Creating Collapse Sliding Side Panel in CSS

gistfile1.txt

<style type="text/css">
// source: https://www.apphp.com/index.php?snippet=css-collapsible-sliding-side-panel
// You may define side panel, that will slide whether on button click on on window size changing. 
#sidepane{
        display: block;
        position: absolute;
        transform: translateX(-100%);
        transition: transform ease-out 0.2s;
}
#sidepane.fadeIn{
        transform: translateX(0%);
        transition: transform ease-out 0.3s;
}
</style>