Swap the landing-page hero from a static `<img>` (white-faced —
which glared as a light box on the dark theme) to an INLINE svg
whose linework uses `fill: currentColor` and whose faces are
transparent. The wireframe now inherits the theme text colour
(`svg.hero-logo { color: var(--pst-color-text-base); }`) and the
page background shows through, so it flips correctly with the
light/dark toggle.
- `tractor_logo_hero.html`: the inline svg partial (`.st0` ->
`currentColor`, `.st1` -> `none`), `.. raw:: html :file:`-d into
`index.rst`,
- the shared `tractor_logo_side.svg` is untouched here (navbar +
favicon still ride it).
(this patch was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code