Enjoying this take on workspace management! Thank you for this package.

As a consequence of defining activities-tabs-face like this:

(defface activities-tabs-face
  `((t :foreground ,(face-foreground 'font-lock-function-name-face nil 'default)))
  "Applied to tab-bar faces for tabs representing activities.")

the face does not change when the theme does, leading to mismatched/low-contrast tab bar name displays when I switch from a light to a dark theme. Consider replacing this with some combination of :inherit and the tab-bar defaults?