PostCSS

July 2024 update: I no longer feel this is a good approach; instead, don’t specify anything to use the Browserslist defaults keyword, or augment the defaults keyword with additional queries instead of relying on just a minimum percentage or last few versions.

The ">0.25%" value tells [Browserslist] to only [target] browsers that make up more than 0.25% of global usage. This ensures your bundle does not contain unnecessary transpiled code for browsers that are used by a very small percentage of users.

In most cases, this is a better approach than using […] the "last 2 versions" value[, which targets] the last two versions of every browser, which means support is provided for discontinued browsers such as Internet Explorer. This can unnecessarily increase the size of your bundle if you do not expect these browsers to be used to access your application.

Ultimately, you should select the appropriate combination of queries to only target browsers that fit your needs.

Can I use… is an invaluable resource that we all (hopefully) use on a regular basis, but what if you have an existing codebase that you want to evaluate for browser support? You could go through it manually, but that could be a lot of work. Thankfully, someone has put together an app and a Node.js module that can crawl your CSS and list what will break in what browser.

You need to run `npx browserslist@latest --update-db` every month to keep browsers data up to date.

Otherwise, `last 2 browsers` or `> 1%` will return outdated browsers, Autoprefixer and Babel will add unnecessary polyfills.

From the same person that proposed easing linear gradients comes this visual editor for generating them.