Making uniform suit hems, with dyed top, appearing outside (13)

'appearing outside' is the definition.
The definition suggests a present participle verb which matches the answer.

'making uniform suit hems with dyed top' is the wordplay.
I cannot really understand how this works, but
'with' could be 'and' and 'and' is found in the answer.
'top' could be 'star' (eg a top player is a star player) and 'star' is located in the remaining letters.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?