Drawer 5 sun box

I'm starting to make the Drawer 10 steps 5 sun Japanese puzzle box, Himitsu-bako (https://www.japanesepuzzlebox.jp/product/32). Because it's out of stock now, and it's one of the very popular Himitsu-bako. The way to open this puzzle box is that the first side uses a 7 steps mechanism, which is the same as a normal 7 steps puzzle box. The second side opens the drawer in 3 steps, making a total of 10 steps. This box is divided into two compartments (top and bottom), which operate separately. The drawer side will not open unless the first 7 steps side is opened. The upper compartment is for the 7 steps mechanism, and the lower compartment is for the 3 steps drawer mechanism.

The 7 steps space is the main part, and it is 27mm deep. Therefore, the drawer space is a bit smaller at 24mm. The drawer body is stored inside it (24mm), so the inner space of the drawer is about 100x66x14mm. It's pretty small and only holds cards, etc., so I'm wondering if it could be made a bit bigger. That's the challenge with this box.

The drawer lid panels are completely removable, so they tend to warp. I used to make this lid panel out of normal wood, but the panels tend to warp. Now, I make them by gluing slices of walnut or other wood to an MDF board. To be continued...