CSS Counter Styles Level 3

Shortname: css-counter-styles
Level: 3
Status: CR
Work Status: Testing
Group: csswg
ED: http://dev.w3.org/csswg/css-counter-styles/
TR: http://www.w3.org/TR/css-counter-styles-3/
Previous Version: http://www.w3.org/TR/2014/WD-css-counter-styles-3-20140826/
Previous Version: http://www.w3.org/TR/2013/WD-css-counter-styles-3-20130718/
Previous Version: http://www.w3.org/TR/2013/WD-css-counter-styles-3-20130221/
Previous Version: http://www.w3.org/TR/2012/WD-css-counter-styles-3-20121009/
Editor: Tab Atkins Jr., Google, http://xanthir.com/contact/
Abstract: This module introduces the ''@counter-style'' rule, which allows authors to define their own custom counter styles for use with CSS list-marker and generated-content counters [[CSS3LIST]]. It also predefines a set of common counter styles, including the ones present in CSS2 and CSS2.1.
Issue Tracking: Bugzilla https://www.w3.org/Bugs/Public/buglist.cgi?product=CSS&component=Counter%20Styles&resolution=---
Link Defaults: css-text-3 (dfn) grapheme cluster, css-pseudo-4 (selector) ::marker, dom-ls (dfn) ascii case-insensitive
Deadline: 2015-05-03

Introduction

CSS 1 defined a handful of useful counter styles based on the styles that HTML traditionally allowed on ordered and unordered lists. While this was expanded slightly by CSS2.1, it doesn't address the needs of worldwide typography. This module introduces the ''@counter-style'' rule which allows CSS to address this in an open-ended manner, by allowing the author to define their own counter styles. These styles can then be used in the 'list-style-type' property or in the ''counter()'' and ''counters()'' functions. It also defines some additional predefined counter styles, particularly ones which are common but complicated to represent with ''@counter-style''.

Counter Styles

A counter style defines how to convert a counter value into a string. Counter styles are composed of: When asked to generate a counter representation using a particular counter style for a particular counter value, follow these steps:
  1. If the counter style is unknown, exit this algorithm and instead generate a counter representation using the ''decimal'' style and the same counter value.
  2. If the counter value is outside the 'range' of the counter style, exit this algorithm and instead generate a counter representation using the counter style's fallback style and the same counter value.
  3. Using the counter value and the counter algorithm for the counter style, generate an initial representation for the counter value. If the counter value is negative and the counter style uses a negative sign, instead generate an initial representation using the absolute value of the counter value.
  4. Prepend symbols to the representation as specified in the 'pad' descriptor.
  5. If the counter value is negative and the counter style uses a negative sign, wrap the representation in the counter style's negative sign as specified in the 'negative' descriptor.
  6. Return the representation.
Note: the prefix and suffix don't play a part in this algorithm. This is intentional; the prefix and suffix aren't part of the string returned by the counter() or counters() functions. Instead, the prefix and suffix are added by the algorithm that constructs the value of the 'content' property for the ''::marker'' pseudo-element. This also implies that the prefix and suffix always come from the specified counter-style, even if the actual representation is constructed by a fallback style. Some values of 'system' (''symbolic'', ''additive'') and some descriptors ('pad') can generate representations with size linear to an author-supplied number. This can potentially be abused to generate excessively large representations and consume undue amounts of the user's memory or even hang their browser. User agents must support representations at least 60 Unicode codepoints long, but they may choose to instead use the fallback style for representations that would be longer than 60 codepoints.

Defining Custom Counter Styles: the ''@counter-style'' rule

The @counter-style rule allows authors to define a custom counter style. The components of a counter style are specified by descriptors in the ''@counter-style'' rule. The algorithm is specified implicitly by a combination of the ''system'', ''symbols'', and ''additive-symbols'' properties. The general form of an ''@counter-style'' rule is:
@counter-style <> { <> }
where <counter-style-name> is a <>. If a counter style's name is an ASCII case-insensitive match for "decimal" or "none", the ''@counter-style'' rule is invalid. Note: Note that <> also automatically excludes the CSS-wide keywords. In addition, some names, like ''inside'', are valid as counter style names, but conflict with the existing values of properties like 'list-style', and so won't be usable there. Counter style names are case-sensitive. However, the names defined in this specification are ASCII lower-cased on parse wherever they are used as counter styles, e.g. in the 'list-style' set of properties, in the ''@counter-style'' rule, and in the ''counter()'' functions. Each ''@counter-style'' rule specifies a value for every counter-style descriptor, either implicitly or explicitly. Those not given explicit value in the rule take the initial value listed with each descriptor in this specification. These descriptors apply solely within the context of the ''@counter-style'' rule in which they are defined, and do not apply to document language elements. There is no notion of which elements the descriptors apply to or whether the values are inherited by child elements. When a given descriptor occurs multiple times in a given ''@counter-style'' rule, only the last specified value is used; all prior values for that descriptor must be ignored. Defining a ''@counter-style'' makes it available to the entire document in which it is included. If multiple ''@counter-style'' rules are defined with the same name, only one wins, according to standard cascade rules. ''@counter-style'' rules cascade "atomically": if one replaces another of the same name, it replaces it entirely, rather than just replacing the specific descriptors it specifies. Note: Note that even the predefined counter styles can be overridden; the UA stylesheet occurs before any other stylesheets, so the predefined ones always lose in the cascade. This at-rule conforms with the forward-compatible parsing requirement of CSS; conformant parsers that don't understand these rules will ignore them without error. Any descriptors that are not recognized or implemented by a given user agent, or whose value does not match the grammars given here or in a future version of this specification, must be ignored in their entirety; they do not make the ''@counter-style'' rule invalid.

Counter algorithms: the 'system' descriptor

	Name: system
	For: @counter-style
	Value: cyclic | numeric | alphabetic | symbolic | additive | [fixed <>?] | [ extends <> ]
	Initial: symbolic
	
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 systems are defined as follows:

Cycling Symbols: the ''cyclic'' system

The cyclic counter system cycles repeatedly through its provided symbols, looping back to the beginning when it reaches the end of the list. It can be used for simple bullets (just provide a single counter symbol), or for cycling through multiple symbols. The first counter symbol is used as the representation of the value 1, the second counter symbol (if it exists) is used as the representation of the value 2, etc. If the system is ''cyclic'', the 'symbols' descriptor must contain at least one counter symbol, or else the ''@counter-style'' rule is invalid. This system is defined over all counter values.
A "triangle bullet" counter style can be defined as:
		@counter-style triangle {
			system: cyclic;
			symbols: ‣;
			suffix: " ";
		}
		
It will then produce lists that look like:
		‣  One
		‣  Two
		‣  Three
		
If there are N counter symbols and a representation is being constructed for the integer value, the representation is the counter symbol at index ( (value-1) mod N) of the list of counter symbols (0-indexed).

Exhaustible Symbols: the ''fixed'' system

The fixed counter system runs through its list of counter symbols once, then falls back. It is useful for representing counter styles that only have a finite number of representations. For example, Unicode defines several limited-length runs of special characters meant for lists, such as circled digits. If the system is ''fixed'', the 'symbols' descriptor must contain at least one counter symbol, or else the ''@counter-style'' rule is invalid. This system is defined over counter values in a finite range, starting with the first symbol value and having a length equal to the length of the list of counter symbols. When this system is specified, it may optionally have an integer provided after it, which sets the first symbol value. If it is omitted, the first symbol value is 1.
A "box-corner" counter style can be defined as:
		@counter-style box-corner {
			system: fixed;
			symbols: ◰ ◳ ◲ ◱;
			suffix: ': ';
		}
		
It will then produce lists that look like:
		◰:  One
		◳:  Two
		◲:  Three
		◱:  Four
		5:  Five
		6:  Six
		
The first counter symbol is the representation for the first symbol value, and subsequent counter values are represented by subsequent counter symbols. Once the list of counter symbols is exhausted, further values cannot be represented by this counter style, and must instead be represented by the fallback counter style.

Repeating Symbols: the ''symbolic'' system

The symbolic counter system cycles repeatedly through its provided symbols, doubling, tripling, etc. the symbols on each successive pass through the list. For example, if the original symbols were "*" and "†", then on the second pass they would instead be "**" and "††", while on the third they would be "***"and "†††", etc. It can be used for footnote-style markers, and is also sometimes used for alphabetic-style lists for a slightly different presentation than what the alphabetic system presents. If the system is ''symbolic'', the 'symbols' descriptor must contain at least one counter symbol, or else the ''@counter-style'' rule is invalid. This system is defined only over strictly positive counter values.
An "footnote" counter style can be defined as:
		@counter-style footnote {
			system: symbolic;
			symbols: '*' ⁑ † ‡;
			suffix: " ";
		}
		
It will then produce lists that look like:
		*   One
		⁑   Two
		†   Three
		‡   Four
		**  Five
		⁑⁑  Six
		
Some style guides mandate a list numbering that looks similar to ''upper-alpha'', but repeats differently after the first 26 values, instead going "AA", "BB", "CC", etc. This can be achieved with the symbolic system:
		@counter-style upper-alpha-legal {
			system: symbolic;
			symbols: A B C D E F G H I J K L M
			         N O P Q R S T U V W X Y Z;
		}
		
This style is identical to ''upper-alpha'' through the first 27 values, but they diverge after that, with ''upper-alpha'' going "AB", "AC", "AD", etc. Starting at the 53rd value, ''upper-alpha'' goes "BA", "BB", "BC", etc., while this style jumps into triple digits with "AAA", "BBB", "CCC", etc.
To construct the representation, run the following algorithm: Let N be the length of the list of counter symbols, value initially be the counter value, S initially be the empty string, and symbol(n) be the nth counter symbol in the list of counter symbols (0-indexed).
  1. Let the chosen symbol be symbol( (value - 1) mod N).
  2. Let the representation length be ceil( value / N ).
  3. Append the chosen symbol to S a number of times equal to the representation length.
Finally, return S.

