When I unticked “theme can be selected by users” for the Dark theme, a duplicate Light theme appeared in the theme list. My modifications should have been to the selected default one. I’ve now unticked “can be selected by users” for the duplicate Light theme and it moved down to inactive. So now the only active theme is Light and is has only “enabled by default” checked. The color scheme is Light (not “Light Scheme” – which is in the dropdown list – I didn’t change this). My test changes to the footer page are in the selected theme. I also have some additional CSS in the CSS section to remove the user stats from the About page – that worked OK.