You should add some kind of almanac (not the deck menu type) that's basically an almanac of all stones from 1 to 100, the special stones (negative 1, 0, x, mirrorstone) and the tools plus maybe some the stones after 100.
The almanac should also have some kind of unlock-to-view thing. I'd say that all non-composite stones get unlocked in the almanac when you get them (e.g. you can view 13 in the almanac when you beat the 13-prime master) and composite stones get unlocked when you craft them. (e.g. you can view 6 after you create the 6-gem, by merging a 2 and 3 gem together)
When you hover over the first card in your deck, sometimes it says “View your deck” instead of saying what the first stone does. This is annoying
Save data is saved in the path "idbfs/Strategems". Maybe you have high-privacy browser settings set to wipe this data when closing your browser? Have other browser-based Unity games been saving fine for you?
(For me, using a Private Window in Firefox results in new save files which last for only that window, so it may be something similar to that.)
