Feature Request

Add a black and white (grayscale) OSM background layer option with less contrast.

Context

This would provide an alternative base layer style that is more subtle and better suited for emphasizing overlays and transit data visualization.

Suggested Implementation

• Create or integrate a grayscale OSM style definition
• Reduce contrast to make the background less prominent
• Add as an option in the layer switcher (alongside existing OSM and aerial options)

References

• PR: Migrate from Mapbox GL to MapLibre GL with deck.gl for animations #1592
• Originally suggested by @greenscientist as a nice-to-have feature