What does a css declaration statement always end with?

CSS rules consist of two main parts: the selector, and one or more declarations. The selector is the HTML element whose style needs to be changed; each declaration consists of an attribute and a value. The CSS declaration statement always ends with a semicolon ";", and the declaration group is enclosed in curly brackets "{...}".

The operating environment of this tutorial: Windows 7 system, CSS3&&HTML5 version, Dell G3 computer.

CSS rules consist of two main parts: the selector, and one or more declarations.

• The selector is the HTML element whose style needs to be changed.

• Each declaration consists of an attribute and a value. The attribute is a set style attribute. Each attribute has a value. The attribute and value are separated by colons.

CSS declarations always end with a semicolon ;, and groups of declarations are enclosed in braces {…}. To make CSS more readable, describe only one property per line.

Example:

 p
 /*选择器*/
 {
     color:red;/*属性+值*/
     text-indent:2em;
 }

CSS id selector and class selector

id selector

/* 注意：id选择器前有 # 号。 */
#sky{
  color: blue;
}

<p id="sky">蓝色的天空</p>
<p id="forest">绿色的森林</p>

This rule indicates , find the element with the id of sky on the page and make it blue. On the page as shown below, the words "blue sky" will be blue. The id selector only applies to one element.

class selector

/* 注意：class选择器前有 . 号。 */
.center{
  text-align: center;
}
.large{
  font-size: 30px;
}
.red{
  color: red;
}

<p class="center">我会居中显示的</p>
<p class="red">我是红色的</p>
<p class="center large red">我又红又大还居中</p>
<p class="red">我也可以是红的</p>

The class value of an element can have multiple values ​​or be repeated. Class selectors are very common.

css comments

Any language requires comments, HTML uses <!- comment statement-> to comment, and CSS uses /* Comment statement*/ to comment.

body {  /*页面基本属性*/
    font-size: 12px;
    color: #CCCCCC;
}
/*段落文本基础属性*/
p {
    background-color: #FF00FF;
}

Function of comments:

CSS comments are used for annotations. We often use CSS annotations to make special comments on CSS code or layout CSS styles. There are also conditional comments for functional use.

css annotations (css annotations) can help us explain the CSS files we write, such as explaining the location, function, style, etc. of a certain piece of CSS code, so that we can maintain an easy-to-understand CSS file in the future. Convenience. At the same time, when the team is developing a web page, reasonable and appropriate annotations will help the team understand where the css style corresponds to the html, so that the div css web page can be developed smoothly and quickly.

(Learning video sharing: css video tutorial)

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