CSS

This is the Mozilla wiki home page for Cascading Style Sheets (CSS).

• CSS/
• CSS/:autofill
• CSS/Houdini
• CSS/text-overflow
• CSS/text-size-adjust

CSS

Platform priorities

The following CSS specs/proposal are a priority for the Platform.

Actively Implementing

Flexbox

Mozilla has a pretty solid complete Flexbox (W3C CR) implementation. We are working on some fixes to make it even better, e.g.

• 812687

Grid

• CSS Grid (CR) including subgrid value
  • lots of work (including for subgrid)

Shapes

• CSS Shapes (CR) metabug, shape-outside

Houdini

• CSS Houdini - see inside for Houdini implementation thoughts/plan

Box Alignment

• CSS Alignment (WD), https://bugzilla.mozilla.org/show_bug.cgi?id=1105570
  • all properties for blocks (1040695, 1105571)
  • and some details for flexbox (see 1105570 Depends on)

Multicolumn

• CSS multicol unprefixing, column-span, a11y bug hack removal, , column-break

3D Transforms

• 3D Transform interop / spec changes

Inline Layout

• CSS Inline Layout Module Level 3 (TR WD) - specifically just CSS Initial-letter related features

Masking

• CSS clip-path (W3C WD)

Under the hood and related

• Stylo
• Web Animations API
• PDF support
• Intersection observer
• Resize observer

Evaluating

• Colors 4 syntax
• Color improvements (wide gamut, color correction, note CSS color correction preffed off)
• CSS Media Queries 4 work (interaction, negation, etc) - https://bugzilla.mozilla.org/show_bug.cgi?id=1035774
• Selectors4
  • CSS :placeholder-shown
  • CSS :focus-within
  • CSS ::selection fixes + unprefixes
• SVG related
  • [] attr function
  • [] xywh fragment syntax
  • [] SVG image sizing

• CSS Containment size/layout, style, paint

• CSS Font Loading Improvements, Multiple bugs e.g., https://bugzilla.mozilla.org/show_bug.cgi?id=1157064
• font inflation removed
• style sheet APIs in add-ons SDK / loading async APIs (to be handled by stylo)
• Filter Effects Module Level 2 - backdrop-filter
• CSS Transform properties (shorthands)

Upcoming CRs

At the TPAC 2016 CSS WG f2f, the WG resolved to work on taking the following WDs to CR by end of 2016.

• Box Alignment (see above)
• Cascade
  • New features since CSS2.x:
    • 'all' property
    • 'unset' keyword
    • scoped styles, animations, and transitions in the cascade.
• Grid (see above)
• Media Queries 4 (note: new features in 4)
• Scroll Snap (CR)
• Selectors 4 (need list of changes since 3)
• Text (progress, need list of changes since CSS 2.1)

For all potential CRs:

• Which browsers have openly announced implementations or intent to implement? (links?)

Related HTML5

HTML5 layout and presentation related work:

• srcset intrinsic size
• dialog element (fullscreen interactions, and since showModalDialog being deprecated/removed) #840640
• ...

Shipping Soon

As the above priorities get implemented, moving down here to note we're waiting for them to ship.

49:

• CSS Masking (2014 CR), https://bugzilla.mozilla.org/show_bug.cgi?id=686281
• CSS handling of HTML5 <details> <summary> - https://bugzilla.mozilla.org/show_bug.cgi?id=591737
• Background-position x/y

48:

• calc() for numbers / unit algebra (CR/WD), https://bugzilla.mozilla.org/show_bug.cgi?id=594933

properties

Please add subpages for each (unprefixed) CSS property in alphabetical order.

• ...
• overflow
• ...
• text-overflow
• ...

in development

CSS properties which have not yet made it to a Candidate Recommendation (or later), or are only implemented in the wild in prefixed form.

new pseudo-classes

• ...
• :autofill
• ...

new properties

• ...
• text-size-adjust (-moz-, -ms-, -webkit-)
• ...

see also

• https://developer.mozilla.org/en/CSS
• CSS3
• HTML5
• Standards