These are the single source of truth for the library's palette. Widgets mustread colours from here instead of writing literal rgb() calls: the librarypreviously carried a dark token set that only window() and progress_bar()consumed, while every other widget hard-coded light values of its own.
The seam between two unopened tiles. Sits a step mines_ground darker(slate-400 -> between slate-400 and slate-500) so an untouched field readsas a grid of tiles instead of one flat slab: at the default zoom the fieldis almost entirely unopened, and with no seams at all it collapsed into afeatureless grey mass that looked blank.
Minesweeper digging ground: the unopened earth of the demo board. Mustread clearly darker than every surface so dug-out white pits contrast ata glance, even zoomed far out.
Unopened tile under the pointer. One step lighter than mines_ground(slate-300 vs slate-400) - deliberately not white, so "hovered earth" isnever mistaken for a dug-out pit.