Certain style encapsulating almost every old Italian city (7)
I believe the answer is:
palermo
'italian city' is the definition.
(city in Italy)
'certain style encapsulating almost every old' is the wordplay.
'certain style' becomes 'perm' (hair style. I am not sure about the 'certain' bit.).
'encapsulating' indicates putting letters inside (inserted letters are absorbed or encapsulated).
'almost' means to remove the last letter (almost the whole word is kept).
'every' becomes 'all' (similar in meaning).
'old' becomes 'o' (abbreviation as in OT - Old Testament).
'all' with its last letter removed is 'al'.
'perm' placed around 'al' is 'palerm'.
'palerm'+'o'='PALERMO'
Can you help me to learn more?
(Other definitions for palermo that I've seen before include "Italian capital" , "Sicilian city" , "Capital city of Sicily" , "ity of Italy" , "Italian city" .)