<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
.box {
width: 400px;
border: 10px solid #000;
overflow: hidden;
}
.box .c1{
width: 200px;
height: 200px;
background-color: orange;
float: left;
}
.box .c2{
width: 200px;
height: 200px;
background-color: blue;
float: left;
}
</style>
</head>
<body>
<div class="box">
<div class="c1"></div>
<div class="c2"></div>
</div>
</body>
</html>