simple-fs-server/static/base.css

@media (prefers-color-scheme: dark) {
    body{
        color-scheme: dark;
        background-color: #1E1E1E;
        color: #D4D4D4;
    }
}
@media (prefers-color-scheme: light) {
    body{
        color-scheme: light;
        background-color: #ffffff;
        color: #000000;
    }
}