<!doctype html>
<meta charset=utf-8>
<style>
html, body {
    margin: 0;
}
section {
    position: absolute;
    background: rgb(255, 0, 0);
    width: 30px;
    height: 30px;
    top: 30px;
    left: 30px;
}
</style>
<section></section>