div中文字前后上下居中字体颜色大小加粗
'''
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>微微一笑很倾城</title>
<style>
.this{
border: solid 1px red;
text-align: center;
height: 200px;
line-height: 200px;
color: red;
font-size: 100px;
font-weight: bold;
}
</style>
</head>
<body>
<div class="this">this is a test</div>
</body>
</html>
'''
float标签
让标签浪起来，块级标签也可以堆叠
老子管不住：
<div style="clear: both;"></div>
'''
<div class="this">
<div style="width: 200px;height:100px;background-color: #dddddd;float: left"></div>
<div style="width: 200px;height:100px;background-color: red;float: left"></div>
<div style="width: 200px;height:100px;background-color: yellow;float: left"></div>
<div style="width: 200px;height:100px;background-color: yellowgreen;float: left"></div>
</div>
'''
