PrismJS is a handy library which can help style your code snippets, like this:

TypeScript

const blah: string = test;

CSS

#selector {
  background-color: #fff;
}
.class-selector {
  font-size: 3rem;
}
pre {
  padding: 1rem;
}

HTML

<section>
  <header>
    <h1>Greetings!</h1>
  </header>
  <article>
    <p>Hello!</p>
    <p>Hi!</p>
    <p>Yo!</p>
  </article>
</section>