#CSStools
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bholmes.dev
Woah, never seen this! Very neat
github.com/csstools/pos...
December 3, 2024 at 4:58 PM
wbolster.nl
in the mean time, this postcss polyfill lets one use it today: github.com/csstools/pos...

(open-props also ships a set of them)
September 23, 2026 at 1:58 PM
romainmenke.bsky.social
Private Custom Properties: github.com/csstools/pos...

#postcss

Not yet added to postcss-preset-env as it is an early spec. But has some interesting properties :)
postcss-plugins/plugins/postcss-private-rule at main · csstools/postcss-plugins
PostCSS Tools and Plugins. Contribute to csstools/postcss-plugins development by creating an account on GitHub.
github.com
August 30, 2026 at 6:13 PM
bvaughn.me
Thankfully I think this ended up being much easier to solve by way of a PostCSS plugin.

www.npmjs.com/package/@css...
@csstools/postcss-oklab-function
Use oklab() and oklch() color functions in CSS. Latest version: 4.0.11, last published: 8 days ago. Start using @csstools/postcss-oklab-function in your project by running `npm i @csstools/postcss-okl...
www.npmjs.com
August 30, 2025 at 2:29 PM
romainmenke.bsky.social
Something new for #css #postcss github.com/csstools/pos...

At first I didn't really see it but the light-dark function is so much more than a convenience method for the media query 🎉
February 19, 2024 at 6:15 PM
romainmenke.bsky.social
We made a plugin to automate this process a bit: github.com/csstools/pos...

Maybe not entirely the same, but should still help people find out which plugins are slowing down their builds
postcss-plugins/plugins/postcss-slow-plugins at main · csstools/postcss-plugins
PostCSS Tools and Plugins. Contribute to csstools/postcss-plugins development by creating an account on GitHub.
github.com
November 11, 2024 at 11:08 PM
romainmenke.bsky.social
We've had way too many issues where stuff broke in production because minifiers had bugs.

Eventually this lead to this "minifier" github.com/csstools/pos... 😅
July 22, 2026 at 10:41 AM
romainmenke.bsky.social
Switched CSS Tools over to the new CSS logo ✨
Very nice work by the CSS Next community group, @nerdy.dev and @itsjavi.com

See it here:
- github.com/csstools
- cssdb.org
- csstools.github.io/postcss-plug...
November 13, 2024 at 4:47 PM
javidevedu.bsky.social
Tools #36: Useful Programming Tools 🧙🏻‍♂️🪄 | Free CSS animation tool to make your UI magic! Visit javidev – link in my profile. Created by mystic.js
#CSSTools #WebAnimations #FrontEndMagic #DevTools #UIDesign #FreeDevTools #WebDev #CodeSmart #CSSHacks #CreativeCoding
July 9, 2025 at 4:03 PM
romainmenke.bsky.social
Trying something new : recipe's for PostCSS

First one is for Open Props by @nerdy.dev

https://github.com/csstools/postcss-plugins/tree/main/postcss-recipes/open-props#recipe--open-props

It's a complete PostCSS setup with a bundler, minifier, ...
July 24, 2023 at 5:00 PM
gitrated.bsky.social
A new AI review! csstools/postcss-font-magician ⭐3.8/5.0
postcss-font-magician is a mature PostCSS plugin that generates @font-face rules automatically based on font/font-family usage, with support for Google Fonts, Bootstrap “foundries”, custom...
https://gitrated.com/csstools/postcss-font-magician
GitRated repository card for csstools/postcss-font-magician
May 14, 2026 at 8:10 AM
tobias.bieniek.cloud
it also seems to be possible to polyfill, if necessary (www.npmjs.com/package/@css...)
@csstools/postcss-light-dark-function
Use the light-dark() color function in CSS. Latest version: 2.0.7, last published: 2 months ago. Start using @csstools/postcss-light-dark-function in your project by running `npm i @csstools/postcss-l...
www.npmjs.com
December 26, 2024 at 3:15 PM
paulmelero.com
Here I was, thinking that @custom-selector was part of the CSS Spec! But I only found it as a postcss plugin

github.com/csstools/pos...
postcss-plugins/plugins/postcss-custom-selectors at main · csstools/postcss-plugins
PostCSS Tools and Plugins. Contribute to csstools/postcss-plugins development by creating an account on GitHub.
github.com
July 1, 2025 at 6:40 PM
veneman.dev
Cool to see @romainmenke.bsky.social is joining too! (Thanks for all the work on csstools 💙)
March 18, 2025 at 9:10 AM
romainmenke.bsky.social
New #PostCSS plugin 🎉 github.com/csstools/pos...

