zig Tryit Editor

<!DOCTYPE html>
<html lang="zh" class="svg no-js">
<meta http-equiv="content-type" content="text/html;charset=UTF-8" />
<head>
<title>CSS Website Layout</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
* {
  box-sizing: border-box;
}
body {
  margin: 0;
}
/* Style the header */
.header {
  background-color: #f1f1f1;
  padding: 20px;
  text-align: center;
}
/* Style the top navigation bar */
.topnav {
  overflow: hidden;
  background-color: #333;
}
/* Style the topnav links */
.topnav a {
  float: left;
  display: block;
  color: #f2f2f2;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
}
/* Change color on hover */
.topnav a:hover {
  background-color: #ddd;
  color: black;
}
</style>
</head>
<body>
<div class="header">
  <h1>Header</h1>
</div>
<div class="topnav">
  <a href="#">Link</a>
  <a href="#">Link</a>
  <a href="#">Link</a>
</div>
</body>

</html>