JSFiddle - React, Tailwind, and code Playground

HTML

<fieldset>
<div>A</div>
<div>B</div>  
<div>C</div>  
<div class="hide">D</div>
<div class="hide">E</div>
</fieldset>
<fieldset>
<div>A</div>
<div class="hide">B</div>  
<div>C</div>  
<div>D</div>
<div class="hide">E</div>
</fieldset>

CSS

.lastvisible { background: yellow }
.hide { display: none }
fieldset { margin-bottom: 30px; padding: 10px; border: 1px solid #ddd }
body { font-family: sans-serif; margin: 1em }

JavaScript

var divs = document.getElementsByTagName('div');
for (i = 0; i < divs.length; i++) {
	if (!divs[i].classList.contains("hide")) var last = divs[i];
}
if(last) last.classList.add("lastvisible");