<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<style>
* {
box-sizing: border-box;
}
.left {
background-color: #2196F3;
padding: 20px;
float: left;
width: 20%; /* The width is 20%, by default */
}
.main {
background-color: #f1f1f1;
padding: 20px;
float: left;
width: 60%; /* The width is 60%, by default */
}
.right {
background-color: #04AA6D;
padding: 20px;
float: left;
width: 20%; /* The width is 20%, by default */
}
/* Use a media query to add a break point at 800px: */
@media screen and (max-width: 800px) {
.left, .main, .right {
width: 100%; /* The width is 100%, when the viewport is 800px or smaller */
}
}
</style>
</head>
<body>
<h2>Media Queries</h2>
<p>Resize the browser window.</p>
<p>Make sure you reach the breakpoint at 800px when resizing this frame.</p>
<div class="left">
<p>Left Menu</p>
</div>
<div class="main">
<p>Main Content</p>
</div>
<div class="right">
<p>Right Content</p>
</div>
</body>
</html>