Shape & Color Palette
Tap a token, then tap cells
Internally this is still digits 1–9.
Visually: 1=circle, 2=line, 3=triangle, …, 9=nonagon.
Rules: each shape+color token must appear exactly once in every row, column, and 3×3 block.
It’s pure HTML/CSS/JS, no backend, no tracking. When we’re happy with it,
this ports cleanly into a mobile shell (Capacitor, React Native, Flutter, whatever mood you’re in that week).