<!DOCTYPE html>
<style>
#fixed {
    position: absolute;
    left: 300px;
    top: 200px;
    width: 100px;
    height: 100px;
    background-color: green;
}

#fixed-child {
    position: absolute;
    left: 25px;
    top: 25px;
    width: 50px;
    height: 50px;
    background-color: blue;
}
</style>
<div id="fixed">
    <div id="fixed-child"></div>
</div>