What Is CSS3? Cascading Style Sheets Level 3

An Introduction to the Modularization of Cascading Style Sheets (level 3)

CSS3
Wikimedia Commons
by Jennifer Kyrnin
Updated July 15, 2018

The biggest change that is currently planned for CSS level 3 is the introduction of modules. The advantage of modules is that it (supposedly) allows the specification to be completed and approved more quickly because segments are completed and approved in chunks. This also allows browser and user-agent manufacturers to support sections of the specification but keep their code bloat to a minimum by only supporting those modules that make sense. For example, a text reader wouldn't need to include modules that only define how an element is going to display visually. But even if it only included the aural modules, it would still be a standards-compliant CSS 3 tool.

Some New Features of CSS 3

  • Selectors
    • Selectors in CSS 3 are going to be very interesting. They will allow the designer/developer to select on much more specific levels of the document. One of the nice things about this module is that many browsers are already starting to support the advanced CSS 3 selectors, so you can start trying them out now. For example, some new selectors are:
      • matching on attributes and attribute values, including partial matches
    • structural pseudo-classes, such as the nth-child
    • a target pseudo-class to style only elements that are targetted in the URL
    • a checked pseudo-class to style any element that is checked such as radio or checkbox elements
  • Text Effects and Layout
    • Making changes to the hyphenation, whitespace, and justification of text in documents.
  • First-Letter and First-Line Pseudo-Classes
    • CSS 3 should allow properties to affect kerning and alignment of drop-caps.
  • Paged Media and Generated Content
    • CSS 3 will now support more options in paged media, such as running headers and footers and page numbers. Plus there will be advanced properties for printing generated content including properties for footnotes and cross-references.
  • Multi-Column Layout
    • Right now, the multi-column layout working draft provides properties to allow designers to display their content in multiple columns with definitions like the column-gap, column-count, and column-width.
  • Ruby
    • CSS will now support the ability to add small annotations on top or next to words, most often used in Chinese and Japanese. They are generally used to give the pronunciation or meaning of difficult ideograms.

CSS 3 Will Be Fun

Once it's fully adopted as a standard and Web browsers and user-agents begin using it, CSS 3 will be a powerful tool for Web designers. The new features listed above are only a small subset of all the additions and changes to the specification.