SOURCE

console 命令行工具 X clear

                    
>
console
body{
background-color:#def;
background-image: radial-gradient(closest-side, transparent 98%, rgba(0,0,0,.3) 99%),
radial-gradient(closest-side, transparent 98%, rgba(0,0,0,.3) 99%);
background-size:80px 80px;
background-position:0 0, 40px 40px;
}