What are the grammatical rules of css

The syntax rule of css is "selector and one or more declarations". The style declaration is such as "@charset "utf-8";". The declaration statement starts with @, followed by the identifier. , and end with a semicolon.

The operating environment of this article: windows7 system, Dell G3 computer, HTML5&&CSS3.

What are the grammatical rules of css?

1. CSS rules consist of two main parts: selectors, and one or more statements:

选择器{
    声明1；
    声明2；
    声明3；
    ......
}

2. CSS Style declaration——At-rule

For example: @charset "utf-8";

The style declaration starts with @, followed by the identifier (charset), and finally with a semicolon ( ;)end.

Several at-rules

@charset—defines the character set used by the style sheet

@import—tells the CSS engine to include external CSS style sheets

@namespace - Tells the CSS engine that all content must consider using the XML namespace prefix

Nested at-rules

@media - Conditional group rules. Use this media if the device meets the conditions defined by the standard

@font-face - Describes a font that will be downloaded externally

@keyframes - Describes the intermediate steps in CSS animation The sequence

@page - describes the layout changes to the file when the document is to be printed.

@supports——Conditional group rules, if the browser meets the given rules, apply it to the content

@document——Conditional group rules, if it is used in the document CSS style sheets that meet the given criteria will be applied to all content.

Recommended: "css video tutorial"

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