pixels are predictable
HTML
<ul>
<li>this is parent
<ul>
<li>this is child
<ul>
<li>this is grandchild
<ul>
<li>this is great-grandchild</li>
</ul>
</li>
</ul>
</li>
</ul>
</li>
</ul>CSS
li {
font-size: 24px;
}