Check out this link! It's not like it'll crash your iPhone or anything (Hint: Of course it will)
https://www.theregister.co.uk/2018/09/17/safari_reaper/Apple iPhones, iPads, and Mac computers that stray onto websites with malicious CSS code, while using Safari, can crash or fall over – due to a flaw in the web browser.
The WebKit rendering engine vulnerability can be triggered by just a few lines of code in a cascading style sheet (CSS). On iOS devices, at least, it all starts to go wrong when the browser tries to parse a processor-intensive CSS feature called backdrop-filter on nested page elements.
to actually run the code go here, it has chrome and firefox as well;
https://www.reaperbugs.com/index --- see if you can pull your system from oblivion or if it nosedives... but dont have anything important open when you try it...