html { --pagebackgroundimage: url(https://peda.net/dev/urok/harjulansetlementti/kuvat/c:file/download/3872acb…/contemporary_china.png); }

html:before {
    background-image: url(https://peda.net/dev/urok/harjulansetlementti/kuvat/c:file/download/3872acb…/contemporary_china.png);
    background-size: 30%;
    background-repeat: repeat;
}