JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
    <div class="col1">
        col1
    </div><div class="col2">
        col2
    </div>
</div>

CSS

.container {
    width:100%;
     height:100%
}
 
.col1 {
  display: inline-block;
  width:15%;
  height: 50%;
  margin: 0;
    padding: 0;
  background: #ff8888;
 }

.col2 {
  display: inline-block;
  width: 85%;
  height: 100%;
    margin: 0;
    padding: 0;
  background: #ffff66;
}