Edges into study, bright red (7)
I believe the answer is:
crimson
'bright red' is the definition.
(I've seen this before)
'edges into study' is the wordplay.
'edges' becomes 'rims' (rim is a kind of edge).
'into' indicates putting letters inside.
'study' becomes 'con' (I've seen this before).
'rims' going within 'con' is 'CRIMSON'.
(Other definitions for crimson that I've seen before include "Become red-faced" , "Blush" , "Bright red" , "Flush" , "Rich deep red" .)