JSFiddle - React, Tailwind, and code Playground

HTML

<div class="side">
  <div id="ad">
    bla
  </div>
  <div id="rss_news">
    double bla
  </div>
</div>

CSS

.side {
  float: left;
  background-color: rgba(0,0,0,0.3);
  width: 300px;
  min-height: 710px;
  padding: 0 0 0 0px;
  margin-top: 25px;
  border: 1px solid white;
  border-radius: 8px 8px 8px 8px;

 }

 #ad {
   border: 1px solid blue;
   height: 320px;
   max-height: 350px;
   margin: 15px;

 }

 #rss_news {
   border: 1px solid yellow;
   height: 320px;
   max-height: 350px;
   margin: 15px; 
 }