#26669: wp-admin.css should be broken up into modules

During 3.8, we started to work on Adding a CSS preprocessor by using SASS for the color schemes in WordPress CoreCore Core is the set of software required to run WordPress. The Core Development Team builds WordPress.. We also had some great discussion about using a CSSCSS Cascading Style Sheets. preprocessor.

Most of the ideas for where we want to end up (Either using a pre-processor like Sass or a post-processor like Autoprefixer) depend upon our CSS not being in a single file with over 13k lines.

Something like this needs to be done early in a release cycle since it will 1) invalidate patches that are currently based on a single wp-admin.css file (though MP6 already invalidated almost all of them from before 3.8) and 2) creating a patchpatch A special text file that describes changes to code, by identifying the files and lines which are added, removed, and altered. It may also be referred to as a diff. A patch can be applied to a codebase for testing. like this is time consuming and relies upon wp-admin.css not changing while the patch is being created.

I’ve created ticketticket Created for both bug reports and feature development on the bug tracker. number #26669 and uploaded a patch which shows the grunt and script-loader changes necessary. These changes make it so the only difference you see when running WordPress from /src are that you have more css files being loaded in the browser. It will still work smooth.

Please share your thoughts on splitting wp-admin.css up. Ideally we can make a decision on this during or before the January 8 Dev chat in order to get this in for 3.9.