JSFiddle - React, Tailwind, and code Playground

by Torwan

HTML

<div class="table">
  <div class="row">
    <div>col 1</div>
    <div>col 2</div>
  </div>
  <div class="flex">
    <div class="red">colspan 2</div>
  </div>
</div>

CSS

div.table {
  display: table;
  width: 100%;
}

div.table>div.flex {
  display: flex;
  width: 100%;
  border: 1px solid gray;
  flex-direction: horizonal;
}

div.table>div.flex>div {
  display: block;
  flex-grow: 1;
  border-bottom: 1px solid #ddd;
  vertical-align: middle;
  height: 30px;
  padding: 4px;
  width: 100%;
}

.red {
  background: red;
}

div.table>div.row {
  display: table-row;
  border: 1px solid gray;
  flex-direction: horizonal;
}
div.table > div.row > div {
  display: table-cell;
  width:50%;
}