Bijective Numerals: the ''alphabetic'' system

The alphabetic counter system interprets the list of counter symbols as digits to an alphabetic numbering system, similar to the default ''lower-alpha'' counter style, which wraps from "a", "b", "c", to "aa", "ab", "ac". Alphabetic numbering systems do not contain a digit representing 0; so the first value when a new digit is added is composed solely of the first digit. Alphabetic numbering systems are commonly used for lists, and also appear in many spreadsheet programs to number columns. The first counter symbol in the list is interpreted as the digit 1, the second as the digit 2, and so on. If the system is alphabetic, the 'symbols' descriptor must contain at least two counter symbols, or else the ''@counter-style'' rule is invalid. This system is defined only over strictly positive counter values.
A counter style using go stones can be defined as:
		@counter-style go {
			system: alphabetic;
			symbols: url(white.svg) url(black.svg);
			suffix: " ";
		}
		
It will then produce lists that look like:
One
Two
Three
Four
Five
Six
Seven
Note: This example requires support for SVG images to display correctly.
If there are N counter symbols, the representation is a base N alphabetic number using the counter symbols as digits. To construct the representation, run the following algorithm: Let N be the length of the list of counter symbols, value initially be the counter value, S initially be the empty string, and symbol(n) be the nth counter symbol in the list of counter symbols (0-indexed). While value is not equal to 0:
  1. Set value to value - 1.
  2. Prepend symbol( value mod N ) to S.
  3. Set value to floor( value / N ).
Finally, return S.

Positional Numerals: the ''numeric'' system

The numeric counter system interprets the list of counter symbols as digits to a "place-value" numbering system, similar to the default ''decimal'' counter style. The first counter symbol in the list is interpreted as the digit 0, the second as the digit 1, and so on. If the system is numeric, the 'symbols' descriptor must contain at least two counter symbols, or else the ''@counter-style'' rule is invalid. This system is defined over all counter values.
A "trinary" counter style can be defined as:
		@counter-style trinary {
			system: numeric;
			symbols: '0' '1' '2';
		}
		
It will then produce lists that look like:
		1.   One
		2.   Two
		10.  Three
		11.  Four
		12.  Five
		20.  Six
		
If there are N counter symbols, the representation is a base N number using the counter symbols as digits. To construct the representation, run the following algorithm: Let N be the length of the list of counter symbols, value initially be the counter value, S initially be the empty string, and symbol(n) be the nth counter symbol in the list of counter symbols (0-indexed).
  1. If value is 0, append symbol(0) to S and return S.
  2. While value is not equal to 0:
    1. Prepend symbol( value mod N ) to S.
    2. Set value to floor( value / N ).
  3. Return S.

Accumulating Numerals: the ''additive'' system

The additive counter system is used to represent "sign-value" numbering systems, which, rather than using reusing digits in different positions to change their value, define additional digits with much larger values, so that the value of the number can be obtained by adding all the digits together. This is used in Roman numerals and other numbering systems around the world. If the system is ''additive'', the 'additive-symbols' descriptor must contain at least one additive tuple, or else the ''@counter-style'' rule is invalid. This system is nominally defined over all counter values (see algorithm, below, for exact details).
A "dice" counter style can be defined as:
		@counter-style dice {
			system: additive;
			additive-symbols: 6 ⚅, 5 ⚄, 4 ⚃, 3 ⚂, 2 ⚁, 1 ⚀;
			suffix: " ";
		}
		
It will then produce lists that look like:
		  ⚀  One
		  ⚁  Two
		  ⚂  Three
		...
		 ⚅⚄  Eleven
		 ⚅⚅  Twelve
		⚅⚅⚀  Thirteen
		
To construct the representation, run this algorithm: Let value initially be the counter value, S initially be the empty string, and symbol list initially be the list of additive tuples.
  1. If value is initially 0, and there is an additive tuple with a weight of 0, append that tuple's counter symbol to S and return S.
  2. While value is greater than 0 and there are elements left in the symbol list:
    1. Pop the first additive tuple from the symbol list. This is the current tuple.
    2. Append the current tuple’s counter symbol to S floor( value / current tuple’s weight ) times (this may be 0).
    3. Decrement value by the current tuple’s weight multiplied by the number of times the current tuple was appended to S in the previous step.
  3. If the loop ended because value is 0, return S. Otherwise, the given counter value cannot be represented by this counter style, and must instead be represented by the fallback counter style.
Note: All of the predefined additive ''@counter-style'' rules in this specification produce representations for every value in their range, but it's possible to produce values for ''additive-symbols'' that will fail to find a representation with the algorithm defined above, even though theoretically a representation could be found. For example, if a ''@counter-style'' was defined with ''additive-symbols: 3 "a", 2 "b";'', the algorithm defined above will fail to find a representation for a counter value of 4, even though theoretically a "bb" representation would work. While unfortunate, this is required to maintain the property that the algorithm runs in linear time relative to the size of the counter value.

Building from Existing Counter Styles: the ''extends'' system

The extends system allows an author to use the algorithm of another counter style, but alter other aspects, such as the negative sign or the suffix. If a counter style uses the ''extends'' system, any unspecified descriptors must be taken from the extended counter style specified, rather than taking their initial values. If a @counter-style uses the ''extends'' system, it must not contain a 'symbols' or 'additive-symbols' descriptor, or else the ''@counter-style'' rule is invalid. If the specified counter style name isn't the name of any currently-defined counter style, it must be treated as if it was extending the ''decimal'' counter style. If one or more ''@counter-style'' rules form a cycle with their ''extends'' values, all of the counter styles participating in the cycle must be treated as if they were extending the ''decimal'' counter style instead.
For example, if you wanted a counter style that was identical to decimal, but used a parenthesis rather than a period after it, like:
		1) first item
		2) second item
		3) third item
		
Rather than writing up an entirely new counter style, this can be done by just extending ''decimal'':
		@counter-style decimal-paren {
			system: extends decimal;
			suffix: ") ";
		}
		

Formatting negative values: the 'negative' descriptor

	Name: negative
	For: @counter-style
	Value: <> <>?
	Initial: "\2D" ("-" hyphen-minus)
	
The 'negative' descriptor defines how to alter the representation when the counter value is negative. The first <> in the value is prepended to the representation when the counter value is negative. The second <>, if specified, is appended to the representation when the counter value is negative.
For example, specifying ''negative: "(" ")";'' will make negative values be wrapped in parentheses, which is sometimes used in financial contexts, like "(2) (1) 0 1 2 3...".
Not all 'system' values use a negative sign. In particular, a counter style uses a negative sign if its 'system' value is ''symbolic'', ''system/alphabetic'', ''system/numeric'', ''additive'', or ''extends'' if the extended counter style itself uses a negative sign. If a counter style does not use a negative sign, it ignores the negative sign when generating a counter representation.

Symbols before the marker: the 'prefix' descriptor

	Name: prefix
	For: @counter-style
	Value: <>
	Initial: "" (the empty string)
	
The 'prefix' descriptor specifies a <> that is prepended to the marker representation. Prefixes are only added by the algorithm for constructing the default contents of the ''::marker'' pseudo-element; the prefix is not added automatically when the counter() or counters() functions are used. Prefixes come before any negative sign.

Symbols after the marker: the 'suffix' descriptor

	Name: suffix
	For: @counter-style
	Value: <>
	Initial: "\2E\20" ("." full stop followed by a space)
	
The 'suffix' descriptor specifies a <> 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 counter() or counters() functions are used. Suffixes are added to the representation after negative signs.

Limiting the counter scope: the 'range' descriptor

	Name: range
	For: @counter-style
	Value: [ [ <> | infinite ]{2} ]# | auto
	Initial: auto
	
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.
auto
The range depends on the counter system:
  • For ''cyclic'', numeric, and ''fixed'' systems, the range is negative infinity to positive infinity.
  • For alphabetic and ''symbolic'' systems, the range is 1 to positive infinity.
  • For ''additive'' systems, the range is 0 to positive infinity.
  • For ''extends'' systems, the range is whatever ''range/auto'' would produce for the extended system; if extending a complex predefined style (), the range is the style's defined range.
[ [ <> | infinite ]{2} ]#
This defines a comma-separated list of ranges. For each individual range, the first value is the lower bound and the second value is the upper bound. This range is inclusive - it contains both the lower and upper bound numbers. If ''infinite'' is used as the first value in a range, it represents negative infinity; if used as the second value, it represents positive infinity. The range of the counter style is the union of all the ranges defined in the list. If the lower bound of any range is higher than the upper bound, the entire descriptor is invalid and must be ignored.
Implementations must support ranges with a lower bound of at least -215 and an upper bound of at least 215-1 (the range of a signed 2-byte int). They may support higher ranges. If any specified bound is outside of the implementation's supported bounds, it must be treated as the closest bound that the implementation does support.

