We need to talk about Shadow DOM. While the Google official docs strongly encourage the use of Shadow DOM, I quite strongly disagree.
As an example, a couple weeks ago I realized I could style the <summary> part of a <details><summary> set of elements as a button, which would look great and more readily indicate its function. You can see the improvement here:
Thankfully I hadn’t swallowed the party-line on Shadown DOM and this is the full set of CSS changes I had to make, just the following additions: