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Time-based CSS animations

This post by Chuan about time-based CSS animations has a ton of bonkers CSS tricks that are worth checking out:

After years of wait, CSS now has enough Math functions supported, particularly mod(), round(), and trigonometric functions. It's time to revisit the time-based way of animation, hope it'll be more useful this time.

Chuan uses these functions to set up a custom variable via the CSS Houdini API and then track the time in milliseconds. So beware, this is pretty wild stuff:

@property --t {
	syntax: "<integer>";
	initial-value: 0;
	inherits: true;

@keyframes tick {
	from {
		--t: 0;
	to {
		--t: 86400000;

:root {
	animation: tick 86400000ms linear infinite;

Chaun also works on css-doodle which is a web component for drawing cool and elaborate patterns. All of this stuff is very much worth checking out!