<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
body {
margin: 0;
font-family: Arial, Helvetica, sans-serif;
}
.topnav {
position: relative;
overflow: hidden;
background-color: #333;
}
.topnav a {
float: left;
color: #f2f2f2;
text-align: center;
padding: 14px 16px;
text-decoration: none;
font-size: 17px;
}
.topnav a:hover {
background-color: #ddd;
color: black;
}
.topnav a.active {
background-color: #4CAF50;
color: white;
}
.topnav-centered a {
float: none;
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
}
.topnav-right {
float: right;
}
/* Responsive navigation menu (for mobile devices) */