JSFiddle - React, Tailwind, and code Playground

HTML

<div id="outside">
<div id="div1">
    <h1>margin</h1>
</div>

<div id="div2">a
    <h1>no-margin</h1>
</div>
</div>

CSS

#outside {
    background-color: #ccc;
    border:1px solid #000;
}
#div1 {
  background-color: #66d;
}
#div1 h1 {
  margin: 20px 0 0 0;
}
#div2 {
  background-color: #6d6;
}
#div2 h1 {
  margin: 20px 0 0 0;
}