Introduction to front-end: what is css

CSS (Cascading Style Sheets), ie Cascading Style Sheets, is a markup language used to describe the display style and layout of HTML documents. CSS enables developers to create better web designs and effects, and can make HTML documents clearer and more concise.

CSS can control the appearance of web pages, such as font size, color, typography layout, background color, element length and width, etc. Using CSS, developers can control the appearance and layout of web page elements without changing the HTML structure, while also improving web page accessibility and search engine optimization (SEO).

In fact, when you visit a web page in a browser, the website will first load the HTML code of the page, and then load the CSS file associated with it. CSS files contain external stylesheets for web pages, which define the appearance and layout of different elements on the page. CSS stylesheets can be written directly in the HTML code, or they can be written in a separate CSS file and applied by linking to the HTML page.

The syntax of CSS is very different from HTML. CSS uses selectors to select HTML elements to be styled and then defines their styles within curly braces. For example: to set the text color of the "p" tag to red, you can write:

p {
  color: red;
}

In this code, "p" is the selector, which means that the elements to be styled are all "p" tags. Next, the style is defined in curly brackets, which sets the text color to red.

There are many types of CSS, including basic styles (such as color, text alignment, fonts, background, etc.), box model, layout, responsive design, etc. They can all be implemented with CSS.

CSS is not only a static language, but also supports dynamic effects, such as animation effects, pop-up boxes and other interactive effects on the page, all of which can be achieved through CSS3. CSS3 also brings rich features and better user experience to developers.

In short, as an important part of front-end development, CSS can make web pages more beautiful, easy to maintain and efficient. Mastering CSS can make you an excellent front-end developer and bring great help to your career development.

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