JSFiddle - React, Tailwind, and code Playground

HTML

<div id="columns" class="clearfix">
    <div class="column-1"></div>
    <div class="columns-2">        
        <div class="column-2"></div>
        <div class="column-3"></div>
    </div>
</div>

CSS

*,
*:before,
*:after {
  -webkit-box-sizing: border-box;
     -moz-box-sizing: border-box;
          box-sizing: border-box;
}

.clearfix:before,
.clearfix:after {
  display: table;
  content: " ";
}

.clearfix:after {
  clear: both;
}

#columns {
    display: block;
    width: 100%;
    border: 1px solid #333;
}

.columns-2 {
    margin-left: 200px;
}

.column-1,
.column-2,
.column-3 {
    float: left;
    height: 40px;
}

.column-1 {
    width: 200px;
    background: #f00;
}

.column-2,
.column-3 {
    width: 50%;
}

.column-2 {
    background: #ff0;
}

.column-3 {
    background: #0f0;
}