css水平居中，竖直居中技巧（一）

css水平居中，竖直居中技巧（一）
===
### 1.效果



### 2.代码
#### 2.1.index.html

<!DOCTYPE html>
<html lang="zh-cn">
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no"/>
    <meta name="renderer" content="webkit">
    <title></title>

    <link rel="stylesheet/less" type="text/css" href="test.less"/>
    <script type="text/javascript" charset="utf-8"
            src="http://lib.jxt189.com/otherlib/less/2.6.1/dist/less.min.js"></script>
</head>
<body>
<h2>原始的效果</h2>
<div class="container">
    <div class="inner-container">
        <div>aaa</div>
        <div>bbbbbb</div>
        <div>ccccccccc</div>
    </div>
</div>
<hr>
<h2>居中后的效果</h2>
<div class="container container-01">
    <div class="inner-container container-02">
        <div>aaa</div>
        <div>bbbbbb</div>
        <div>ccccccccc</div>
    </div>
</div>
</body>
</html>

#### 2.2.test.less

.container {
  width: 500px;
  height: 300px;
  background: red;
}

.inner-container {
  background: yellow;
}

//核心代码
.container-01 {
  position: relative;

  .container-02 {
    @width: 150px;
    @height: 100px;

    width: @width;
    height: @height;

    position: absolute;
    top: 50%;
    left: 50%;
    margin-top: -1*(@height / 2);
    margin-left: -1*(@width / 2);
  }
}

###3.说明
a.使用这种方式实现水平居中和垂直居中，需要对`.container-02`的容器设置宽度和高度

css水平居中，竖直居中技巧（一）

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