Counter-increment

The CSS   property acts like an incremented variable in a programming language - it specifies the amount to increment the specified counter by when the current CSS selector is encountered. The property lists one or more counter labels, each followed by an optional increment integer value (default increment is 1). Negative integers and zero are also valid.

If a counter is incremented and rendered using a single CSS selector (with the  property and  /  pseudo-elements), it should be incremented first, then rendered. If a single CSS selector both increments and resets a counter, it is reset, then incremented.

Values
CSS examples: