@davatron5000 something I learned recently is that `linear()` is not fully optimized in Safari, so it doesn’t run at the highest frame rates on their ProMotion screens, instead seemingly capped at 60fps. If that’s important, the alternative that worked for me was compiling the spring to WAAPI KeyframeEffect and using that. I assume outputting @keyframes would have worked too. The upside of WAAPI is that you can redefine the spring without additional big CSS output, the downside is it’s not declarative.