JSFiddle - React, Tailwind, and code Playground

by adelura

HTML

<div class="one">
  <div class="inner"></div>
</div>

<div class="two">
  <div class="inner"></div>
</div>

CSS

:root {
  --border-size: 50px;
}

.one, .two {
  width: 100px;
  height: 100px;
  border: var(--border-size) solid red;
  position: relative;
  margin: 10px;
}

.inner {
  position: absolute;
  border: 2px solid black;
}

.one .inner {
  top: 0;
  right: 0;
  left: 0;
  bottom: 0;
}

.two .inner {
  top: calc(var(--border-size) * -1);
  right: calc(var(--border-size) * -1);
  left: calc(var(--border-size) * -1);
  bottom: calc(var(--border-size) * -1);
}