I see that you have a cache plugin for this domain http://menofpurpose.fogwm.org/
you need to clear the cache after you update your Custom CSS.
And also check that the Theme Option settings for all your domains regarding Widgets are similar. Check your Theme Options -> Styling -> Enable Widget Title Black Background and Theme Options -> Styling ->Disable Widget Background. Make sure sub domain settings are same as main domain.
Sort out one issue first, before proceeding to another issue, or things can complicated.