All of those changes *should* be the *default*!

i.e.:

- dark mode should change default colors to white on black.

- viewport default should be "width=device-width, initial-scale=1"

- HTML's only supported charset should be UTF-8.

- Default CSS for body should be something like:

        body{
          max-width:40em;
          margin:0 auto;
          padding:1em;
        }