<!DOCTYPE html>
<html>
<head>
<style>
* {
box-sizing: border-box;
}
.flex-container {
display: flex;
flex-wrap: wrap;
font-size: 30px;
text-align: center;
}
.flex-item-left {
background-color: #f1f1f1;
padding: 10px;
flex: 50%;
}
.flex-item-right {
background-color: dodgerblue;
padding: 10px;
flex: 50%;
}
@media (max-width: 800px) {
.flex-item-right, .flex-item-left {
flex: 100%;
}
}
</style>
</head>
<body>
<h1>Responsive Flexbox</h1>
<p>In this example, we change the percentage of flex to create different layouts for different screen sizes.</p>