baby blue
  noun  ,  pl   ⋯ blues
  1 [  noncount  ] : a very light blue color
  2 baby blues [  plural  ] informal : blue eyes
   She gazed into his baby blues.
  3 baby blues [  plural  ] informal : a feeling of sadness that a woman has after giving birth to a baby
   She had a bad case of the baby blues.
  — compare postpartum depression
  baby blue  adj  
   He was wearing baby blue pajamas.