<ul>
  <li>HTML</li>
  <li>CSS</li>
  <li>JavaScript</li>
</ul>
<ol id="lecture">
  <li>HTML</li>
  <li>CSS
    <ol>
      <li>selector</li>
      <li>declaration</li>
    </ol>
  </li>
  <li>JavaScript</li>
</ol>
ul li {
  color: red;
}

#lecture>li {
  border: 1px solid red;
}

ul,ol {
  background-color: powderblue;
}

External CSS

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External JavaScript

This Pen doesn't use any external JavaScript resources.