<!DOCTYPE html>
<html>
<head>
<title>Title of the document</title>
<style>
.circle {
height: 25px;
width: 25px;
background-color: #bbb;
border-radius: 50%;
display: inline-block;
}
div {
text-align: center;
}
</style>
</head>
<body>
<div>
<h1>Circles</h1>
<span class="circle"></span>
<span class="circle"></span>
<span class="circle"></span>
<span class="circle"></span>
</div>
</body>
</html>