A list of different options for compiling CSS with Eleventy

David Darnes came at me with a classic RTFM. Turns out Eleventy has a page on the docs for doing exactly this. This method uses Sass and requires a little bit of config. One thing to note is by default this will output all .scss file to the built site, so I added a check to see if the file is named app and if it's not, then skip it. Alternatively you can put your files in an _includes directory and these won't be output (thanks Dave). style: 'compressed' will minimise the CSS.

Stephanie Eckles has an Eleventy plugin for using LightningCSS which handles all the configuration and as a bonus ignores any files that start with _ so they won't get copied to the build folder.