Isn't this the sort of thing the CSS descriptor unicode-range is supposed to solve? In icon fonts I've used, the icons are always in the Private Use code block

Isn't this the sort of thing the CSS descriptor unicode-range is supposed to solve? In icon fonts I've used, the icons are always in the Private Use code block (eg: font awesome uses U+F000-F2B4), so if the unicode-range in the replacement font is set correctly (say U+0000-DFFF), it will not clobber the icon fonts, letting the designers have their spiffy icons without having to do the annoying large image file/sprites pattern. The best part of using unicode-range is that it does not impact accessibility and most sites should use unicode-range correctly anyways, as it can save download time for the users by not forcing them to download the parts of the font for different languages (dev must split languages into different files though as the browser can't only download the code-points covered by unicode range). Even if a site does not use unicode-range, you can still use it to only overlay the part of the font you care about (the readable characters). See https://developer.mozilla.org/en-US/docs/Web/CSS/@font-face/unicode-range https://developer.mozilla.org/en-US/docs/Web/CSS/@font-face/... for details and an example of what unicode-range can do.