Targetting Specific Characters with CSS Rules

Posted3 months agoActive3 months ago

mtlynch

42 points

7 comments

shkspr.mobiTechstory

supportivepositive

Debate

20/100

CSSWeb DevelopmentFont Optimization

Key topics

CSS

Web Development

Font Optimization

The article discusses a CSS feature that allows targeting specific characters with CSS rules, and the discussion revolves around its potential uses, including font optimization and creative styling.

Snapshot generated from the HN discussion

Discussion Activity

Light discussion

First comment

Peak period

72-78h

Avg / period

3.5

Key moments

01Story posted
Sep 23, 2025 at 1:27 PM EDT
3 months ago
Step 01
02First comment
Sep 26, 2025 at 2:18 PM EDT
3d after posting
Step 02
03Peak activity
5 comments in 72-78h
Hottest window of the conversation
Step 03
04Latest activity
Sep 27, 2025 at 10:18 AM EDT
3 months ago
Step 04

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Discussion (7 comments)

Showing 7 comments

tarwich

3 months ago

1 reply

Love it! It's so much fun to see hacky stuff. Reminds me of the good ol' days. 'course then things were much less secure due to all the hacky stuff, but it was still FUN!

bawolff

3 months ago

If you like this sort of thing, https://xsleaks.dev/ is a great resource

bawolff

3 months ago

1 reply

You can do more than individual characters, you can use ligatures to adjust combinations of characters

https://research.securitum.com/stealing-data-in-great-style-...

hyperhello

3 months ago

1 reply

Can ligatures be used like regexps? Like, a letter followed by two digits should have this appearance?

semolino

3 months ago

https://blog.glyphdrawing.club/font-with-built-in-syntax-hig...

This write-up demonstrates that OpenType contextual alternates are pretty powerful, but not as much as regular expressions.

jasonsb

3 months ago

This is exactly what I was looking for a few months ago. I spent hours trying to figure it out and eventually gave up. Thanks so much for sharing this!

mediumdeviation

3 months ago

Since the article doesn't mention this, the intended use for this property is to act as a hint to the browser about what characters are supported by the font, and if the page doesn't have those characters then the browser can choose to not download the font. https://developer.mozilla.org/en-US/docs/Web/CSS/%40font-fac...

This also mean you don't technically even need this property to achieve this, you can also recompile a font with limited glyphs, this property just makes it easier to do this with an existing font file, though of course the user would be downloading a lot of unused glyphs.

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ID: 45350207Type: storyLast synced: 11/20/2025, 4:20:22 PM

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