Resting tiles are solid

#Context

An earlier version drew a resting tile as a transparent outline: an edge with the ground showing through. A real player read that look as unfinished, a placeholder rather than a tile.

The sources record the change and its reason, but not the release it shipped in, so this record has no version.

#Options

#Decision

A resting tile is a solid fill: --tile fill, a 2.5px edge in the same --tile, and a --tile-ink letter, so it reads as a tile, not a placeholder.

Once rest was no longer empty, selection needed a state of its own. A lit tile takes --select fill, a --select-stroke edge and a --select-ink letter. The edge width never changes between states (box-sizing: border-box), so lighting a tile never shifts the grid.

#Evidence

One player's reading, recorded in the spec ("A real user read the old transparent-outline resting look as 'unfinished'") and in the code's own note on .tile. There was no wider test.

#Consequences

• Lit needs a different colour and an edge. In dark mode the resting fill is already the light colour, so selection needs a genuinely different fill. A fill change alone wasn't enough: in dark mode it was a close shift that was easy to miss, and in light mode a tile without a defined edge could merge with the grid gaps. So every lit tile carries a stroke.
• Fill, edge and opacity change together, never one without the others, or the edge snaps while the fill fades.
• The solid tile became one of the board's three states that the rest of the system borrows: the podium's 1st column is a solid tile (D-007), and so are the confetti's plain pieces.
• See Tile for every state.