Very interesting idea! The deck and card mechanics are actually very nice and are a really nice start to where you could take this. Some suggestions:
1) when you use a card, discard it instead of graying it out.
2) When you have too many cards in your hand you can't read all of what the cards say, so would be nice if the hovered card stood out a bit more.
3) Some feedback when you play a card would be nice because right now you click to use a card and you can't really tell anything different is happening
Great job, keep building it!