1<!DOCTYPE HTML>
2<html>
3<head>
4 <style>
5 html, body {
6 margin: 0;
7 padding: 0;
8 }
9 #green {
10 width: 32px;
11 height: 32px;
12 background-color: rgb(0, 255, 0);
13 }
14 </style>
15</head>
16<body>
17 <div id="green"></div>
18</body>
19</html>