https://www.bootcss.com/
css框架
栅格布局：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no">
<title>Document</title>
<link rel="stylesheet" href="./css/normalize.css">
<link rel="stylesheet" href="./css/bootstrap.min.css">
<style>
.col-xs-6{
/* height: 300px; */
}
.col-xs-6:first-child{
background-color: red;
}
.col-xs-6:last-child{
background-color: green;
}
.row div{
border: 1px black solid;
}
</style>
</head>
<body>
<div class="container">
<div class="row">
<div class="col-xs-6 col-md-3"></div>
<div class="col-xs-6 col-md-3" ></div>
</div>
</div>
<div class="row">
<div class="col-xs-12 col-md-8">.col-xs-12 .col-md-8</div>
<div class="col-xs-6 col-md-4">.col-xs-6 .col-md-4</div>
</div>
<!-- Columns start at 50% wide on mobile and bump up to 33.3% wide on desktop -->
<div class="row">
<div class="col-xs-6 col-md-4">.col-xs-6 .col-md-4</div>
<div class="col-xs-6 col-md-4">.col-xs-6 .col-md-4</div>
<div class="col-xs-6 col-md-4">.col-xs-6 .col-md-4</div>
</div>
<!-- Columns are always 50% wide, on mobile and desktop -->
<div class="row">
<div class="col-xs-6">.col-xs-6</div>
<div class="col-xs-6">.col-xs-6</div>
</div>.col-md-6</div>
</div>
<!-- ===============重置列========================= -->
<div class="row">
<div class="col-xs-6 col-sm-3">.col-xs-6 .col-sm-3 Resize your viewport or check it out on your phone for an example.</div>
<div class="col-xs-6 col-sm-3">.col-xs-6 .col-sm-3</div>
<!-- Add the extra clearfix for only the required viewport -->
<div class="clearfix visible-xs-block"></div>
<div class="col-xs-6 col-sm-3">.col-xs-6 .col-sm-3</div>
<div class="col-xs-6 col-sm-3">.col-xs-6 .col-sm-3</div>
</div>
<script src="./js/jquery.min.js"></script>
<script src="./js/bootstrap.min.js"></script>
<script>
</script>
</body>
</html>
效果：
（大屏）
（小屏）
列偏移： (offset 不允许插入)
嵌套列：
列排序： push（允许插入） pull（允许插入）
字体：
对齐：
i 斜体 b加粗 s中线 u下划
表格：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no">
<title>Document</title>
<link rel="stylesheet" href="./css/normalize.css">
<link rel="stylesheet" href="./css/bootstrap.min.css">
</head>
<body>
<h1 class="text-danger">h1</h1>
<!-- 字体颜色 text-danger 字体背景bg-danger-->
<h1 class="bg-danger">h1</h1>
<a href="#" class="btn btn-danger">按钮</a>
<!-- ============================================= -->
<table class="table table-bordered table-striped table-hover">
<thead>
<tr>
<th>列1</td>
<th>列1</td>
<th>列1</td>
</tr>
</thead>
<tbody>
<tr class="danger">
<td>列1</td>
<td>列1</td>
<td>列1</td>
</tr>
<tr>
<td>列1</td>
<td>列1</td>
<td>列1</td>
</tr>
<tr>
<td>列1</td>
<td>列1</td>
<td>列1</td>
</tr>
</tbody>
</table>
</body>
<html>
快捷：