The Pro/Legacy add-on bars (`#111`) and release milestone elements (`#56334b`) were near-invisible in dark mode — both colours have contrast ratios below 1.5:1 against a typical dark background. ## Changes (`docs/_static/css/support-chart.css`) - Introduce two CSS custom properties (`--chart-pro-fill`, `--chart-milestone-color`) set to Canonical standard colours in dark mode: warm grey `#aea79f` and mid-light aubergine `#cd7c97` - Apply via `var()` with the original values as fallbacks, so **light mode is completely unchanged** - Cover both Furo's manual theme toggle (`html[data-theme="dark"]`) and OS-level preference (`@media (prefers-color-scheme: dark)`, excluding explicit `data-theme="light"` overrides) ```css @media (prefers-color-scheme: dark) { html:not([data-theme="light"]) { --chart-pro-fill: #aea79f; --chart-milestone-color: #cd7c97; } } html[data-theme="dark"] { --chart-pro-fill: #aea79f; --chart-milestone-color: #cd7c97; } .chart__bar--black { fill: var(--chart-pro-fill, #111); } .chart__milestone { stroke: var(--chart-milestone-color, #56334b); } .chart__milestone-release { fill: var(--chart-milestone-color, #56334b); } ``` **Before (dark mode)** — Pro bars and milestone markers invisible:  **After (dark mode)** — all three bar types and milestone elements clearly visible: