Display the value of an HTML attribute in bullets of an HTML list with CSS

Instead of simple dots, I wanted the list bullets of the index of my blog to be the date at which articles were written. It turns out HTML+CSS can do that easily.
Here is how I created a list with custom bullets, taking their value from an HTML attribute.

The HTML markup of my index page, note the year="2020" attribute on the <li> element:

<ol class="pages">
  <li year="2020">
    <a href="/my-article/">My article of 2020</a>

And the CSS magic. we customize the bullet with ::marker and read the HTML attribute with attr().

.pages {
    padding-inline-start: 6ch;

  .pages li::marker {
    content: attr(year) " - ";

Here is how it displays:

Screenshot of a list with custom bullets

You can achieve a lot with just HTML+CSS, the stack powering this blog and my other web pages.