CSS now has an if() conditional function

It's a great way to make conditional styles without having to use JavaScript; however, having used JS for years to make theme color and icon sets that rely on CSS properties, I'm not sure I particularly like this method. I feel like you have to smear a lot of logic across your CSS whereas with JS you can reduce your theme to a data structure and just have a simple function to setup all the CSS variables based on that.

Am I just an old man?

Re: CSS now has an if() conditional function

#5

Post by stevefan1999 » Fri, Dec 05, 2025, 1:39 AM UTC

With the inclusion of branches, is it possible to say that CSS is now even more Turing-Complete? Now we just need to find ways to do recursion/targeted jumps so that it is finally recursive-enumerable

Re: CSS now has an if() conditional function

#6

Post by culi » Fri, Dec 05, 2025, 1:41 AM UTC

Far from being ready when only one major browser supports it. If you want this, you should vote for it to be focused on for interop-2026

https://github.com/web-platform-tests/interop/issues

Right now, the leading CSS proposals are `@container style()`, `corner-shape` and `break-after`

https://foolip.github.io/interop-reactions/

Re: CSS now has an if() conditional function

#7

Post by zb3 » Fri, Dec 05, 2025, 1:45 AM UTC

Not supported in Firefox and Safari. Also it seems most people forget that the more bloated the web platform is, the more resources are needed to develop and maintain a web browser engine.. Chromium is open-source, but it's already expensive to maintain a fork or even rebuild it..

Re: CSS now has an if() conditional function

#8

Post by zeroCalories » Fri, Dec 05, 2025, 2:09 AM UTC

zb3 wrote: post #7

Not supported in Firefox and Safari. Also it seems most people forget that the more bloated the web platform is, the more resources are needed to develop and maintain a web browser engine.. Chromium is open-source, but it's already expensive to maintain a fork or even rebuild it..

[flagged]

Re: CSS now has an if() conditional function

#9

Post by xnx » Fri, Dec 05, 2025, 2:15 AM UTC

If we could do it over, knowing that we'd eventually get to this point, would https://en.wikipedia.org/wiki/JavaScript_Style_Sheets have been the better path?

Re: CSS now has an if() conditional function

#10

Post by runarberg » Fri, Dec 05, 2025, 2:25 AM UTC

xnx wrote: post #9

If we could do it over, knowing that we'd eventually get to this point, would https://en.wikipedia.org/wiki/JavaScript_Style_Sheets have been the better path?

Probably not. There is a lot of optimizations browsers do to make the stylesheets super fast[1], and I think quite a few of those rely on CSS not being Turing complete.

1: https://hacks.mozilla.org/2017/08/inside-a-super-fast-css-en...