The sidebar is not visible
Open Layout → Theme Options and check the setting for that page type. Use yes to show the sidebar and save the widget.
A navigation link opens the wrong page
Edit Main Navigation in Layout and confirm the destination. Work should normally use /search/label/Project?max-results=12, Journal /search?max-results=100, and the special pages should use their default Blogger page URLs.
The search panel opens but results are unexpected
Mira Vell sends the query through Blogger search. Check that your post/page titles and content contain the words you expect readers to search for.
Dark mode looks wrong in custom content
Remove hard-coded light background/text colors from custom HTML where possible. Theme-owned components already have coordinated light and dark styling.
Dark mode choice does not seem to persist
Test in a normal browser window with site storage/cookies allowed. Private browsing or aggressive privacy settings can prevent a site from remembering preferences.