JSFiddle - React, Tailwind, and code Playground

HTML

<div class="wrapper">
  <div class="box a">A</div>
  <div class="box b">B</div>
  <div class="box c" id="boxc">
    <div class="workaround">
    <h1>
      The heading in question!
    </h1>
    
    </div>
  </div>
  <div class="box d">D</div>
  <div class="box e">E</div>
  <div class="box f">F</div>
</div>

CSS

.wrapper {
  display: grid;
  grid-template-columns: 100px 100px 300px;
  grid-template-rows: 200px 200px;
  grid-gap: 10px;
  background-color: #fff;
  color: #444;
  align-content: space-evenly;

}

.workaround{
  border: 1px solid green;
  margin: 0;
  padding: 0;
  height: 100%;
  width: 100%;
  display: table;
  
}
h1{
  font-size: 1em;
  border: 1px solid yellow;
  display: table-cell;
    vertical-align: middle;
}

#boxc{
 background: red;
  
}

.box {
  background-color: #444;
  color: #fff;
  border-radius: 5px;
  padding: 20px;
  font-size: 100%;
}