If you don't have access to the CSS then you can use inline CSS and use a 'PUSH' method that does what it means, it pushes the content down the page, so its not overlapping. JsFiddle here: https://jsfiddle.net/SimonHayter/090ar1u0/
<div style="position: fixed; top: 0; left: 0; width: 100%; height: 40px;>
Hello, I am Menu, nice to meet you.
</div>
<div style="height:40px;width:100%;">
Let's push the page down 40px, you can't see me!
</div>
<div>
Existing Content
</div>
Or you could just edit the existing HTML to add margin-top
, i.e:
<div style="position: fixed; top: 0; left: 0; width: 100%; height: 40px;>
Hello, I am Menu, nice to meet you.
</div>
<div class="container" style="margin-top: 40px;">
This is where your existing content lives.
</div>
If you dislike inline CSS then you can simply add a <style>
after the body in HTML5, like so:
<body>
<style>
.menu {
position: fixed;
top: 0;
left: 0;
width: 100%;
height: 40px;
}
.container {
margin-top: 40px;
}
</style>
<div class="menu">
Hello, I am Menu, nice to meet you.
</div>
<div class="container">
Existing Content
</div>
</body>
If you don't have access to the HTML either then you can use Apache to Modifying static content using a CGI script.