I'm struggling to understand a problem in my nested list. When I set the height of LI elements, they end up overlapping each other. Can someone explain why this is happening and suggest a proper way to apply height without causing this overlap effect? (I specifically want to adjust the height, not use padding or margins.)
.aaa {background:#ccf;}
.bbb {background:#fcc;}
.bbb li {height:25px;}
<ul class="aaa">
<li>one one one</li>
<li>two, too
<ul>
<li>alpha</li>
<li>beta</li>
<li>gamma</li>
</ul>
</li>
<li>three</li>
<li>here comes four</li>
</ul>
<ul class="bbb">
<li>one one one</li>
<li>two, too
<ul>
<li>alpha</li>
<li>beta</li>
<li>gamma</li>
</ul>
</li>
<li>three</li>
<li>here comes four</li>
</ul>