One covered fashion's mode of existence (9)

'one covered fashion's' is the definition.
I know nothing about this answer so I cannot judge whether this works.

'mode of existence' is the wordplay.
I cannot really understand how this works, but
'mode' could be 'style' (synonyms) and 'style' is found within the answer.
'existence' could be 'life' (being alive) and 'life' is found in the answer.
This accounts for all the letters.
This explanation may well be incorrect...

Can you help me to learn more?