Have such styles only one vital difference? (6)
I believe the answer is:
unisex
'have such styles only' is the definition.
I can't tell whether this defines the answer.
'one vital difference?' is the wordplay.
I cannot really see how this works, but
'one' could be 'un' (northern English dialect form of 'one') and 'un' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for unisex that I've seen before include "Suitable for male and female" , "Common to both genders, say clothes" , "For both males and females" , "Available to men and women, clothes or hairdressing salons" , "like St Hilda's now, > but not St Trinian's!" .)