I'm having an awful time sub-theming Basis. I've followed the guide (the excellent https://backdropcms.org/news/build-sub-theme-basis-default-frontend-them...) and get no where. I'm not new to sub-theming in D7 and have a functional Bootstrap-Lite subtheme running on this dev site, but wow, I can't figure out what's wrong.
Starters - running Mamp-Pro, v 5.7. and Backdrop 1.15, subtheme name is machine friendly "mm_basis", in the site_name/themes directory. Per another post on theming troubles I disabled the Color module. And I'm flushing caches all the time.
So if I start with a blank sub-theme, populated with nothing but a mm_basis.info file (per the Ruvalcaba example) I get to select it at admin/appearance and the result is a WSOD. Add in "base theme = basis" to the .info file and same result. Add just the skin.css file and call it in .info, WSOD. Just give up and copy over all the CSS, templates, etc and still WSOD. Really give up and just copy over the entire Basis directory, rename the directory and .info and still WSOD. I of course can still get to /admin and reset the theme to Basis.
the Mamp php log just has a cryptic: PHP Fatal error: Cannot redeclare basis_breadcrumb() (previously declared in /Applications/MAMP/htdocs/site-dev/core/themes/basis/template.php:97) in /Applications/MAMP/htdocs/site-dev/themes/mm_basis/template.php on line 97
I think I've check all the obvious problems ... which are almost entirely naming & file permissions. Given that I have a working Bootstrap_lite subtheme, clearly MOST of the system is functioning. Its always some little, stupid thing. Can anyone point me to the little thing?