Zero-Padding and Constant-Width Representations: the 'pad' descriptor

	Name: pad
	For: @counter-style
	Value: <> && <>
	Initial: 0 ""
	
The 'pad' descriptor allows an author to specify a "fixed-width" counter style, where representations shorter than the pad value are padded with a particular <>. Representations larger than the specified pad value are constructed as normal.
<> && <>
The <> specifies a minimum length that all counter representations must reach. Let difference be the provided <> minus the number of grapheme clusters in the initial representation for the counter value. (Note that, per the algorithm to generate a counter representation, this occurs before adding prefixes/suffixes/negatives.) If the counter value is negative and the counter style uses a negative sign, further reduce difference by the number of grapheme clusters in the counter style’s 'negative' descriptor’s <>(s). If difference is greater than zero, prepend difference copies of the specified <> to the representation. The <> must be non-negative. A negative value is a syntax error.
The most common example of "fixed-width" numbering is zero-padded decimal numbering. If an author knows that the numbers used will be less than a thousand, for example, it can be zero-padded with a simple ''pad: 3 "0";'' descriptor, ensuring that all of the representations are 3 digits wide. This will cause, for example, 1 to be represented as "001", 20 to be represented as "020", 300 to be represented as "300", 4000 to be represented as "4000", and -5 to be represented as "-05".
Note: The 'pad' descriptor counts the number of grapheme clusters in the representation, but pads it with <>s. If the specified 'pad' <> is multi-character, this will likely not have the desired effect. Unfortunately, there's no way to use the number of grapheme clusters in the 'pad' <> without violating useful constraints. It is recommended that authors only specify <>s of a single grapheme cluster in the 'pad' descriptor.

Defining fallback: the 'fallback' descriptor

	Name: fallback
	For: @counter-style
	Value: <>
	Initial: decimal
	
The 'fallback' descriptor specifies a fallback counter style to be used when the current counter style can't create a representation for a given counter value. For example, if a counter style defined with a range of 1-10 is asked to represent a counter value of 11, the counter value's representation is instead constructed with the fallback counter style (or possibly the fallback style's fallback style, if the fallback style can't represent that value, etc.). 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.

Note that it is not necessarily an error to specify fallback loops. For example, if an author desires a counter style with significantly different representations for even and odd counter values, they may find it easiest to define one style that can only represent odd values and one that can only represent even values, and specify each as the fallback for the other one. Though the fallback graph is circular, at no point do you encounter a loop while following these fallbacks - every counter value is represented by one or the other counter style.

Marker characters: the 'symbols' and 'additive-symbols' descriptors

	Name: symbols
	For: @counter-style
	Value: <>+
	Initial: n/a
	
	Name: additive-symbols
	For: @counter-style
	Value: [ <> && <> ]#
	Initial: n/a
	
<symbol> = <> | <> | <>
The 'symbols' and 'additive-symbols' descriptors specify the symbols used by the marker-construction algorithm specified by the 'system' descriptor. The 'symbols' 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. Some counter systems specify that the 'symbols' descriptor must have at least two entries. If the counter style's system is such, and the 'symbols' descriptor has only a single entry, the counter style is invalid and must be ignored. Each entry in the 'symbols' descriptor's value defines a counter symbol, which is interpreted differently based on the counter style's system. Each entry in the 'additive-symbols' descriptor's value defines an additive tuple, which consists of a counter symbol and a non-negative integer weight. Each weight must be a non-negative integer, and the additive tuples must be specified in order of descending weight; otherwise, the @counter-style is invalid and must be ignored. Counter symbols may be strings, images, or identifiers, and the three types can be mixed in a single descriptor. Counter representations are constructed by concatenating counter symbols together. Identifiers are rendered as strings containing the same characters. Images are rendered as inline replaced elements. The default object size of an image counter symbol is a 1em by 1em square. Note: If using identifiers rather than strings to define the symbols, be aware of the syntax of identifiers. In particular, ascii non-letters like "*" are not identifiers, and so must be quoted in a string. Hex escapes, used in several of the counter styles defined in this specification, "eat" the following space (to allow a digit to follow a hex escape without ambiguity), so two spaces must be put after a hex escape to separate it from the following one, or else they'll be considered adjacent, and part of the same identifier.

Speech Synthesis: the 'speak-as' descriptor

	Name: speak-as
	For: @counter-style
	Value: auto | bullets | numbers | words | spell-out | <>
	Initial: auto
	
A counter style can be constructed with a meaning that is obvious visually, but impossible to meaningfully represent via a speech synthesizer, or possible but nonsensical when naively read out. The 'speak-as' descriptor describes how to synthesize the spoken form of a counter formatted with the given counter style. Values have the following meanings:
auto
If the counter style's 'system' is ''alphabetic'', this value has the same effect as ''spell-out''. If the 'system' is ''cyclic'', this value has the same effect as ''bullets''. If the 'system' is ''extends'', this value has the same effect as ''speak-as/auto'' would have for the extended style. Otherwise, this value has the same effect as ''numbers''.
bullets
The UA speaks a UA-defined phrase or audio cue that represents an unordered list item being read out.
numbers
The counter's value is spoken as a number in the document language.
words
Generate a counter representation for the value as normal, then speak it as normal text in the document language.
spell-out
Generate a counter representation for the value as normal, then spell it out letter-by-letter in the document language. If the UA does not know how to pronounce the symbols, it may handle it as ''numbers''. For example, ''lower-greek'' in English would be read out as "alpha", "beta", "gamma", etc. Conversely, ''upper-latin'' in French would be read out as (in phonetic notation) /a/, /be/, /se/, etc.
<>
The counter's value is instead spoken out in the specified style (similar to the behavior of the 'fallback' descriptor when generating representations for a counter value). If the specified style does not exist, this value is treated as ''speak-as/auto''. If a loop is detected when following 'speak-as' references, this value is treated as ''speak-as/auto'' for the counter styles participating in the loop.
The ability to defer pronunciation to another counter style can help when the symbols being used aren't actually letters. For example, here's a possible definition of a ''circled-lower-latin'' counter-style, using some special unicode characters:
		@counter-style circled-lower-latin {
		  system: alphabetic;
		  speak-as: lower-latin;
		  symbols: ⓐ ⓑ ⓒ ⓓ ⓔ ⓕ ⓖ ⓗ ⓘ ⓙ ⓚ ⓛ ⓜ ⓝ ⓞ ⓟ ⓠ ⓡ ⓢ ⓣ ⓤ ⓥ ⓦ ⓧ ⓨ ⓩ;
		  suffix: " ";
		}
		
Setting its 'system' to alphabetic would normally make the UA try to read out the names of the characters, but in this case that might be something like "Circled Letter A", which is unlikely to make sense. Instead, explicitly setting 'speak-as' to ''lower-latin'' ensures that they get read out as their corresponding latin letters, as intended.

Defining Anonymous Counter Styles: the ''symbols()'' function

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. The syntax of the ''symbols()'' rule is:
		symbols() = symbols( <>? [ <> | <> ]+ );
		<symbols-type> = cyclic | numeric | alphabetic | symbolic | fixed;
	
The ''symbols()'' function defines an anonymous counter style with no name, a 'prefix' of ''""'' (empty string) and 'suffix' of ''" "'' (U+0020 SPACE), a 'range' of auto, a 'fallback' of ''decimal'', a 'negative' of ''"\2D"'' ("-" hyphen-minus), a 'pad' of ''0 ""'', and a 'speak-as' of ''speak-as/auto''. The counter style's algorithm is constructed by consulting the previous chapter using the provided system — or ''symbolic'' if the system was omitted — and the provided <>s and <>s as the value of the 'symbols' property. If the system is ''fixed'', the first symbol value is ''1''. If the system is ''system/alphabetic'' or ''system/numeric'', there must be at least two <>s or <>s, or else the function is invalid.
This code:
ol { list-style: symbols("*" "\2020" "\2021" "\A7"); }
will produce lists that look like:
		*   One
		†   Two
		‡   Three
		§   Four
		**  Five
		††  Six
		‡‡  Seven
		
On the other hand, specifying the system of counter, like so:
ol { list-style: symbols(cyclic "*" "\2020" "\2021" "\A7"); }
will produce lists that look like:
		*   One
		†   Two
		‡   Three
		§   Four
		*   Five
		†   Six
		‡   Seven
		
Note: the ''symbols()'' function only allows strings and images, while the 'symbols' descriptor of a ''@counter-style'' rule also allows identifiers.

Extending 'list-style-type', ''counter()'', and ''counters()''

In CSS Level 2 [[!CSS21]] the 'list-style-type' property and the ''counter()'' and ''counters()'' notations accept various pre-defined keywords, each identifying a counter style. This module extends these features to take instead the <> type, defined below:
		<counter-style> = <> | symbols();
	
If a <> is used that does not refer to any existing counter style, it must act identically to the ''decimal'' counter style.

Simple Predefined Counter Styles

The following stylesheet uses the ''@counter-style'' rule to redefine all of the counter styles defined in CSS 2 and CSS 2.1. This stylesheet is normative-- UAs must include it in their UA stylesheet (or at least act as if these rules were defined at that level).

