All 3 Uses

theme
in
The Perks of Being a Wallflower
(Auto-generated)

He is always making mix tapes for my sister with very specific themes. One was called "Autumn Leaves."
p. 10.6 *

themes = an idea that is unifying or recurrent
He was the boy that made mix tapes with themes and hand-colored covers until he hit my sister and stopped crying.†
p. 11.7
I already have the songs picked and a theme.†
p. 61.7

Definitions:

(1) (theme as in: theme of the novel)
a basic idea that underlies what is being said or done -- especially in a literary or artistic work
(2) (theme as in: musical theme)
the initial or primary melody of a musical composition

or

(as in "theme song") music that is most repeated in a film, television series, or other theatrical production
(3) (theme as in: wrote a 2-page theme on my summer)
an essay written by a student

(This sense of theme is much rarer in recent decades than in the past.)
(4) (meaning too rare to warrant focus)