JSFiddle - React, Tailwind, and code Playground

HTML

<div class="mainrow">
  <div class="cols"></div>
  <div class="colm">dsjfhkjd hfkjdfh gkfdjhg dsjfhkjd hfkjdfh gkfdjhg dsjfhkjd hfkjdfh gkfdjhg dsjfhkjd hfkjdfh gkfdjhg dsjfhkjd hfkjdfh gkfdjhg dsjfhkjd hfkjdfh gkfdjhg dsjfhkjd hfkjdfh gkfdjhg dsjfhkjd hfkjdfh gkfdjhg dsjfhkjd hfkjdfh gkfdjhg dsjfhkjd hfkjdfh gkfdjhg dsjfhkjd hfkjdfh gkfdjhg dsjfhkjd hfkjdfh gkfdjhg dsjfhkjd hfkjdfh gkfdjhg </div>
  <div class="cols"></div>
</div>

CSS

.mainrow {
  display: flex;
  width:100%;
  background-color:yellow;
}

.colm {
  width:300px;
  background-color:white;
  border:1px solid red;
}

.cols {
  flex: 1;
  padding:10px;
  background: url("https://cdn-icons-png.flaticon.com/128/98/98233.png") repeat;background-position:top;background-attachment:fixed;
  border:1px solid green;
}