Numeric: ''decimal'', ''decimal-leading-zero'', ''arabic-indic'', ''armenian'', ''upper-armenian'', ''lower-armenian'', ''bengali'', ''cambodian'', ''khmer'', ''cjk-decimal'', ''devanagari'', ''georgian'', ''gujarati'', ''gurmukhi'', ''hebrew'', ''kannada'', ''lao'', ''malayalam'', ''mongolian'', ''myanmar'', ''oriya'', ''persian'', ''lower-roman'', ''upper-roman'', ''tamil'', ''telugu'', ''thai'', ''tibetan''

decimal
Western decimal numbers (e.g., 1, 2, 3, ..., 98, 99, 100).
decimal-leading-zero
Decimal numbers padded by initial zeros (e.g., 01, 02, 03, ..., 98, 99, 100).
arabic-indic
Arabic-indic numbering (e.g., ١‎, ٢‎, ٣‎, ٤‎, ..., ٩٨‎, ٩٩‎, ١٠٠‎).
armenian
upper-armenian
Traditional uppercase Armenian numbering (e.g., Ա, Բ, Գ, ..., ՂԸ, ՂԹ, Ճ).
lower-armenian
Lowercase Armenian numbering (e.g., ա, բ, գ, ..., ղը, ղթ, ճ).
bengali
Bengali numbering (e.g., ১, ২, ৩, ..., ৯৮, ৯৯, ১০০).
cambodian
khmer
Cambodian/Khmer numbering (e.g., ១, ២, ៣, ..., ៩៨, ៩៩, ១០០).
cjk-decimal
Han decimal numbers (e.g., 一, 二, 三, ..., 九八, 九九, 一〇〇).
devanagari
devanagari numbering (e.g., १, २, ३, ..., ९८, ९९, १००).
georgian
Traditional Georgian numbering (e.g., ა, ბ, გ, ..., ჟჱ, ჟთ, რ).
gujarati
Gujarati numbering (e.g., ૧, ૨, ૩, ..., ૯૮, ૯૯, ૧૦૦).
gurmukhi
Gurmukhi numbering (e.g., ੧, ੨, ੩, ..., ੯੮, ੯੯, ੧੦੦).
hebrew
Traditional Hebrew numbering (e.g., א‎, ב‎, ג‎, ..., צח‎, צט‎, ק‎).
kannada
Kannada numbering (e.g., ೧, ೨, ೩, ..., ೯೮, ೯೯, ೧೦೦).
lao
Laotian numbering (e.g., ໑, ໒, ໓, ..., ໙໘, ໙໙, ໑໐໐).
malayalam
Malayalam numbering (e.g., ൧, ൨, ൩, ..., ൯൮, ൯൯, ൧൦൦).
mongolian
Mongolian numbering (e.g., ᠑, ᠒, ᠓, ..., ᠙᠘, ᠙᠙, ᠑᠐᠐).
myanmar
Myanmar (Burmese) numbering (e.g., ၁, ၂, ၃, ..., ၉၈, ၉၉, ၁၀၀).
oriya
Oriya numbering (e.g., ୧, ୨, ୩, ..., ୯୮, ୯୯, ୧୦୦).
persian
Persian numbering (e.g., ۱, ۲, ۳, ۴, ..., ۹۸, ۹۹, ۱۰۰).
lower-roman
Lowercase ASCII Roman numerals (e.g., i, ii, iii, ..., xcviii, xcix, c).
upper-roman
Uppercase ASCII Roman numerals (e.g., I, II, III, ..., XCVIII, XCIX, C).
tamil
Tamil numbering (e.g., ௧, ௨, ௩, ..., ௯௮, ௯௯, ௧௦௦).
telugu
Telugu numbering (e.g., ౧, ౨, ౩, ..., ౯౮, ౯౯, ౧౦౦).
thai
Thai (Siamese) numbering (e.g., ๑, ๒, ๓, ..., ๙๘, ๙๙, ๑๐๐).
tibetan
Tibetan numbering (e.g., ༡, ༢, ༣, ..., ༩༨, ༩༩, ༡༠༠).
The ''decimal'' counter-style must not be overridable with a ''@counter-style'' rule, so that it is always available as an ultimate fallback style. The following stylesheet fragment provides the normative definition of these predefined counter styles:

	@counter-style decimal {
		system: numeric;
		symbols: '0' '1' '2' '3' '4' '5' '6' '7' '8' '9';
	}

	@counter-style decimal-leading-zero {
		system: extends decimal;
		pad: 2 '0';
	}

	@counter-style arabic-indic {
		system: numeric;
		symbols: "\660" "\661" "\662" "\663" "\664" "\665" "\666" "\667" "\668" "\669";
		/* ٠ ١ ٢ ٣ ٤ ٥ ٦ ٧ ٨ ٩ */
	}

	@counter-style armenian {
		system: additive;
		range: 1 9999;
		additive-symbols: 9000 \554, 8000 \553, 7000 \552, 6000 \551, 5000 \550, 4000 \54F, 3000 \54E, 2000 \54D, 1000 \54C, 900 \54B, 800 \54A, 700 \549, 600 \548, 500 \547, 400 \546, 300 \545, 200 \544, 100 \543, 90 \542, 80 \541, 70 \540, 60 \53F, 50 \53E, 40 \53D, 30 \53C, 20 \53B, 10 \53A, 9 \539, 8 \538, 7 \537, 6 \536, 5 \535, 4 \534, 3 \533, 2 \532, 1 \531;
		/* 9000 Ք, 8000 Փ, 7000 Ւ, 6000 Ց, 5000 Ր, 4000 Տ, 3000 Վ, 2000 Ս, 1000 Ռ, 900 Ջ, 800 Պ, 700 Չ, 600 Ո, 500 Շ, 400 Ն, 300 Յ, 200 Մ, 100 Ճ, 90 Ղ, 80 Ձ, 70 Հ, 60 Կ, 50 Ծ, 40 Խ, 30 Լ, 20 Ի, 10 Ժ, 9 Թ, 8 Ը, 7 Է, 6 Զ, 5 Ե, 4 Դ, 3 Գ, 2 Բ, 1 Ա */
	}

	@counter-style upper-armenian {
		system: extends armenian;
	}

	@counter-style lower-armenian {
		system: additive;
		range: 1 9999;
		additive-symbols: 9000 "\584", 8000 "\583", 7000 "\582", 6000 "\581", 5000 "\580", 4000 "\57F", 3000 "\57E", 2000 "\57D", 1000 "\57C", 900 "\57B", 800 "\57A", 700 "\579", 600 "\578", 500 "\577", 400 "\576", 300 "\575", 200 "\574", 100 "\573", 90 "\572", 80 "\571", 70 "\570", 60 "\56F", 50 "\56E", 40 "\56D", 30 "\56C", 20 "\56B", 10 "\56A", 9 "\569", 8 "\568", 7 "\567", 6 "\566", 5 "\565", 4 "\564", 3 "\563", 2 "\562", 1 "\561";
		/* 9000 ք, 8000 փ, 7000 ւ, 6000 ց, 5000 ր, 4000 տ, 3000 վ, 2000 ս, 1000 ռ, 900 ջ, 800 պ, 700 չ, 600 ո, 500 շ, 400 ն, 300 յ, 200 մ, 100 ճ, 90 ղ, 80 ձ, 70 հ, 60 կ, 50 ծ, 40 խ, 30 լ, 20 ի, 10 ժ, 9 թ, 8 ը, 7 է, 6 զ, 5 ե, 4 դ, 3 գ, 2 բ, 1 ա */
	}

	@counter-style bengali {
		system: numeric;
		symbols: "\9E6" "\9E7" "\9E8" "\9E9" "\9EA" "\9EB" "\9EC" "\9ED" "\9EE" "\9EF";
		/* ০ ১ ২ ৩ ৪ ৫ ৬ ৭ ৮ ৯ */
	}

	@counter-style cambodian {
		system: numeric;
		symbols: "\17E0" "\17E1" "\17E2" "\17E3" "\17E4" "\17E5" "\17E6" "\17E7" "\17E8" "\17E9";
		/* ០ ១ ២ ៣ ៤ ៥ ៦ ៧ ៨ ៩ */
	}

	@counter-style khmer {
		system: extends cambodian;
	}

	@counter-style cjk-decimal {
		system: numeric;
		range: 0 infinite;
		symbols: \3007  \4E00  \4E8C  \4E09  \56DB  \4E94  \516D  \4E03  \516B  \4E5D;
		/* 〇 一 二 三 四 五 六 七 八 九 */
		suffix: "\3001";
		/* "、" */
	}

	@counter-style devanagari {
		system: numeric;
		symbols: "\966" "\967" "\968" "\969" "\96A" "\96B" "\96C" "\96D" "\96E" "\96F";
		/* ० १ २ ३ ४ ५ ६ ७ ८ ९ */
	}

	@counter-style georgian {
		system: additive;
		range: 1 19999;
		additive-symbols: 10000 \10F5, 9000 \10F0, 8000 \10EF, 7000 \10F4, 6000 \10EE, 5000 \10ED, 4000 \10EC, 3000 \10EB, 2000 \10EA, 1000 \10E9, 900 \10E8, 800 \10E7, 700 \10E6, 600 \10E5, 500 \10E4, 400 \10F3, 300 \10E2, 200 \10E1, 100 \10E0, 90 \10DF, 80 \10DE, 70 \10DD, 60 \10F2, 50 \10DC, 40 \10DB, 30 \10DA, 20 \10D9, 10 \10D8, 9 \10D7, 8 \10F1, 7 \10D6, 6 \10D5, 5 \10D4, 4 \10D3, 3 \10D2, 2 \10D1, 1 \10D0;
		/* 10000 ჵ, 9000 ჰ, 8000 ჯ, 7000 ჴ, 6000 ხ, 5000 ჭ, 4000 წ, 3000 ძ, 2000 ც, 1000 ჩ, 900 შ, 800 ყ, 700 ღ, 600 ქ, 500 ფ, 400 ჳ, 300 ტ, 200 ს, 100 რ, 90 ჟ, 80 პ, 70 ო, 60 ჲ, 50 ნ, 40 მ, 30 ლ, 20 კ, 10 ი, 9 თ, 8 ჱ, 7 ზ, 6 ვ, 5 ე, 4 დ, 3 გ, 2 ბ, 1 ა */
	}

	@counter-style gujarati {
		system: numeric;
		symbols: "\AE6" "\AE7" "\AE8" "\AE9" "\AEA" "\AEB" "\AEC" "\AED" "\AEE" "\AEF";
		/* ૦ ૧ ૨ ૩ ૪ ૫ ૬ ૭ ૮ ૯ */
	}

	@counter-style gurmukhi {
		system: numeric;
		symbols: "\A66" "\A67" "\A68" "\A69" "\A6A" "\A6B" "\A6C" "\A6D" "\A6E" "\A6F";
		/* ੦ ੧ ੨ ੩ ੪ ੫ ੬ ੭ ੮ ੯ */
	}

	@counter-style hebrew {
		system: additive;
		range: 1 10999;
		additive-symbols: 10000 \5D9\5F3, 9000 \5D8\5F3, 8000 \5D7\5F3, 7000 \5D6\5F3, 6000 \5D5\5F3, 5000 \5D4\5F3, 4000 \5D3\5F3, 3000 \5D2\5F3, 2000 \5D1\5F3, 1000 \5D0\5F3, 400 \5EA, 300 \5E9, 200 \5E8, 100 \5E7, 90 \5E6, 80 \5E4, 70 \5E2, 60 \5E1, 50 \5E0, 40 \5DE, 30 \5DC, 20 \5DB, 19 \5D9\5D8, 18 \5D9\5D7, 17 \5D9\5D6, 16 \5D8\5D6, 15 \5D8\5D5, 10 \5D9, 9 \5D8, 8 \5D7, 7 \5D6, 6 \5D5, 5 \5D4, 4 \5D3, 3 \5D2, 2 \5D1, 1 \5D0;
		/* 10000 י׳, 9000 ט׳, 8000 ח׳, 7000 ז׳, 6000 ו׳, 5000 ה׳, 4000 ד׳, 3000 ג׳, 2000 ב׳, 1000 א׳, 400 ת, 300 ש, 200 ר, 100 ק, 90 צ, 80 פ, 70 ע, 60 ס, 50 נ, 40 מ, 30 ל, 20 כ, 19 יט, 18 יח, 17 יז, 16 טז, 15 טו, 10 י, 9 ט, 8 ח, 7 ז, 6 ו, 5 ה, 4 ד, 3 ג, 2 ב, 1 א */
		/* This system manually specifies the values for 19-15 to force the correct display of 15 and 16, which are commonly rewritten to avoid a close resemblance to the Tetragrammaton. */
		/* Implementations MAY choose to implement this manually to a higher range; see note below. */
	}

	@counter-style kannada {
		system: numeric;
		symbols: "\CE6" "\CE7" "\CE8" "\CE9" "\CEA" "\CEB" "\CEC" "\CED" "\CEE" "\CEF";
		/* ೦ ೧ ೨ ೩ ೪ ೫ ೬ ೭ ೮ ೯ */
	}

	@counter-style lao {
		system: numeric;
		symbols: "\ED0" "\ED1" "\ED2" "\ED3" "\ED4" "\ED5" "\ED6" "\ED7" "\ED8" "\ED9";
		/* ໐ ໑ ໒ ໓ ໔ ໕ ໖ ໗ ໘ ໙ */
	}

	@counter-style malayalam {
		system: numeric;
		symbols: "\D66" "\D67" "\D68" "\D69" "\D6A" "\D6B" "\D6C" "\D6D" "\D6E" "\D6F";
		/* ൦ ൧ ൨ ൩ ൪ ൫ ൬ ൭ ൮ ൯ */
	}

	@counter-style mongolian {
		system: numeric;
		symbols: "\1810" "\1811" "\1812" "\1813" "\1814" "\1815" "\1816" "\1817" "\1818" "\1819";
		/* ᠐ ᠑ ᠒ ᠓ ᠔ ᠕ ᠖ ᠗ ᠘ ᠙ */
	}

	@counter-style myanmar {
		system: numeric;
		symbols: "\1040" "\1041" "\1042" "\1043" "\1044" "\1045" "\1046" "\1047" "\1048" "\1049";
		/* ၀ ၁ ၂ ၃ ၄ ၅ ၆ ၇ ၈ ၉ */
	}

	@counter-style oriya {
		system: numeric;
		symbols: "\B66" "\B67" "\B68" "\B69" "\B6A" "\B6B" "\B6C" "\B6D" "\B6E" "\B6F";
		/* ୦ ୧ ୨ ୩ ୪ ୫ ୬ ୭ ୮ ୯ */
	}

	@counter-style persian {
		system: numeric;
		symbols: "\6F0" "\6F1" "\6F2" "\6F3" "\6F4" "\6F5" "\6F6" "\6F7" "\6F8" "\6F9";
		/* ۰ ۱ ۲ ۳ ۴ ۵ ۶ ۷ ۸ ۹ */
	}

	@counter-style lower-roman {
		system: additive;
		range: 1 3999;
		additive-symbols: 1000 m, 900 cm, 500 d, 400 cd, 100 c, 90 xc, 50 l, 40 xl, 10 x, 9 ix, 5 v, 4 iv, 1 i;
	}

	@counter-style upper-roman {
		system: additive;
		range: 1 3999;
		additive-symbols: 1000 M, 900 CM, 500 D, 400 CD, 100 C, 90 XC, 50 L, 40 XL, 10 X, 9 IX, 5 V, 4 IV, 1 I;
	}

	@counter-style tamil {
		system: numeric;
		symbols: "\BE6" "\BE7" "\BE8" "\BE9" "\BEA" "\BEB" "\BEC" "\BED" "\BEE" "\BEF";
		/* ௦ ௧ ௨ ௩ ௪ ௫ ௬ ௭ ௮ ௯ */
	}

	@counter-style telugu {
		system: numeric;
		symbols: "\C66" "\C67" "\C68" "\C69" "\C6A" "\C6B" "\C6C" "\C6D" "\C6E" "\C6F";
		/* ౦ ౧ ౨ ౩ ౪ ౫ ౬ ౭ ౮ ౯ */
	}

	@counter-style thai {
		system: numeric;
		symbols: "\E50" "\E51" "\E52" "\E53" "\E54" "\E55" "\E56" "\E57" "\E58" "\E59";
		/* ๐ ๑ ๒ ๓ ๔ ๕ ๖ ๗ ๘ ๙ */
	}

	@counter-style tibetan {
		system: numeric;
		symbols: "\F20" "\F21" "\F22" "\F23" "\F24" "\F25" "\F26" "\F27" "\F28" "\F29";
		/* ༠ ༡ ༢ ༣ ༤ ༥ ༦ ༧ ༨ ༩ */
	}
	
Implementations must implement ''hebrew'' at least to the range specified in the ''@counter-style'' rule above, but may implement it to a higher range. If they do so, the corresponding 'range' descriptor must reflect the implemented range.

Alphabetic: ''lower-alpha'', ''lower-latin'', ''upper-alpha'', ''upper-latin'', ''cjk-earthly-branch'', ''cjk-heavenly-stem'', ''lower-greek'', ''hiragana'', ''hiragana-iroha'', ''katakana'', ''katakana-iroha''

lower-alpha
lower-latin
Lowercase ASCII letters (e.g., a, b, c, ..., z, aa, ab).
upper-alpha
upper-latin
Uppercase ASCII letters (e.g., A, B, C, ..., Z, AA, AB).
cjk-earthly-branch
Han "Earthly Branch" ordinals (e.g., 子, 丑, 寅, ..., 亥, 子子, 子丑).
cjk-heavenly-stem
Han "Heavenly Stem" ordinals (e.g., 甲, 乙, 丙, ..., 癸, 甲甲, 甲乙).
lower-greek
Lowercase classical Greek (e.g., α, β, γ, ..., ω, αα, αβ).
hiragana
Dictionary-order hiragana lettering (e.g., あ, い, う, ..., ん, ああ, あい).
hiragana-iroha
Iroha-order hiragana lettering (e.g., い, ろ, は, ..., す, いい, いろ).
katakana
Dictionary-order katakana lettering (e.g., ア, イ, ウ, ..., ン, アア, アイ).
katakana-iroha
Iroha-order katakana lettering (e.g., イ, ロ, ハ, ..., ス, イイ, イロ)
The following stylesheet fragment provides the normative definition of these predefined counter styles:

	@counter-style lower-alpha {
		system: alphabetic;
		symbols: a b c d e f g h i j k l m n o p q r s t u v w x y z;
	}

	@counter-style lower-latin {
		system: extends lower-alpha;
	}

	@counter-style upper-alpha {
		system: alphabetic;
		symbols: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z;
	}

	@counter-style upper-latin {
		system: extends upper-alpha;
	}

	@counter-style cjk-earthly-branch {
		system: alphabetic;
		symbols: "\5B50" "\4E11" "\5BC5" "\536F" "\8FB0" "\5DF3" "\5348" "\672A" "\7533" "\9149" "\620C" "\4EA5";
		/* 子 丑 寅 卯 辰 巳 午 未 申 酉 戌 亥 */
		suffix: "、";
	}

	@counter-style cjk-heavenly-stem {
		system: alphabetic;
		symbols: "\7532" "\4E59" "\4E19" "\4E01" "\620A" "\5DF1" "\5E9A" "\8F9B" "\58EC" "\7678";
		/* 甲 乙 丙 丁 戊 己 庚 辛 壬 癸 */
		suffix: "、";
	}

	@counter-style lower-greek {
		system: alphabetic;
		symbols: "\3B1" "\3B2" "\3B3" "\3B4" "\3B5" "\3B6" "\3B7" "\3B8" "\3B9" "\3BA" "\3BB" "\3BC" "\3BD" "\3BE" "\3BF" "\3C0" "\3C1" "\3C3" "\3C4" "\3C5" "\3C6" "\3C7" "\3C8" "\3C9";
		/* α β γ δ ε ζ η θ ι κ λ μ ν ξ ο π ρ σ τ υ φ χ ψ ω */
	}

