Design of trendy shelter (6)
I believe the answer is:
intent
'design' is the definition.
(thesaurus)
'trendy shelter' is the wordplay.
'trendy' becomes 'in'.
'shelter' becomes 'tent' (tent is a kind of shelter).
'in'+'tent'='INTENT'
'of' is the link.
(Other definitions for intent that I've seen before include "Firm - plan - steadfast - purpose" , "'Engrossed, absorbed (6)'" , "Focused" , "'Purpose, aim (6)'" , "Purpose, design" .)