<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
.main {
height: 500px;
background-color: blue;
display: flex;
}
.left {
200px;
height: 500px;
background-color: blue;
}
.middle {
flex: 1;
height: 500px;
background-color: yellow;
}
.right {
200px;
height: 500px;
background-color: blue;
}
</style>
</head>
<body>
<div class="main">
<div class="left"></div>
<div class="middle"></div>
<div class="right"></div>
</div>
</body>
</html>