JSFiddle - React, Tailwind, and code Playground

by Sergey Linnick

HTML

<div class="row">
  <div class="one">1</div>
  <div class="two">2</div>
  <div class="three">3</div>
</div>

CSS

.row{
  display: flex;
  flex-wrap: wrap;
}

.row > div{
  border:1px solid;
}

.one{
  width: 50%;
}

.two{
  width: 50%;
}

.three{
  width: 100%;
}

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