	@counter-style hiragana {
		system: alphabetic;
		symbols: "\3042" "\3044" "\3046" "\3048" "\304A" "\304B" "\304D" "\304F" "\3051" "\3053" "\3055" "\3057" "\3059" "\305B" "\305D" "\305F" "\3061" "\3064" "\3066" "\3068" "\306A" "\306B" "\306C" "\306D" "\306E" "\306F" "\3072" "\3075" "\3078" "\307B" "\307E" "\307F" "\3080" "\3081" "\3082" "\3084" "\3086" "\3088" "\3089" "\308A" "\308B" "\308C" "\308D" "\308F" "\3090" "\3091" "\3092" "\3093";
		/* あ い う え お か き く け こ さ し す せ そ た ち つ て と な に ぬ ね の は ひ ふ へ ほ ま み む め も や ゆ よ ら り る れ ろ わ ゐ ゑ を ん */
		suffix: "、";
	}

	@counter-style hiragana-iroha {
		system: alphabetic;
		symbols: "\3044" "\308D" "\306F" "\306B" "\307B" "\3078" "\3068" "\3061" "\308A" "\306C" "\308B" "\3092" "\308F" "\304B" "\3088" "\305F" "\308C" "\305D" "\3064" "\306D" "\306A" "\3089" "\3080" "\3046" "\3090" "\306E" "\304A" "\304F" "\3084" "\307E" "\3051" "\3075" "\3053" "\3048" "\3066" "\3042" "\3055" "\304D" "\3086" "\3081" "\307F" "\3057" "\3091" "\3072" "\3082" "\305B" "\3059";
		/* い ろ は に ほ へ と ち り ぬ る を わ か よ た れ そ つ ね な ら む う ゐ の お く や ま け ふ こ え て あ さ き ゆ め み し ゑ ひ も せ す */
		suffix: "、";
	}

	@counter-style katakana {
		system: alphabetic;
		symbols: "\30A2" "\30A4" "\30A6" "\30A8" "\30AA" "\30AB" "\30AD" "\30AF" "\30B1" "\30B3" "\30B5" "\30B7" "\30B9" "\30BB" "\30BD" "\30BF" "\30C1" "\30C4" "\30C6" "\30C8" "\30CA" "\30CB" "\30CC" "\30CD" "\30CE" "\30CF" "\30D2" "\30D5" "\30D8" "\30DB" "\30DE" "\30DF" "\30E0" "\30E1" "\30E2" "\30E4" "\30E6" "\30E8" "\30E9" "\30EA" "\30EB" "\30EC" "\30ED" "\30EF" "\30F0" "\30F1" "\30F2" "\30F3";
		/* ア イ ウ エ オ カ キ ク ケ コ サ シ ス セ ソ タ チ ツ テ ト ナ ニ ヌ ネ ノ ハ ヒ フ ヘ ホ マ ミ ム メ モ ヤ ユ ヨ ラ リ ル レ ロ ワ ヰ ヱ ヲ ン */
		suffix: "、";
	}

	@counter-style katakana-iroha {
		system: alphabetic;
		symbols: "\30A4" "\30ED" "\30CF" "\30CB" "\30DB" "\30D8" "\30C8" "\30C1" "\30EA" "\30CC" "\30EB" "\30F2" "\30EF" "\30AB" "\30E8" "\30BF" "\30EC" "\30BD" "\30C4" "\30CD" "\30CA" "\30E9" "\30E0" "\30A6" "\30F0" "\30CE" "\30AA" "\30AF" "\30E4" "\30DE" "\30B1" "\30D5" "\30B3" "\30A8" "\30C6" "\30A2" "\30B5" "\30AD" "\30E6" "\30E1" "\30DF" "\30B7" "\30F1" "\30D2" "\30E2" "\30BB" "\30B9";
		/* イ ロ ハ ニ ホ ヘ ト チ リ ヌ ル ヲ ワ カ ヨ タ レ ソ ツ ネ ナ ラ ム ウ ヰ ノ オ ク ヤ マ ケ フ コ エ テ ア サ キ ユ メ ミ シ ヱ ヒ モ セ ス */
		suffix: "、";
	}
	

Symbolic: ''disc'', ''circle'', ''square'', ''disclosure-open'', ''disclosure-closed''

disc
A filled circle, similar to • U+2022 BULLET.
circle
A hollow circle, similar to ◦ U+25E6 WHITE BULLET.
square
A filled square, similar to ◾ U+25FE BLACK MEDIUM SMALL SQUARE.
disclosure-open
disclosure-closed
Symbols appropriate for indicating an open or closed disclosure widget, such as the HTML <details> element.
The following stylesheet fragment provides the normative definition of these predefined counter styles:
	@counter-style disc {
		system: cyclic;
		symbols: \2022;
		/* • */
		suffix: " ";
	}

	@counter-style circle {
		system: cyclic;
		symbols: \25E6;
		/* ◦ */
		suffix: " ";
	}

	@counter-style square {
		system: cyclic;
		symbols: \25FE;
		/* ◾ */
		suffix: " ";
	}

	@counter-style disclosure-open {
		system: cyclic;
		suffix: " ";
		/* for symbols, see normative text below */
	}

	@counter-style disclosure-closed {
		system: cyclic;
		suffix: " ";
		/* for symbols, see normative text below */
	}
	
Alternately, a browser may render these styles using a browser-generated image instead of the defined character. If so, the image must look similar to the character, and must be sized to attractively fill a 1em by 1em square. For the ''disclosure-open'' and ''disclosure-closed'' counter styles, the marker must be an image or character suitable for indicating the open and closed states of a disclosure widget, such as HTML's <details> element. If the image is directional, it must respond to the writing mode of the element [[!CSS3-WRITING-MODES]], similar to the bidi-sensitive images feature of the Images 4 module. For example, the ''disclosure-closed'' style might use the characters U+25B8 BLACK RIGHT-POINTING SMALL TRIANGLE (▸) and U+25C2 BLACK LEFT-POINTING SMALL TRIANGLE (◂), while the ''disclosure-open'' style might use the character U+25BE BLACK DOWN-POINTING SMALL TRIANGLE (▾).

Complex Predefined Counter Styles

While authors may define their own counter styles using the ''@counter-style'' rule or rely on the set of predefined counter styles, a few counter styles are described by rules that are too complex to be captured by the predefined algorithms. These counter styles are described in this section. Some of the counter styles specified in this section have custom algorithms for generating counter values, but are otherwise identical to a counter style defined via the ''@counter-style'' rule. For example, an author can reference one of these styles in an ''extends'' system, reusing the algorithm but swapping out some of the other descriptors. All of the counter styles defined in this section have a spoken form of ''numbers'', and use a negative sign.

Longhand East Asian Counter Styles

Chinese, Japanese, and Korean have counter styles which have a “longhand” nature, similar to “thirteen thousand one hundred and twenty-three” in English. Each has both formal and informal variants. The formal styles are typically used in financial and legal documents, as their characters are more difficult to alter into each other.
The following table shows examples of these styles, particularly some ways in which they differ.
Counter Style 0 1 2 3 10 11 99 100 101 6001
''japanese-informal'' 十一 九十九 百一 六千一
''japanese-formal'' 壱拾 壱拾壱 九拾九 壱百 壱百壱 六阡壱
''korean-hangul-formal'' 일십 일십일 구십구 일백 일백일 육천일
''korean-hanja-informal'' 十一 九十九 百一 六千一
''korean-hanja-formal'' 壹拾 壹拾壹 九拾九 壹百 壹百壹 六仟壹
''simp-chinese-informal'' 十一 九十九 一百 一百零一 六千零一
''simp-chinese-formal'' 壹拾 壹拾壹 玖拾玖 壹佰 壹佰零壹 陆仟零壹
''trad-chinese-informal'' 十一 九十九 一百 一百零一 六千零一
''trad-chinese-formal'' 壹拾 壹拾壹 玖拾玖 壹佰 壹佰零壹 陸仟零壹
Because opinions differ on how best to represent numbers 10k or greater using the longhand CJK styles, all of the counter styles defined in this section are defined to have a range of -9999 to 9999, but implementations may support a larger range. Outside the implementation-supported range, the fallback is ''cjk-decimal''. Note: Implementations are encouraged to research and implement counter representations beyond 10k and report back to the CSS Working Group with data when a generally-accepted answer is discovered. Some previous research on this topic is contained in an earlier draft.

