JSFiddle - React, Tailwind, and code Playground

HTML

<div id="gallery">
    <ul>
        <li>this</li>
        <li>this</li>
        <li>that</li>
        <li>this</li>
        <li>that</li>        
        <li>that</li>
    </ul>
</div>

CSS

#gallery ul {
display:block;
position:absolute;
/*auto calculated from javascript */
}

JavaScript

setTimeout(function(){
   var posVar = 50;        
   $('#gallery ul').css("right", '50px');
},300);