stitch highlighting on visualization too light

[gabrielle-ohlson]

This issue is especially apparent for larger pieces—the light grey stitch highlighting can be quite difficult to detect when clicking on a line of code and looking for the stitch associated with it.

Could make to highlight a more obvious color, but another option could be to have a pop-up viewfinder that is zoomed into the stitch being highlighted (quick sketch of what that would look like below)