JSFiddle - React, Tailwind, and code Playground

HTML

<div class="app">
  
  <p>Hai App Paragraph</p>
  <br>
  <a href="">Hai App Anchor</a>

  <div class="modal-body">
    <p>Hai Modal Paragraph</p>
    <br>
    <a href="">Hai Modal Anchor</a>
  </div>
</div>

CSS

p, a {
  color: red;
  font-size: 2em;
}

div.app p {
  text-decoration: underline;
  /* 
  note this does apply in the .modal-body 
  b/c the selector below is not very specific
  */
}

.modal-body * {
  all: initial;
  /* https://caniuse.com/?search=all */
}

.modal-body {
  border: 1px solid black;
}