JSFiddle - React, Tailwind, and code Playground

HTML

<aside>
  <div class="container"> 
    <header class="headerTitle"> Header Title  </header> 
    <section class="sectionClass"> .  </section>
    <div class="rightSideDiv"> </div>
  </div>
  </aside>

CSS

.container {
  height: 500px;
  widht: 500px;
  background-color: red;
  display:flex;
  flex-wrap:wrap;
  justify-content:space-between;
}

.headerTitle {
  display: inline-block;
		height: 24px;
		margin: 24px 24px 0;
		padding: 0;
		line-height: 24px;
    width:100%;
}

.sectionClass {
  width:249px;
  height:200px;
    background-color: yellow;

}

.rightSideDiv {
    width:249px;
  height:200px;
  border: 4px solid green;
}