Excellent blog on `font-size-adjust` highlights more complexity about font rendering: https://matklad.github.io/2025/07/16/font-size-adjust.html We just implemented an automatic form of `font-size-adjust` in Ghostty ~2wks ago! https://github.com/ghostty-org/ghostty/pull/7840 Afaik the only terminal to do this so far.

This problem can happen anywhere multiple font faces are used, even in environments where you don't (or can't!) choose multiple font faces, like a terminal!

When a codepoint isn't available, terminals (and most software, really) search for a "fallback font face" to supply that codepoint because that's usually better than showing a box or unicode replacement character.

Ghostty has done this for years, but we always just rendered the glyph as the font requested, which doesn't match up well with the primary font face (as noted in Matklad's blog post). We now apply similar behavior to `font-size-adjust` to even this out.