The system descriptor specifies which algorithm will be used to construct the counter’s representation based on the counter value. For example, cyclic counter styles just cycle through their symbols repeatedly, while numeric counter styles interpret their symbols as digits and build their representation accordingly.

]]> The first <symbol> in the value is prepended to the representation when the counter value is negative. The second <symbol>, if specified, is appended to the representation when the counter value is negative.

]]> The prefix descriptor specifies a <symbol> that is prepended to the marker representation. Prefixes are only added by the algorithm for constructing the default contents of the : pseudo-element; the prefix is not added automatically when the counter() or counters() functions are used. Prefixes come before any negative sign.

]]> The suffix descriptor specifies a <symbol> that is appended to the marker representation. Suffixes are only added by the algorithm for constructing the default contents of the ::marker pseudo-element; the suffix is not added automatically when the () or () functions are used. Suffixes are added to the representation after negative signs.

]]> The range descriptor defines the ranges over which the counter style is defined. If a counter style is used to represent a counter value outside of its ranges, the counter style instead drops down to its fallback counter style.

]]> If the value of the fallback descriptor isn’t the name of any currently-defined counter style, the used value of the fallback descriptor is decimal instead. Similarly, while following fallbacks to find a counter style that can render the given counter value, if a loop in the specified fallbacks is detected, the decimal style must be used instead.

]]> The and additive-symbols descriptors specify the symbols used by the marker-construction algorithm specified by the descriptor. The descriptor must be specified if the counter system is cyclic, numeric, alphabetic, symbolic, or fixed, and the additive-symbols descriptor must be specified if the counter system is additive; otherwise, the @counter-style is invalid and must be ignored.

]]> The speak-as descriptor describes how to synthesize the spoken form of a counter formatted with the given counter style.

]]> The symbols() function allows a counter style to be defined inline in a property value, for when a style is used only once in a stylesheet and defining a full @counter-style rule would be overkill. It does not provide the full feature-set of the @counter-style rule, but provides a sufficient subset to still be useful.

]]>