Borges defined the classic style in an essay called "The Postulation of Reality." He even uses the word "classical" several times in this essay and contrasts this style with the romantic style. I discovered this yesterday (I knew the essay before but hadn't made the connection) in my weekly conference with Thomas.
As is typical with Borges, he makes something very ordinary into something deeply strange-sounding. The classical trick of representing reality is not to represent or describe it, but conjure it up out of purely abstract schemata. This works because you don't actually need to paint with words or be expressive to make the reader imagine things.