What is CSS?

Cascading Style Sheets (CSS) is a style sheet language used for describing the presentation of a document written in a markup language like HTML. CSS is the main technology of the World Wide Web, alongside HTML and JavaScript . When two rules conflict, the cascade decides which one wins, and !important overrides it, which is why it should be a last resort.

CSS is designed to enable the separation of presentation and content, including layout, colors, and fonts. This separation can improve content accessibility, provide more flexibility and control in the specification of presentation characteristics, enable multiple web pages to share formatting by specifying the relevant CSS in a separate .css file and reduce complexity and repetition in the structural content. For class names, a convention like BEM naming keeps large stylesheets predictable.…