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 i,
  j,
  last,
  divs,
  fieldsets = document.getElementsByTagName('fieldset');

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