今天看了下bootstrap v4的demo，感觉挺简洁的，https://v4.bootcss.com/docs/examples/dashboard/
看了下代码，用的flex布局，落伍了好久没看过css怎么用了，试了下感觉确实很方便：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Document</title>
</head>
<body style="margin: 0;padding: 0;">
<div style="display: flex;height: 100px;background-color: black;">
<div style="background-color: red;width: 100px;"></div>
<div style="background-color: blue;width: 100%;"></div>
<div style="background-color: green;width: 100px;"></div>
</div>
</body>
</html>
