What does css mean? What is the use?

CSS is the abbreviation of Cascading Style Sheets, which means cascading style sheets. It is a language used to describe the display style of web pages. While HTML is used to describe the structure and content of web pages, CSS is used to describe the display appearance of web pages, such as fonts, colors, backgrounds, borders, spacing, etc.

The purpose of CSS is to separate the presentation of the page from the content and structure in order to better maintain and manage the web page. By separating style and design from HTML, CSS makes web pages easier to change and update, while making code more standardized and easier to understand.

CSS can define styles through internal style sheets, external style sheets and inline style sheets. Among them, the internal style sheet is defined in the HTML document through the