JSFiddle - React, Tailwind, and code Playground

HTML

<div class="wrapper">
  <div id="inner1">
     LINE1  
  </div>
  <div id="inner2">
    LINE2 
  </div>
    <div class="clear"></div>
</div>

CSS

.wrapper{
    width:400px;
    overflow: auto;
    background-color: #0FC;
}
#inner1{
    float: left;
    width: 40%;
    margin-right: 5%;
    margin-left: 5%;
    background-color: #69C;
}
#inner2{
    float:left;
    width: 20%;
    margin-left: 5%;
    margin-right: 5%;
    background-color: #C09;
}
.clear
{
    clear:both;
}
}