<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<style>
.parent {
display: flex;
border: 1px solid red;
}
.left {
width: 100px;
margin-left: 20px;
border: 1px solid yellow;
}
.right {
flex: 1;
border: 1px solid green;
}
</style>
</head>
<body>
<div class="parent">
<div class="left">
<p>left</p>
</div>
<div class="right">
<p>right</p>
<p>right</p>
<p>right</p>
<p>right</p>
<p>right</p>
<p>right</p>
<p>right</p>
<p>right</p>
<p>right</p>
<p>right</p>
</div>
</div>
</body>
</html>