Japanese: ''japanese-informal'' and ''japanese-formal''

japanese-informal
Informal Japanese Kanji numbering (e.g., 千百十一)
japanese-formal
Formal Japanese Kanji numbering (e.g. 壱阡壱百壱拾壱)
	@counter-style japanese-informal {
		system: additive;
		range: -9999 9999;
		additive-symbols: 9000 \4E5D\5343, 8000 \516B\5343, 7000 \4E03\5343, 6000 \516D\5343, 5000 \4E94\5343, 4000 \56DB\5343, 3000 \4E09\5343, 2000 \4E8C\5343, 1000 \5343, 900 \4E5D\767E, 800 \516B\767E, 700 \4E03\767E, 600 \516D\767E, 500 \4E94\767E, 400 \56DB\767E, 300 \4E09\767E, 200 \4E8C\767E, 100 \767E, 90 \4E5D\5341, 80 \516B\5341, 70 \4E03\5341, 60 \516D\5341, 50 \4E94\5341, 40 \56DB\5341, 30 \4E09\5341, 20 \4E8C\5341, 10 \5341, 9 \4E5D, 8 \516B, 7 \4E03, 6 \516D, 5 \4E94, 4 \56DB, 3 \4E09, 2 \4E8C, 1 \4E00, 0 \3007;
		/* 9000 九千, 8000 八千, 7000 七千, 6000 六千, 5000 五千, 4000 四千, 3000 三千, 2000 二千, 1000 千, 900 九百, 800 八百, 700 七百, 600 六百, 500 五百, 400 四百, 300 三百, 200 二百, 100 百, 90 九十, 80 八十, 70 七十, 60 六十, 50 五十, 40 四十, 30 三十, 20 二十, 10 十, 9 九, 8 八, 7 七, 6 六, 5 五, 4 四, 3 三, 2 二, 1 一, 0 〇 */
		suffix: '\3001';
		/* 、 */
		negative: "\30DE\30A4\30CA\30B9";
		/* マイナス */
		fallback: cjk-decimal;
	}

	@counter-style japanese-formal {
		system: additive;
		range: -9999 9999;
		additive-symbols: 9000 \4E5D\9621, 8000 \516B\9621, 7000 \4E03\9621, 6000 \516D\9621, 5000 \4F0D\9621, 4000 \56DB\9621, 3000 \53C2\9621, 2000 \5F10\9621, 1000 \58F1\9621, 900 \4E5D\767E, 800 \516B\767E, 700 \4E03\767E, 600 \516D\767E, 500 \4F0D\767E, 400 \56DB\767E, 300 \53C2\767E, 200 \5F10\767E, 100 \58F1\767E, 90 \4E5D\62FE, 80 \516B\62FE, 70 \4E03\62FE, 60 \516D\62FE, 50 \4F0D\62FE, 40 \56DB\62FE, 30 \53C2\62FE, 20 \5F10\62FE, 10 \58F1\62FE, 9 \4E5D, 8 \516B, 7 \4E03, 6 \516D, 5 \4F0D, 4 \56DB, 3 \53C2, 2 \5F10, 1 \58F1, 0 \96F6;
		/* 9000 九阡, 8000 八阡, 7000 七阡, 6000 六阡, 5000 伍阡, 4000 四阡, 3000 参阡, 2000 弐阡, 1000 壱阡, 900 九百, 800 八百, 700 七百, 600 六百, 500 伍百, 400 四百, 300 参百, 200 弐百, 100 壱百, 90 九拾, 80 八拾, 70 七拾, 60 六拾, 50 伍拾, 40 四拾, 30 参拾, 20 弐拾, 10 壱拾, 9 九, 8 八, 7 七, 6 六, 5 伍, 4 四, 3 参, 2 弐, 1 壱, 0 零 */
		suffix: '\3001';
		/* 、 */
		negative: "\30DE\30A4\30CA\30B9";
		/* マイナス */
		fallback: cjk-decimal;
	}
	

Korean: ''korean-hangul-formal'', ''korean-hanja-informal'', and ''korean-hanja-formal''

korean-hangul-formal
Korean Hangul numbering (e.g., 일천일백일십일)
korean-hanja-informal
Informal Korean Hanja numbering (e.g., 千百十一)
korean-hanja-formal
Formal Korean Han (Hanja) numbering (e.g., 壹仟壹百壹拾壹)
	@counter-style korean-hangul-formal {
		system: additive;
		range: -9999 9999;
		additive-symbols: 9000 \AD6C\CC9C, 8000 \D314\CC9C, 7000 \CE60\CC9C, 6000 \C721\CC9C, 5000 \C624\CC9C, 4000 \C0AC\CC9C, 3000 \C0BC\CC9C, 2000 \C774\CC9C, 1000 \C77C\CC9C, 900 \AD6C\BC31, 800 \D314\BC31, 700 \CE60\BC31, 600 \C721\BC31, 500 \C624\BC31, 400 \C0AC\BC31, 300 \C0BC\BC31, 200 \C774\BC31, 100 \C77C\BC31, 90 \AD6C\C2ED, 80 \D314\C2ED, 70 \CE60\C2ED, 60 \C721\C2ED, 50 \C624\C2ED, 40 \C0AC\C2ED, 30 \C0BC\C2ED, 20 \C774\C2ED, 10 \C77C\C2ED, 9 \AD6C, 8 \D314, 7 \CE60, 6 \C721, 5 \C624, 4 \C0AC, 3 \C0BC, 2 \C774, 1 \C77C, 0 \C601;
		/* 9000 구천, 8000 팔천, 7000 칠천, 6000 육천, 5000 오천, 4000 사천, 3000 삼천, 2000 이천, 1000 일천, 900 구백, 800 팔백, 700 칠백, 600 육백, 500 오백, 400 사백, 300 삼백, 200 이백, 100 일백, 90 구십, 80 팔십, 70 칠십, 60 육십, 50 오십, 40 사십, 30 삼십, 20 이십, 10 일십, 9 구, 8 팔, 7 칠, 6 육, 5 오, 4 사, 3 삼, 2 이, 1 일, 0 영 */
		suffix: ', ';
		negative: "\B9C8\C774\B108\C2A4  ";
		/* 마이너스 (followed by a space) */
	}

	@counter-style korean-hanja-informal {
		system: additive;
		range: -9999 9999;
		additive-symbols: 9000 \4E5D\5343, 8000 \516B\5343, 7000 \4E03\5343, 6000 \516D\5343, 5000 \4E94\5343, 4000 \56DB\5343, 3000 \4E09\5343, 2000 \4E8C\5343, 1000 \5343, 900 \4E5D\767E, 800 \516B\767E, 700 \4E03\767E, 600 \516D\767E, 500 \4E94\767E, 400 \56DB\767E, 300 \4E09\767E, 200 \4E8C\767E, 100 \767E, 90 \4E5D\5341, 80 \516B\5341, 70 \4E03\5341, 60 \516D\5341, 50 \4E94\5341, 40 \56DB\5341, 30 \4E09\5341, 20 \4E8C\5341, 10 \5341, 9 \4E5D, 8 \516B, 7 \4E03, 6 \516D, 5 \4E94, 4 \56DB, 3 \4E09, 2 \4E8C, 1 \4E00, 0 \96F6;
		/* 9000 九千, 8000 八千, 7000 七千, 6000 六千, 5000 五千, 4000 四千, 3000 三千, 2000 二千, 1000 千, 900 九百, 800 八百, 700 七百, 600 六百, 500 五百, 400 四百, 300 三百, 200 二百, 100 百, 90 九十, 80 八十, 70 七十, 60 六十, 50 五十, 40 四十, 30 三十, 20 二十, 10 十, 9 九, 8 八, 7 七, 6 六, 5 五, 4 四, 3 三, 2 二, 1 一, 0 零 */
		suffix: ', ';
		negative: "\B9C8\C774\B108\C2A4  ";
		/* 마이너스 (followed by a space) */
	}

	@counter-style korean-hanja-formal {
		system: additive;
		range: -9999 9999;
		additive-symbols: 9000 \4E5D\4EDF, 8000 \516B\4EDF, 7000 \4E03\4EDF, 6000 \516D\4EDF, 5000 \4E94\4EDF, 4000 \56DB\4EDF, 3000 \53C3\4EDF, 2000 \8CB3\4EDF, 1000 \58F9\4EDF, 900 \4E5D\767E, 800 \516B\767E, 700 \4E03\767E, 600 \516D\767E, 500 \4E94\767E, 400 \56DB\767E, 300 \53C3\767E, 200 \8CB3\767E, 100 \58F9\767E, 90 \4E5D\62FE, 80 \516B\62FE, 70 \4E03\62FE, 60 \516D\62FE, 50 \4E94\62FE, 40 \56DB\62FE, 30 \53C3\62FE, 20 \8CB3\62FE, 10 \58F9\62FE, 9 \4E5D, 8 \516B, 7 \4E03, 6 \516D, 5 \4E94, 4 \56DB, 3 \53C3, 2 \8CB3, 1 \58F9, 0 \96F6;
		/* 9000 九仟, 8000 八仟, 7000 七仟, 6000 六仟, 5000 五仟, 4000 四仟, 3000 參仟, 2000 貳仟, 1000 壹仟, 900 九百, 800 八百, 700 七百, 600 六百, 500 五百, 400 四百, 300 參百, 200 貳百, 100 壹百, 90 九拾, 80 八拾, 70 七拾, 60 六拾, 50 五拾, 40 四拾, 30 參拾, 20 貳拾, 10 壹拾, 9 九, 8 八, 7 七, 6 六, 5 五, 4 四, 3 參, 2 貳, 1 壹, 0 零 */
		suffix: ', ';
		negative: "\B9C8\C774\B108\C2A4  ";
		/* 마이너스 (followed by a space) */
	}
	

