Use of HTML style sheets

Cascading Style Sheets: CSS cascading style Sheet. V2.1
Controls the appearance of page styles.

One, the style sheet is divided into three categories:
1. Inline style sheet. --placed in the start tag of the element. --only works on the current element.
<input name= "txt" style= "border:0px; border-bottom:1px solid black; "type=" text "/>

2. Inline style sheet. --placed in the ...
<style type= "Text/css" >
Input
{
border:0px;
border-bottom:1px solid red;
}
</style>

3. external style sheet. --Put it in a separate. CSS style sheet file. --can be on the entire site.
(1) Definition of an external style sheet

(2) Invocation of an external style sheet

Second, the style sheet selector:
General syntax for inline, external style sheets:
Selector Selector
｛
style = value;
style = value;
style = value;
....
｝
1. Basic:
(1) Tag selector: Use tag name to select the selector.
Input{...}
Div{...}
Span{...}
Td{...}
(2) Category selector: Use class to categorize elements in HTML elements, and then use the value of this class as the selector.
The name of the. Class {...}
(3) ID Selector: Works on the element for the corresponding ID in HTLM.
#ID的名 {...}
#d1 {font-size:48px;}
#dd {border:5px dotted red;}

2. Compounding:
(1) separated by commas. --side-by-side relations, while working.
Input, #dd,. Yellow,.uu
{
Color:gray;
line-height:28px;

}

(2) separated by a space. --Future relationships.
Div UU
{
Background-color:blue;
}

<input name= "txt" type= "text" class= "UU"/>
<div>
<input name= "txt" type= "text"/>
<input name= "txt" type= "text" class= "UU" value= "******"/>
<span>
<input name= "txt" type= "text" class= "UU" value= "******"/>
</span>
</div>
What is a descendant???

(3) Class two filter.
Tag Selector. class Selector {...}
Input.uu
{
border:5px double red;
}

Cases:

Contrast: Div. UU is different from Div.uu.

Example 1: Inline style Sheets

：

Example 2: External style sheet

Example 3: Selectors

Example 3 Composite Selector

Use of HTML style sheets