JSFiddle - React, Tailwind, and code Playground

HTML

<div class="outer">
    <div class="inner">
        My content...
    </div> 
</div>

CSS

.outer {
    background-color: lightgrey;
}	
.inner {
    background-color: green;
    padding: 50px;
    width: 600px;
    margin:10px;
    display: block; /* No top, bottom margins applied.  Does apply them with "inline-block".  Why? */ 
}