JSFiddle - React, Tailwind, and code Playground

HTML

<div id="theme" class="theme1">
    <div id="header" class="handle noback">
    </div>
</div>

CSS

#header {
width:100%;
height:200px;
}

#theme.theme1 .handle {
   background:blue; 
} 

#header.noback { 
   background:none;   
}