one more, for completeness:

  SELECT 'black' AS outline_color
  FROM elements parent
  JOIN elements child ON parent.id = child.parent_id
  WHERE parent.data_theme = 'light'
    AND child.data_theme = 'dark'
    AND child.focused = true

there's a lot of ways to express the same thing! it's interesting to notice the connections between them, I think, and their strengths and weaknesses, e.g. I probably wouldn't want to write my whole design system in SQL, but since it's relational queries over the elements structure and properties, you could.