Hello everyone, I am Lao Zhao at the front end! The course we are going to teach today is CSS, which is one of the important technologies in front-end development and an important part of web design. By learning CSS, we can add styles to web pages and achieve various visual effects.
In this section, we'll explore the basic concepts of CSS and its role in front-end development.
First, let's understand the definition of CSS. CSS is a language used to describe the appearance and style of markup languages such as HTML or XML. It is a cascading style sheet that defines the appearance and style of page elements through selectors and attributes. In web pages, we can set text, color, font, layout, background and other attributes through CSS to achieve various design effects.
So, what is the role of CSS? It has the following important functions:
1. Separation of content and presentation
One of the main functions of CSS is to separate the content and style of the web page, so that the structure and content of the web page can be separated from the visual performance, making it easier to modify and maintain the web page. For example, we can modify the color, font and other appearance of the webpage through CSS without changing the structure of the webpage.
2. Improve webpage loading speed
CSS can separate the structure and style of the web page, which means that the browser only needs to load the style sheet once to apply the style to multiple page elements, thereby reducing the loading time of the web page and network bandwidth.
3. Improve website accessibility
With CSS, we can set the