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The additive-symbols descriptor is similar to the symbols descriptor and allows the user to specify symbols to be used for counter representations when the value of the system descriptor is additive. The additive-symbols descriptor defines what are known as additive tuples, each of which is a pair containing a symbol and a non-negative integer weight. The additive system is used to construct sign-value numbering systems such as the Roman numerals.

When the value of the system descriptor is cyclic, numeric, alphabetic, symbolic, or fixed, the symbols descriptor is used instead of additive-symbols to specify counter symbols.

Related at-rule@counter-style
Initial valueN/A
Computed valueas specified
Canonical orderorder of appearance in the formal grammar of the values


additive-symbols: 3 "0";
additive-symbols: 3 "0", 2 "\2E\20";
additive-symbols: 3 "0", 2 url(symbol.png);

Formal syntax

[ <integer> && <symbol> ]#

<symbol> = <string> | <image> | <ident>


HTML Content

<ul class="list">

CSS Content

@counter-style additive-symbols-example {
  system: additive;
  additive-symbols: I 1;
.list {
  list-style: additive-symbols-example;



Specification Status Comment
CSS Counter Styles Level 3
The definition of 'additive-symbols' in that specification.
Candidate Recommendation Initial definition

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support No support 33 (33) No support No support No support
Feature Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support No support 33 (33) No support No support No support

See also

Document Tags and Contributors

 Contributors to this page: duncanmcdonald, Sebastianz, kscarfone, jsx
 Last updated by: duncanmcdonald,