<!DOCTYPE html>
<html>
<head>
<title>Title of the document</title>
<style>
#example {
top: 50%;
left: 50%;
width: 30em;
height: 18em;
transform: translate(-50%, -50%);
border: 1px solid #666;
background-color: #b9faac;
position: fixed;
}
</style>
</head>
<body>
<div id="example"></div>
text
<br> text
<br> text
<br> text
<br> text
<br> text
<br> text
<br> text
<br> text
<br> text
<br> text
<br> text
<br> text
<br> text
<br> text
<br> text
<br> text