I would love this even more if a lined or dotted grid remained in the dead space to differentiate the area of each clue.
In fact, a highlight of the 27 cells within the area of a clue on hover would be great as well.
Otherwise, fantastic work.
GitHub Issues (https://github.com/egraether/mine3D/issues)
Feature Requests (https://mine3d.uservoice.com/forums/136434-general)