[css-content-3] Animation of 'content' #8623
Description
Currently the Animation Type of the content property is “discrete”. However, because the none value can cause the box to disappear when applied to a pseudo-element, this has similar problems to display: none in keyframes, see discussion in #6429
The solution we chose for display: none was to replace it with display: revert-layer in keyframes. But that doesn't quite work for content for two reasons:
content: noneon regular elements does not delete the box, only its contents, so it's not necessary to limit itcontent: normalon certain pseudo-elements computes tonone, so it needs to be limited also.
Possible options I can think of, none of which seem amazing...
- Both
noneandnormalare excluded from keyframes, and are converted torevert-layer. - A computed value of
nonein an animation or transition frame (i.e. that originated in either the Animations or Transitions cascade origins) is converted to"". - A computed value of
nonein a keyframe is converted to""only on the::before/::afterpseudo-elements. - We make
contentNot Animatable. - Something else?