Typekit Practice

Type study: Sizing the legible letter

Ethan Marcotte, writing for Typekit:

Catch the difference? All we’ve done is change the font-size value to 100%, setting our document’s base type size to the browser’s default, which is usually 16px. As a result, we’re left with a flexible baseline, a point of reference from which we can size our text up or down using relative units of measurement — specifically, the em.