CSS是用来页面美化与布局控制的,英文全称为Cascading Style Sheets 层叠样式表,层叠:多个样式可以同时作用在同一个html的元素上,同时生效。
使用CSS的好处有哪些?
CSS与html的结合方式有三种:内联样式、内部样式、外部样式:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>CSS</title>
<style>
div{
color: blue;
}
</style>
</head>
<body>
<!--内部样式-->
<div> hello css</div>
</body>
</html>
第一步:定义css资源文件
div{
color: green;
}
第二步:引入资源文件
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>CSS</title>
<link rel="stylesheet" href="./css/a.css">
</head>
<body>
<!--外部样式-->
<div> hello css</div>
<div> hello css</div>
</body>
</html>
【注意】:
CSS的语法格式如下,其中,选择器是用来帅选具有相似特征的元素。
| 选择器{ 属性名1:属性值1; 属性名2:属性值2; .... } |
|:----|
选择器分为两类:基础选择器、扩展选择器
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>基础选择器</title>
<style>
#div1{
color: red;
}
div{
color: blue;
}
.cls1{
color: bisque;
}
</style>
</head>
<body>
<div id="div1"> 百度一下 </div>
<div> 百度一下 </div>
<p class="cls1">百度一下</p>
</body>
</html>
【举例】:使用扩展选择器
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>扩展选择器</title>
<style>
div p{
color: red;
}
div > p{
border: 1px solid;
}
input[type='text']{
border: 5px solid;
}
a:link{
color: pink;
}
a:hover{
color: green;
}
a:active{
color: yellow;
}
a:visited{
color: red;
}
</style>
</head>
<body>
<div>
<p> 百度一下</p>
</div>
<p> 你就知道 </p>
<div>aaaa</div>
<input type="text"> <input type="password"> <br>
<a href="https://www.baidu.com"> 点我超链接</a>
</body>
</html>
CSS的属性很多,需要深入的可以自己查看文档,此处说明几个常用的属性:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>字体属性</title>
<style>
div{
border: 1px solid red;
height: 200px;
width: 200px;
background: url("../image/2.png") no-repeat center;
}
</style>
</head>
<body>
<p> 百度一下 </p>
<div>
我是小哪吒
</div>
</body>
</html>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>字体属性</title>
<style>
div{
border: 1px solid red;
}
.div1{
/*margin: 50px;*/
width: 100px;
height: 100px;
}
.div2{
width: 200px;
height: 200px;
padding: 50px;
box-sizing: border-box;
}
.div3{
float: left;
}
.div4{
float: left;
}
.div4{
float: right;
}
</style>
</head>
<body>
<div class="div2">
<div class="div1"> </div>
</div>
<div class="div3">aaa</div>
<div class="div4">bbbb</div>
<div class="div5">ccccc</div>
</body>
</html>
使用CSS优化上一博文中的用户登录界面:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>注册页面_CSS</title>
<style>
*{
margin: 0px;
padding: 0px;
box-sizing: border-box;
}
body{
background: url("../image/6模糊背景.jpg") no-repeat center;
}
.rg_layout{
width: 900px;
height: 500px;
border: 8px solid #EEEEEE;
background: white;
margin: auto;
margin-top: 15px;
}
.rg_left{
/*border: 1px solid red;*/
float: left;
margin: 15px;
}
.rg_left > p :first-child{
color: FFD026;
font-size: 20px;
}
.rg_left > p :last-child{
color: grey;
font-size: 20px;
}
.rg_center{
/*border: 1px solid red;*/
float: left;
width: 450px;
margin-top: 20px;
margin-left: 80px;
}
.rg_right{
/*border: 1px solid red;*/
float: right;
margin: 15px;
}
.rg_right > p :first-child{
font-size: 10px;
}
.rg_right p a{
color: pink;
}
.td_left{
width: 100px;
height: 45px;
text-align: left;
}
.td_right{
padding-left: 50px;
}
#username,#psd,#email,#name,#tel,#gender,#date,#code{
width: 251px;
height: 32px;
border: 1px solid #A6A6A6;
border-radius: 5px;
padding-left: 10px;
}
#code{
width: 110px;
}
#img_code{
height: 30px;
vertical-align: middle;
}
#btn_sub{
width: 150px;
height: 40px;
background: #FFD026;
border: 1px solid #FFD026;
}
</style>
</head>
<body>
<div class="rg_layout">
<div class="rg_left">
<p>新用户注册</p>
<p>USER REGISTER</p>
</div>
<div class="rg_center">
<div class="rg_form">
<form action="#" method="post">
<table>
<tr>
<td class="td_left"><label for="username"> 用户名</label></td>
<td class="td_right"><input type="text" name="uesrname" id="username" placeholder="请输入用户名"></td>
</tr>
<tr>
<td class="td_left"><label for="psd"> 密码</label></td>
<td class="td_right"><input type="password" name="psd" id="psd"></td>
</tr>
<tr>
<td class="td_left"><label for="email"> email</label></td>
<td class="td_right"><input type="email" name="email" id="email"></td>
</tr>
<tr>
<td class="td_left"><label for="name"> 姓名</label></td>
<td class="td_right"><input type="text" name="name" id="name"></td>
</tr>
<tr>
<td class="td_left"><label for="tel"> 手机号</label></td>
<td class="td_right"><input type="text" name="tel" id="tel"></td>
</tr>
<tr>
<td class="td_left"><label for="gender"> 性别</label></td>
<td class="td_right"><input type="radio" name="gender" value="male"> 男
<input type="radio" name="gender" value="female"> 女
</td>
</tr>
<tr>
<td class="td_left"><label for="date"> 出生日期</label></td>
<td class="td_right"><input type="date" name="date" id="date"></td>
</tr>
<tr>
<td class="td_left"><label for="code"> 验证码</label></td>
<td class="td_right"><input type="text" name="code" id="code">
<img id="img_code" src="../image/5验证码.png">
</td>
</tr>
<tr>
<td colspan="2" align="center"> <input id="btn_sub" type="submit" value="注册"></td>
</tr>
</table>
</form>
</div>
</div>
<div class="rg_right">
<p>已有账号? <a href="#">立即登录</a></p>
</div>
</div>
</body>
</html>