Folds in pastel design (6)
I believe the answer is:
pleats
'folds' is the definition.
(pleating is a kind of folding)
'pastel design' is the wordplay.
'design' is an anagram indicator.
'pastel' with letters rearranged gives 'PLEATS'.
'in' acts as a link.
(Other definitions for pleats that I've seen before include "Creases, folds" , "Staple for cloth folds" , "Double folds in garments" , "As before, twists" , "Folds sewn or pressed into cloth" .)