Amphtml: AMP Stories: Publisher Served Ad CTA button hidden in Firefox

[AutadeJS]

What's the issue?

In AMP stories, the CTA button in Publisher Served Ad doesn't display in Firefox.

How do we reproduce the issue?

Check this in latest version of Firefox:
https://ampbyexample.com/stories/monetization/publisher_served/preview/embed/
In this AMP story example, look for ad. You won't see CTA button in the ad, while you'll see one when you check on Chrome and Edge.

[newmuis]

Thanks for the report @AutadeJS! I'll take a look.

/cc @calebcordry

[newmuis]

Looks like somehow the transition isn't happening in Firefox.

[calebcordry]

Did some digging, this has to do with differences in how browsers handle animations on styles set with !important. Apparently, in Chrome styles defined in @keyframes will take precedence over !important but in Firefox they will not. I am working on a solution.

[calebcordry]

closed by #16103. Let me know if you are still seeing this issue once this fix hits production. Thanks!