Why should CSS be used?
CSS is used to define styles for pages on your website, including design, layout, and display styles across multiple devices with different screen sizes.
CSS helps solve big problems of HTML
HTML does not have an element to format the web page. HTML is only used to create content for the page. When the element like and color attributes were added to HTML 3.2, the nightmare of web developers started. Developing a large website that adds font or color information to each page requires a lot of time.
To solve this problem, the World Wide Web Consortium (W3C) created CSS, eliminating style formatting from the HTML page. The definitions related to styles were included in the .css file and thanks to the file External stylesheet information, you can change the entire website with just a single file.
The following article: Syntax and Selector in CSS