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Well, quite responsive but so much for accessibility... There's still a lot of work for it to be complete but the templates for each category are OK.

I spent hours on this one... Trying to make the flipping cards work properly, first with each half card independently, then with just the whole card and... never succeed... You can see these fails on the branches of my repo. Well, I guess I'm done with this one, at the moment anyway. It's frustrating to leave it that way.

The linear gradients were kind of tricky, especially for the dark mode toggle button. It makes the CSS stylesheet a bit messy. Also, the approximate selectors' names don't help too much on that matter. I really would have liked to test it with PHP with real data (but I may try that later).