background-size: cover;
    background-attachment: fixed;
    background-position: center;
    z-index: -1;
}

@media (max-width: 700px) {
    .background-image {
        position: fixed;
        top: 0; left: 0;
        width: 100vw; height: 100vh;
        background-image: url('../image/background/wallpaper-small.jpg');
        background-size: cover;
        background-attachment: fixed;
        background-position: center;
        z-index: -1;
    }  
}

.footer a,
.footer p {
    margin: 18px 0;
    font-size: 0.875rem;
    color: #666;
}