Heatmap Grid

A labeled heatmap grid on a GitHub-style green scale. Each cell scales up and deepens from an empty near-black square through four greens in proportion to its value, and the cells reveal as a diagonal wave that sweeps across the grid, with the hottest cells picking up a soft green glow and a Less to More legend keying the scale.

Provide the values as the DATA matrix of rows on a 0 to 1 scale, aligned to the ROW_LABELS and COL_LABELS arrays; the cells interpolate through the GITHUB_LEVELS color ramp, which you can swap for any palette. CELL and GAP set the density and DIAG_STAGGER and CELL_REVEAL set the wave speed. Color mixing and cell reveal are pure interpolate() over the frame, so the grid is deterministic and lands on a fully colored state. Use it for contribution calendars, cohort retention grids, and usage by time of day.