<div>I don't have any class, but at least one of my children has, so I have a border.
  <p class="any-class">Child with 'any-class'</p>
  <p>Child without any class</p>
  <p>Child without any class</p>
</div>
<br>
<div class="any-class">None of my children has any class, but I do have, so I have a border too.
  <p>Child without any class</p>
  <p>Child without any class</p>
  <p>Child without any class</p>
</div>
<br>
<div>Neither I nor any of my children have any class, so I have no border.
  <p>Child without class</p>
  <p>Child without class</p>
  <p>Child without class</p>
</div>

html {
  padding: 10px;
  font-size: 20px;
}