Overwriting blue links with...blue links that fail WCAG2 and have no pseudo-classes.

Replacing the default down arrow in <details> with...a down arrow SVG.

Delete it from the page and the main changes are 1. no rounded corners 2. content can possibly be larger than 800px

What's the point of this "library?"

> Use it in other projects

That's the place not to use this. This is just "I think browser defaults should look like this." Use it in any other project and all these element-based rules have a different specificity than the class-based ones. Have fun!