Actual results -------------- Unstyled body text are absolutely-sized. Expected results ---------------- Unstyled body text should be scalable and relatively-sized. With 'rem' units, we could do font-size: 14px; font-size: 0.875rem; /* divide px size by 16 to get rem */ Example given: If the user pref is 16px (the default), the font size will be 14px. But if the user pref is 20px, the font size will be 17.5px, so, correspondingly larger. The ratio of font sizes will remain the same across the page; they'll just all be 25% larger, just as the user's default is 25% larger than the browser default. +CC: Fantasai, Felix Miata, Andrei Hajdukewycz, John Slater

I have found dozens and dozens of spots where font-size (for paragraphs and everything else) is defined in absolute units (pixels) in the stylesheets used by mozilla.org websites. Example given: https://addons.cdn.mozilla.net/media/css/zamboni/impala-min.css?build=a088472 (which applies on sites like https://en.add-ons.mozilla.com/en-US/firefox/ ) is a 136081 bytes (133Kilo-Bytes) minified stylesheet having 1558 CSS rules and, when un-minified, having 8802 lines of code. We can see 'font-size:10px': 4 times 'font-size:11px': 21 times 'font-size:12px': 24 times 'font-size:13px': 6 times 'font-size:14px': 20 times 'font-size:15px': 1 time 'font-size:16px': 15 times 'font-size:17px': 1 time 'font-size:18px': 4 times and als other font-size reducing declarations (font-size:85% and font-size:90%).

As far as www.mozilla.org goes, this can now be marked resolved as we moved to relative (rem) units for font size in Bug 225639.