I was just thinking that. I don't do much with CSS directly (I know enough to be dangerous) but I kept thinking "Ok, now it will start beating" and then 2-3 more lines of practically gibberish and rinse and repeat until the end when it started beating.

WAY too much CSS to do something like that. I'm not sure what the fix is though? A JS library to generate the CSS animation with a saner syntax (I realise CSS probably needs all of that stuff to be extendable but it's a massive amount of code for something that should be easier to accomplish IMHO).