Hwy Grga,
Maybe a bit late, but I would totally second the idea to put the searchbar on top to avoid scrolling on mobile devices!
Yes, I have seen your reply above, but let me explain:
The biggest advantage of your tool lies in its mobility. For complex and comfortable spellbook building I would still take octgn. The UI is very good there in my opinion besides very minor things.
But what the community was missing so badly was a builder for instant moments. You have an idea at work - look it up. You have an card text issue in a discussion - look for the card. And so on. THAT is for me the best part of spellbook building to think through ideas whenever you want. And that is the point where your builder shines and it would shine even brighter with optimization for mobile use (without destroying the usability for computer).
And of course academy is the missing part right now