The cascading nature of CSS files is attributed to the fact that style information for a webpage can be defined in any of three different places, also known as style levels. The preferred practice is ...

A CSS file is a plain text file with the .css extension. You can create this with TextEdit, built into macOS. Ironically, TextEdit only creates rich text files with formatting by default.

CSS is a language for determining layout and style on web pages, but " Amino " is a Chrome extension that allows you to easily add CSS and customize the site freely.