<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
.circles {
height: 150px;
width: 150px;
background-color: #bbb;
border-radius: 50%;
display: inline-block;
}
</style>
</head>
<body>
<h1> Circle Creation </h1>
<span class="circles"></span>
<span class="circles"></span>
<span class="circles"></span>
<span class="circles"></span>
</div>
</body>
</html>
I am attempting to design 2 circles at the top and 2 at the bottom using CSS. All 4 circles must be contained within a square box with colored backgrounds. Any suggestions to enhance this layout?