JSFiddle - React, Tailwind, and code Playground

HTML

<div class="parent">
    This is the parent div, it colors the <strong>strong in red</strong>
    makes a <small>small underlined</small>
    <h4>sets a margin-left 10px for a H4</h4>
    and many other stuff<br><br>
    <div class="child">
        this is the child element<br>
        here a <strong>strong should not be red</strong><br>
        <small>small should not be underlined</small>
        <h4>H4 should not have a margin-left</h4>        
        and so on...
    </div>
</div>

CSS

.parent>strong{
    color:red;
}
.parent small{
    text-decoration: underline;
}
.parent>h4{
    margin-left: 10px;
}

.child, .parent{
    border: solid thin black;
}