Website there designs features to be firmly attached (8)
I believe the answer is:
tethered
'be firmly attached' is the definition.
(to tether is to attach or tie)
'website there designs features' is the wordplay.
'features' indicates the answer is hidden within the clue (I've seen 'featuring' mean this).
'TETHERED' can be found hidden inside 'website there designs'.
'to' is the link.
(Other definitions for tethered that I've seen before include "Confined in range by tied rope" , "Of animal, secured or hobbled" , "Bound" , "Tied to something with a rope" , "Of animal, with rope fastened to prevent straying" .)