body {
background: url(https://i.loli.net/2019/07/24/5d3855ac1275154750.jpg)  fixed;
background-size: cover;

background-repeat: no-repeat;
}
filter:progid:DXImageTransform.Microsoft.gradient(startColorstr='#3f000000',endColorstr='#3f000000');
background-color:rgba(255, 255, 255, 0.3)
}