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<p>Second item :nth-of-type(2)</p>
<ul class="one">
    <li>One</li>
    <li>Two</li>
    <li>Three</li>
    <li>Four</li>
</ul>

<p>Odd items :nth-of-type(odd)</p>
<ul class="two">
    <li>One</li>
    <li>Two</li>
    <li>Three</li>
    <li>Four</li>
</ul>

<p>The first two items :nth-of-type(-n+2)</p>
<ul class="three">
    <li>One</li>
    <li>Two</li>
    <li>Three</li>
    <li>Four</li>
</ul>
body{
  font-family: 'Arial';
}
ul{
  list-style: none;
  margin: 0;
  padding: 0;
}
li{
  background-color: #fff;
  padding: 10px;
}
.one li:nth-of-type(2) {
  background: #54c2ee;
}
.two li:nth-of-type(odd) {
  background: #54c2ee;
}
.three li:nth-of-type(-n+2) {
  background: #54c2ee;
}