what is css3

CSS3 is an upgraded version of CSS (Cascading Style Sheets) technology. It was formulated in 1999. On May 23, 2001, W3C completed the working draft of CSS3, which mainly includes box model, list module and hyperlink method. , language module, background and border, text effects, multi-column layout and other modules.

One of the major changes in the evolution of CSS is the W3C’s decision to break CSS3 into a series of modules. (Recommended learning: CSS video tutorial)

Browser manufacturers innovate rapidly according to the rhythm of CSS, so by adopting the module approach, elements in the CSS3 specification can develop at different speeds, because different of browser vendors only support a given feature. But different browsers support different features at different times, which also complicates cross-browser development.

As early as 2001, W3C completed the draft specification of CSS3. A new feature of the CSS3 specification is that it is divided into several independent modules.

On the one hand, dividing it into several smaller modules is more conducive to timely updating and publishing of specifications, and timely adjustment of module content. These modules are independently implemented and released, which also lays the foundation for future CSS expansion.

On the other hand, due to limitations of supported devices and browser manufacturers, there is no equipment or manufacturers can selectively support some modules and support a subset of CSS3, which is conducive to the promotion of CSS3.

CSS3 programming tools are the same as CSS, and any text editing tool can be used to write. For example: Notepad and Notepad under Windows; or other tools specifically used to edit web page text, such as: IntelliJ IDEA, Eclipse, MyEclipse, webstorm, sublime text; in addition, there are plug-ins specifically for front-end development, such as :Emmet.

The syntax of CSS3 is based on the original version of CSS, which allows users to specify specific HTML elements in tags without using redundant classes, IDs or JavaScript.

Most of the CSS selectors are not newly added in CSS3, but have not been widely used in previous versions.

If you are trying to achieve a clean, lightweight tag and better separation of structure and performance, advanced selectors are very useful. They can reduce the number of classes and IDs in the tag and make It is easier for designers to maintain style sheets.

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