The most common and most likely answer to this crossword clue is the 3 plus 3 letter word POP ART
I've seen this crossword clue in The Sunday Telegraph
P
O
P
A
R
T
More clues leading to the result POP ART
- Lichtenstein espoused it as an interest outside work
- Role outside work in modern movement
- Representations of modern culture left around the state
- Commercial designs go alongside flower
- ‘Whaam!’ is an example of this work, in part
- Modern painting perhaps showing stretch of Italian river?
- Modern work — revolutionary work with character
- Work in district, modern style
- Such painting means work during leave
- Movement of Paolozzi, primarily overcoming movement of Riley, primarily
Buddy explains!
The straight part
We know that "modern style" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case modern style = pop art.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.