<ul>
  <li>リスト1</li>
  <li>リスト2</li>
  <li>リスト3</li>
  <li>リスト4</li>
  <li>リスト5</li>
</ul>
ul li{
  background-color: #fff;
  list-style: none;
}

ul li:nth-child(odd){
  background-color: #ccc;
  color: #fff;
}

External CSS

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External JavaScript

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