technology for custom downloadable fonts and typography for web and TV devices. Specification maturation Sometimes, when a specification becomes too large, it is split into independent modules that can mature at their own pace. Subsequent editions of a module or specification are known as levels and are denoted by the first integer in the title (e.g. CSS3 = Level 3). Subsequent revisions on each level are denoted by an integer following a decimal point (for example, CSS2.1 = Revision 1). The W3C standard formation process is defined within the W3C process document, outlining four maturity levels through which each new standard or recommendation must progress. Working draft (WD) After enough content has been gathered from 'editor drafts' and discussion, it may be published as a working draft (WD) for review by the community. A WD document is the first form of a standard that is publicly available. Commentary by virtually anyone is accepted, though no promises are made with regard to action on any particular element commented upon. At this stage, the standard document may have significant differences from its final form. As such, anyone who implements WD standards should be ready to significantly modify their implementations as the standard matures. Candidate recommendation (CR) A candidate recommendation is a version of a standard that is more mature than the WD. At this point, the group responsible for the standard is satisfied that the standard meets its goal. The purpose of the CR is to elicit aid from the development community as to how implementable the standard is. The standard document may change further, but at this point, significant features are mostly decided. The design of those features can still change due to feedback from implementors. Proposed recommendation (PR) A proposed recommendation is the version of a standard that has passed the prior two levels. The users of the standard provide input. At this stage, the document is submitted to the W3C Advisory Council for final approval. While this step is important, it rarely causes any significant changes to a standard as it passes to the next phase. W3C recommendation (REC) This is the most mature stage of development. At this point, the standard has undergone extensive review and testing, under both theoretical and practical conditions. The standard is now endorsed by the W3C, indicating its readiness for deployment to the public, and encouraging more widespread support among implementors and authors.