Challenge Mode is here. Every topic now has a harder question set that mixes difficulty levels and pushes beyond the standard problems — available with Pro. We also added streak tracking so you can see how many days in a row you've been putting in the work, per-topic accuracy on the home screen so you know exactly where you stand, and a skill breakdown at the end of every session so you can see which concepts you're nailing and which ones need another look. Questions are now de-duplicated across sessions, so you won't see the same problem twice until you've worked through the full bank. And "Back to Topics" actually takes you back to topics now.