how to add a code snippet in html code example

Example: insert code snippet into html

<pre class="line-numbers">
  <code class="language-css">
    p { color: red }
  </code>
</pre>

/* The following language classes are supported:
language-markup – Use for HTML, XML, etc…
language-css
language-clike
language-javascript
language-java
language-php
language-scss
language-bash
language-python
language-sql
language-https
language-csharp
language-aspnet
language-scala
language-haskell
language-objectivec
language-latex
language-git */