- 🇪🇸Spain juanolalla
I'm reopening the issue because despite the previous solution was considered not applicable, the problem is still there.
I think this is a pretty common use case, where you want to use the module and start by using the default css that comes with it (in tablesortertheme.css), like the header sorter images (arrows) and the rest of base theming. You could then adjust that with your own css in the theme.
Right now this is not possible, unless you select green or blue, and then you would need to override the css to remove that blue or green extra theming.
I understand that the first option was intended to be just the "System Default" theme, which means no specific css at all; and so for, adding tablesortertheme.css to that could be considered inappropriate and alter the styling of other sites with existing custom css without that file.
So I came with a different and simple solution from this missing use case: to create a new option to select "Tablesorter's Default" theme, so that way a user can count on the base css from tablesortertheme.css, without having to choose unwanted blue or green theme. Attaching the patch.