In the example above, four values are added. A set of double smart quotes and a pair of single smart quotes. It's slightly confusing as each quote is wrapped in quotes - but those are just programatic quotes (could be double (") or single (')) as anywhere else in CSS. The quotes inside are what will be used on the page.
There are four values for the content property that relate to the quotes property: open-quote, close-quote, no-open-quote, and no-close-quote.
The first...