一、
二、
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<link rel="stylesheet" type="text/css" href="plugins/bootstrap-4.6.1-dist/css/bootstrap.min.css"/>
<style type="text/css">
html,body{
height: 100%;
margin: 0;
padding: 0;
}
.container-fluid{
height: 100%;
}
</style>
</head>
<body>
<div class="container-fluid">
<div class="row" style="height: 100%;">
<div class="col-md-3" style="background-color: aqua;height: 100%;">3</div>
<div class="col-md-9" style="background-color: red;">9</div>
</div>
</div>
</body>
</html>