style sheet vs sheet of paper

style sheet and sheet of paper both are nouns.

Word	Noun	Adjective	Verb	Adverb
style sheet	Yes	No	No	No
sheet of paper	Yes	No	No	No

As nouns, sheet of paper is a hypernym of style sheet; that is, sheet of paper is a word with a broader meaning than style sheet:

style sheet: a sheet summarizing the editorial conventions to be followed in preparing text for publication
sheet of paper: paper used for writing or printing

Other hypernyms of style sheet include piece of paper, sheet.

style sheet (noun)	sheet of paper (noun)
a sheet summarizing the editorial conventions to be followed in preparing text for publication	paper used for writing or printing