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Last active Feb 27, 2019

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Day 2: Specs Reading: CSS Snapshot 2018 (Overview)


What is CSS?

Cascading Style Sheet!

CSS is a language for describing the rendering of structured documents (such as HTML and XML) on screen, on paper, etc.

What is CSS Snapshot?

The document that represents the state of CSS as of each year.

What are the three levels of stability a CSS document has to pass through? What happens during each of those phases?

  1. Working Draft (WD) - design phase
  • FPWD -> LCWD
    • First Public Working Draft(FPWD) is the draft published since whole WG has agreed to work on the module.
    • Last Call Working Draft(LCWD) is the draft published since we have resolved all known issues with feedback.
  1. Candidate Recommendation (CR) - testing phase
  • testing -> PR
    • In testing phase, it reveal hiddlen problems with the spec. and it's morphed in response to feedback through testing and implementation of specification for test.
    • Proposed Recommendation(PR) is the stage to exit CR, so WG builds a test suite and generates implementation reports. In order to transfer to REC, W3C Advisory Commitee must approve the transition.
  1. Recommendation (REC) - completed, remain maintenance phase
  • the point of REC is that WG only maintains errata document and occationly publishes an updated edition that incorporates the errata back into the spec.

What are CSS Levels?

It's simillar with the concept called 'version'. but CSS has levels, not version.

because each level of CSS builds on the previous, refining definitions and adding features. (it seems CSS also use cascading for its scalability. that's awesome)

What is CSS Level 3?

WG considers the CSS1 specification to be obsolete. CSS2.1 specification to be W3C recommendation.

CSS Level 3 builds on CSS Level 2 module by module. It is developed not to contradict the CSS2.1, So WG only add functionality and refine definitions. (it will be plugged in to the CSS2.1 system plus previously-completed modules)

Starts from CSS Level 3, all modules are levelled independently.

those independent modules can reach level 4 or beyond, but CSS language no longer has levels. So, CSS Level 3 as a term is used only to differenitate it from previous versions.

Where do Vendor-prefixing Unstable Features come from?

It's from UA(User Agent). According to De Facto Standards..

If feature is unstable, at least three UAs implement the feature. When exposing unstable feature to the Web in a production release, implementations should support both "vendor-prefixed" and "unprefixed syntaxes" for the feature.

it's hard to read specification in English to non-native me.. but it's very interesting and helpful. I didn't know that to specify CSS takes long time with many resources before. that process definitely remarkable. and re-realize that CSS is most powerful and attractive language. I'm into it more with this reading.

comment or ask something or correct some missing... whatever reply on this markdown. thanks for reading! let's study together, happily. 😃

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