DeskClock: Sync /e/ UI changes with Q branch

* This is a combination of the following 5 commits.

  3425-Q-Fix_theme_consistency

  3649-Q-color_issue_in_light_mode

  3808-Q-Forcefully_enable_dark_mode

  3870-Q-snoozed_background_color_issue

  3948-Q-Fix_timer_background_color_issue