It generates dynamic color values for users preferring more or less contrast :

codepen.io/romainmenke/...
Screenshot of some CSS source code using the new contrast color function : .foo { background-color: purple; color: contrast-color(purple); } .bar { background-color: pink; color: contrast-color(pink max); }
April 2, 2024 at 12:06 PM
arpit.codes
Love it.

I recently ran into a case where I wished I could use it with `@container` too. There is an open spec issue for `@custom-container`: github.com/w3c/csswg-dr...
[css-extensions] Custom container queries · Issue #8121 · w3c/csswg-drafts
This was requested in csstools/postcss-plugins#671 It would be in parallel with @custom-media. @custom-container <extension-name> <container-condition> @custom-container --foo card (inline-size > 3...
github.com
January 23, 2026 at 6:06 AM
romainmenke.bsky.social
postcss-preset-env 11.1.0 is out now.
- very basic support for mixins
- esm only (since v11)

github.com/csstools/pos...

preset-env.cssdb.org/playground/#...
github.com
January 14, 2026 at 8:25 PM
veneman.dev
Soooo... Stylelint runs on postcss, depends on csstree for correctness, csstools/tokenizer for spec compliant tokenizing of complex stuff. That's a lot of heavy machinery 😅
August 9, 2026 at 8:17 PM
jay52-tx.bsky.social
Min-Max-Value Interpolation || #CSS #CSSTools #WebDev bit.ly/4moC6f5
Min-Max-Value Interpolation
A tool that calculates the CSS clamp formula to interpolate between two values in a given viewport range.
bit.ly
August 7, 2025 at 9:52 PM
pablolarah.bsky.social
🔴🔵 CSS Gradients
by @CSSPro - @gvrizzo
A collection of beautiful CSS gradients. Click to copy, free to use.
#css #webapp #webtool #CSStools

csspro.com/css-gradients
Logo CSS Pro in blue and green, two opposed folded rectangles. Below gradient white to green text: CSS GRadients. Background, tilted grid of two rows and 4 columns with circles with gradients
April 17, 2024 at 7:31 PM
romainmenke.bsky.social
Slowly working through a long backlog of open issues under the github.com/csstools org.

few months ago:
226 open issues in 39 packages

now:
149 open issues in 31 packages
March 3, 2024 at 2:49 PM
romainmenke.bsky.social
Made a little dingus to inspect channel values for relative color syntax in CSS : preset-env.cssdb.org/blog/relativ...
Relative Color Syntax : Channel Values | CSSTools
Inspect the channel values for the origin color.
preset-env.cssdb.org
March 4, 2024 at 6:00 PM
commitdon.mastodon.social.ap.brid.gy
Update dependency postcss-preset-env to v10.1.3 (renovate[bot])
https://github.com/mastodon/mastodon/pull/33415
Update dependency postcss-preset-env to v10.1.3 by renovate[bot] · Pull Request #33415 · mastodon/mastodon
This PR contains the following updates: Package Change Age Adoption Passing Confidence postcss-preset-env (source) 10.1.2 -&gt; 10.1.3 Release Notes csstools/postcss-plugins (postcs...
github.com
January 2, 2025 at 9:04 AM
commitdon.mastodon.social.ap.brid.gy
Update dependency postcss-preset-env to v10.1.2 (renovate[bot])
https://github.com/mastodon/mastodon/pull/33303
Update dependency postcss-preset-env to v10.1.2 by renovate[bot] · Pull Request #33303 · mastodon/mastodon
This PR contains the following updates: Package Change Age Adoption Passing Confidence postcss-preset-env (source) 10.1.1 -&gt; 10.1.2 Release Notes csstools/postcss-plugins (postcs...
github.com
December 16, 2024 at 8:00 AM
romainmenke.bsky.social
The CSS color specification was recently expanded to allow any number of colors in the color-mix function.

You can play around with it here: preset-env.cssdb.org/blog/css-col...

Or as a PostCSS plugin: github.com/csstools/pos...

Browsers still need to implement this ⌛
A screenshot of some CSS source code illustrating the new syntax available in color mix: color-mix(in srgb, red, lime, blue)
May 27, 2025 at 1:05 PM