I use an e-ink phone (Hisense A5) and would like a high contrast theme similar to Toner (https://openmaptiles.github.io/maptiler-toner-gl-style (https://openmaptiles.github.io/maptiler-toner-gl-style)). The OSM theme definition can be found on GitHub https://github.com/stamen/toner-carto (https://github.com/stamen/toner-carto).
I know nothing about theme development. Could someone point me to useful resources? Ideally a walk-thru to convert an OSM theme to Locus. (or even better, a Locus port of the OSM theme :) )