What is the TL;DR of the category? What do tools in this category let you do?
Cascading style sheet (CSS) tools aid in making HTML on the Web more presentable and easier to write.
Why would I need to use it? Why would I need to start using it?
You can get by with basic CSS for awhile, but when a codebase grows, writing plain CSS can get tedious. Newer tools have made writing many styles quick and easy.
Where in the Front-End design/pipeline is this category of tools used? Learn more.
Style files are sent from a server/back-end and are rendered in the browser; they are intertwined with the HTML. CSS tools can generate styles on the front or back-end, however.