How do I add a partial dashed border to an element?

Hey.

I'm looking for help on adding a dashed border to a section element - a border that is only visible on the bottom left of the element and 'roughly' 5% of the sections width, just like in this screenshot:

https://preview.redd.it/0wsbiy3oddze1.png?width=1342&format=png&auto=webp&s=6d06fbd050945ce33424d465bc5ca232a1bd83c3

Ideally I'd love to keep it to two dashes, any suggestions? (or alternatives)

<section>

<h2>

Heading

</h2>

<p>

Far far away, behind the word mountains, far from the countries Vokalia and Consonantia, there live the blind texts. Separated they live in Bookmarksgrove right at the coast of the Semantics, a large language ocean. A small river named Duden

</p>

</section>