"He wears a light blue shirt."
Translation:Αυτός φοράει ένα γαλάζιο πουκάμισο.
What I see are: (Αυτός) φοράει for "he wears" and "ένα γαλάζιο πουκάμισο" for "a light blue shirt". That is not the entire sentence.
And yes "ένα γαλάζιο πουκάμισο" is three words together" but the computer algorithm requires that in order to have the comment at the head of the list we need to include more information. It's a technical issue.
This is shown in the Tips & hints for colors.
See here for the declension: http://www.neurolingo.gr/online_tools/lexiscope.htm?term=%CE%B3%CE%B1%CE%BB%CE%AC%CE%B6%CE%B9%CE%BF%CF%82
and here for the Tips & notes for the Color Skill ->https://www.duolingo.com/skill/el/Colors/tips-and-notes