Style combines two elements: the idea to be expressed and the individuality of the author.  Just as no two personalities are alike, no two styles are exactly alike.  It has been observed that even infants have individual styles.  Even in so limited a medium as Morse code, each sender has s tyle, called a "fist."

Style includes diction, connotations of the diction, imagery, rhythm, repetition, coherence, emphasis, and arrangement of ideas.