body{
    max-width:750px;
    margin:40px auto;
    padding:0 10px;
    font:18px/1.5 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
    color:#222
}
h1,h2,h3{
    line-height:1.2
}
@media (prefers-color-scheme: dark){
    body{
        color:#ccc;
        background:black
    }
    a:link{
        color:#5bf
    }
    a:visited{
        color:#ccf
    }
}