<html>
<head>
<style>
body {
    padding: 0;
    margin: 0;
}
.topbar {
    position: fixed;
    top: 0;
    background: rgba(0, 0, 0, .75);
    color: white;
    width: 100%;
    height: 32px;
    font-size: 20px;
    text-align: center;
    border-bottom: 4px solid red;
}
.content {
    font-size: 16px;
    padding-left: 10px;
    padding-right: 10px;
}
.header {
    font-size: 20px;
    margin-bottom: 5px;
    border-bottom: 1px solid gray;
}
</style>
</head>
<body>
<div class='topbar'>Topbar</div>
<div 