Chinese: ''simp-chinese-informal'', ''simp-chinese-formal'', ''trad-chinese-informal'', and ''trad-chinese-formal''

simp-chinese-informal
Simplified Chinese informal numbering (e.g., 一千一百一十一)
simp-chinese-formal
Simplified Chinese formal numbering (e.g. 壹仟壹佰壹拾壹)
trad-chinese-informal
Traditional Chinese informal numbering (e.g., 一千一百一十一)
trad-chinese-formal
Traditional Chinese informal numbering (e.g., 壹仟壹佰壹拾壹)
cjk-ideographic
This counter style is identical to ''trad-chinese-informal''. (It exists for legacy reasons.)
The Chinese longhand styles are defined by almost identical algorithms (specified as a single algorithm here, with the differences called out when relevant), but use different sets of characters, as specified by the table following the algorithm.
  1. If the counter value is 0, the representation is the character for 0 specified for the given counter style. Skip the rest of this algorithm.
  2. Initially represent the counter value as a decimal number. For each digit that is not 0, append the appropriate digit marker to the digit. The ones digit has no marker.
  3. For the informal styles, if the counter value is between ten and nineteen, remove the tens digit (leave the digit marker).
  4. Drop any trailing zeros and collapse any remaining zeros into a single zero digit.
  5. Replace the digits 0-9 with the appropriate character for the given counter style. Return the resultant string as the representation of the counter value.
For all of these counter styles, the 'suffix' is "、" U+3001, the 'fallback' is ''cjk-decimal'', the 'range' is ''-9999 9999'', and the 'negative' value is given in the table of symbols for each style. The following tables define the characters used in these styles:
Values Codepoints
simp-chinese-informal simp-chinese-formal trad-chinese-informal trad-chinese-formal
Digit 0 零 U+96F6 零 U+96F6 零 U+96F6 零 U+96F6
Digit 1 一 U+4E00 壹 U+58F9 一 U+4E00 壹 U+58F9
Digit 2 二 U+4E8C 贰 U+8D30 二 U+4E8C 貳 U+8CB3
Digit 3 三 U+4E09 叁 U+53C1 三 U+4E09 參 U+53C3
Digit 4 四 U+56DB 肆 U+8086 四 U+56DB 肆 U+8086
Digit 5 五 U+4E94 伍 U+4F0D 五 U+4E94 伍 U+4F0D
Digit 6 六 U+516D 陆 U+9646 六 U+516D 陸 U+9678
Digit 7 七 U+4E03 柒 U+67D2 七 U+4E03 柒 U+67D2
Digit 8 八 U+516B 捌 U+634C 八 U+516B 捌 U+634C
Digit 9 九 U+4E5D 玖 U+7396 九 U+4E5D 玖 U+7396
Tens Digit Marker 十 U+5341 拾 U+62FE 十 U+5341 拾 U+62FE
Hundreds Digit Marker 百 U+767E 佰 U+4F70 百 U+767E 佰 U+4F70
Thousands Digit Marker 千 U+5343 仟 U+4EDF 千 U+5343 仟 U+4EDF
Negative Sign 负 U+8D1F 负 U+8D1F 負 U+8CA0 負 U+8CA0
For reference, here are the first 120 values for the ''simp-chinese-informal'' style:
  1     一    41   四十一    81   八十一
  2     二    42   四十二    82   八十二
  3     三    43   四十三    83   八十三
  4     四    44   四十四    84   八十四
  5     五    45   四十五    85   八十五
  6     六    46   四十六    86   八十六
  7     七    47   四十七    87   八十七
  8     八    48   四十八    88   八十八
  9     九    49   四十九    89   八十九
 10     十    50    五十    90    九十
 11    十一    51   五十一    91   九十一
 12    十二    52   五十二    92   九十二
 13    十三    53   五十三    93   九十三
 14    十四    54   五十四    94   九十四
 15    十五    55   五十五    95   九十五
 16    十六    56   五十六    96   九十六
 17    十七    57   五十七    97   九十七
 18    十八    58   五十八    98   九十八
 19    十九    59   五十九    99   九十九
 20    二十    60    六十   100    一百
 21   二十一    61   六十一   101  一百零一
 22   二十二    62   六十二   102  一百零二
 23   二十三    63   六十三   103  一百零三
 24   二十四    64   六十四   104  一百零四
 25   二十五    65   六十五   105  一百零五
 26   二十六    66   六十六   106  一百零六
 27   二十七    67   六十七   107  一百零七
 28   二十八    68   六十八   108  一百零八
 29   二十九    69   六十九   109  一百零九
 30    三十    70    七十   110  一百一十
 31   三十一    71   七十一   111 一百一十一
 32   三十二    72   七十二   112 一百一十二
 33   三十三    73   七十三   113 一百一十三
 34   三十四    74   七十四   114 一百一十四
 35   三十五    75   七十五   115 一百一十五
 36   三十六    76   七十六   116 一百一十六
 37   三十七    77   七十七   117 一百一十七
 38   三十八    78   七十八   118 一百一十八
 39   三十九    79   七十九   119 一百一十九
 40    四十    80    八十   120  一百二十

Ethiopic Numeric Counter Style: ''ethiopic-numeric''

The ethiopic-numeric counter style is defined for all positive non-zero numbers. The following algorithm converts decimal digits to ethiopic numbers:
  1. If the number is 1, return "፩" (U+1369).
  2. Split the number into groups of two digits, starting with the least significant decimal digit.
  3. Index each group sequentially, starting from the least significant as group number zero.
  4. If the group has the value zero, or if the group is the most significant one and has the value 1, or if the group has an odd index (as given in the previous step) and has the value 1, then remove the digits (but leave the group, so it still has a separator appended below).
  5. For each remaining digit, substitute the relevant ethiopic character from the list below.
    Tens Units
    Values Codepoints Values Codepoints
    10 U+1372 1 U+1369
    20 U+1373 2 U+136A
    30 U+1374 3 U+136B
    40 U+1375 4 U+136C
    50 U+1376 5 U+136D
    60 U+1377 6 U+136E
    70 U+1378 7 U+136F
    80 U+1379 8 U+1370
    90 U+137A 9 U+1371
  6. For each group with an odd index (as given in the second step), except groups which originally had a value of zero, append ፻ U+137B.
  7. For each group with an even index (as given in the second step), except the group with index 0, append ፼ U+137C.
  8. Concatenate the groups into one string, and return it.
For this system, the name is "ethiopic-numeric", the 'range' is ''1 infinite'', the 'suffix' is "/ " (U+002F SOLIDUS followed by a U+0020 SPACE), and the rest of the descriptors have their initial value.
The decimal number 100, in ethiopic, is ፻ U+137B The decimal number 78010092, in ethiopic, is ፸፰፻፩፼፺፪ U+1378 U+1370 U+137B U+1369 U+137C U+137A U+136A. The decimal number 780100000092, in ethiopic, is ፸፰፻፩፼፼፺፪ U+1378 U+1370 U+137B U+1369 U+137C U+137C U+137A U+136A.

Additional Predefined Counter Styles

The Internationalization Working Group maintains a large list of predefined ''@counter-style'' rules for various world languages in their Predefined Counter Styles document. [[predefined-counter-styles]] These additional counter styles are not intended to be supported by user-agents by default, but can be used by users or authors copying them directly into style sheets.

APIs

Extensions to the CSSRule interface

The CSSRule interface is extended as follows:
	partial interface CSSRule {
	    const unsigned short COUNTER_STYLE_RULE = 11;
	};
	

The CSSCounterStyleRule interface

The CSSCounterStyleRule interface represents a ''@counter-style'' rule.
	interface CSSCounterStyleRule : CSSRule {
	  attribute DOMString name;
	  attribute DOMString system;
	  attribute DOMString symbols;
	  attribute DOMString additiveSymbols;
	  attribute DOMString negative;
	  attribute DOMString prefix;
	  attribute DOMString suffix;
	  attribute DOMString range;
	  attribute DOMString pad;
	  attribute DOMString speakAs;
	  attribute DOMString fallback;
	};
	
name of type DOMString
The name attribute on getting must return a DOMString object that contains the serialization of the <> defined for the associated rule. On setting the name attribute, run the following steps:
  1. Parse a component value from the value.
  2. If the returned value is an <>, and the <>’s representation is not an ASCII case-insensitive match for "decimal" or "none", replace the associated rule's name with the <>'s representation. If the <>’s respresentation is an ASCII case-insensitive match for any of the other predefined counter styles, lowercase the representation before replacing the associated rule's name with it.
  3. Otherwise, do nothing.
system of type DOMString
symbols of type DOMString
additiveSymbols of type DOMString
negative of type DOMString
prefix of type DOMString
suffix of type DOMString
range of type DOMString
pad of type DOMString
speakAs of type DOMString
fallback of type DOMString
The remaining attributes on getting must return a DOMString object that contains the serialization of the associated descriptor defined for the associated rule. If the descriptor was not specified in the associated rule, the attribute must return an empty string. On setting, run the following steps:
  1. Parse a list of component values from the value.
  2. If the returned value is invalid according to the given descriptor's grammar, or would cause the ''@counter-style'' rule to become invalid, do nothing and abort these steps. (For example, some systems require the 'symbols' descriptor to contain two values.)
  3. If the attribute being set is system, and the new value would change the algorithm used, do nothing and abort these steps. It's okay to change an aspect of the algorithm, like the first symbol value of a ''fixed'' system.
  4. Set the descriptor to the value.

Sample style sheet for HTML

This section is informative, not normative. HTML itself defines the styles that apply to its elements, and in some cases defers to the user agent's discretion.
	details > summary {
		display: list-item;
		list-style: disclosure-closed inside;
	}

	details[open] > summary {
		list-style: disclosure-open inside;
	}
	

Changes since the Feb 2015 Candidate Recommendation

* Allowed UAs to extend the ''hebrew'' style past the spec-defined limits (since the current limits are mostly just an artifact of how annoying it is to go higher with the ''@counter-style''-based definition).

Acknowledgments

The following people and documentation they wrote were very useful for defining the numbering systems: Alexander Savenkov, Arron Eicholz, Aryeh Gregor, Christopher Hoess, Daniel Yacob, Frank Tang, Jonathan Rosenne, Karl Ove Hufthammer, Musheg Arakelyan, Nariné Renard Karapetyan, Randall Bart, Richard Ishida, Simon Montagu (Mozilla, smontagu@smontagu.org) Special thanks to Xidorn Quan for extensive reviews of all aspects of the spec.