The former engineer seems to be missing the point.
All this site does is present existing CSS animation methods in a convenient, curated fashion with nice variations such as "wobble left". We know it works on mobile because the code is written according to the CSS spec.
If you have doubts about whether the CSS animation works on mobile, then you have doubts about whether the CSS animation spec in general works on mobile.
Developers don't copy and paste and write code on their mobile phones. Therefore the target audience is not your "50% of web users" club, which is a consumption stat, not coding or technical productivity/creating.
The code that you take from this site goes to your own project, and that's when you test on mobile - with your own HTML elements and other code.
Finally, "mobile first" is not right. Nothing should be "first" because by definition everything else is given less priority which is flawed logic depending on the application. "Mobile-friendly" is the more sensible idea.
You are not entitled to "Mobile First" just because a conga line of over-memed industry bloggers repeatedly insist we are entitled to all the content on the internet through our mobile browsers.
You're waving your phone around like it's attached permanently to your hand, and the only way you can get online!
The site responds and tells you what's going on. There is no fault. Be patient, be cool, save the bookmark and check it our later.
Don't be the kid throwing a tantrum because the hand-me-down phone you got for Christmas doesn't run Pokemon Go.
Screen size is an inherent limitation of mobile, always will be. Video editing, photo-editing, anything requiring a complex interface on a single page, or anything the developer hasn't released yet for reasons which are their business.
Giving release priority to desktop (including laptop) for a technical development app is OKAY in 2017. Just breath, everything is okay. The site is trustworthy, the code is trustworthy.
All this site does is present existing CSS animation methods in a convenient, curated fashion with nice variations such as "wobble left". We know it works on mobile because the code is written according to the CSS spec.
If you have doubts about whether the CSS animation works on mobile, then you have doubts about whether the CSS animation spec in general works on mobile.
Developers don't copy and paste and write code on their mobile phones. Therefore the target audience is not your "50% of web users" club, which is a consumption stat, not coding or technical productivity/creating.
The code that you take from this site goes to your own project, and that's when you test on mobile - with your own HTML elements and other code.
Finally, "mobile first" is not right. Nothing should be "first" because by definition everything else is given less priority which is flawed logic depending on the application. "Mobile-friendly" is the more sensible idea.