Transition vs Animated https://developer.mozilla.org/en-US/docs/Web/Apps/Fundamentals/Performance/CSS_JavaScript_animation_performance > Even given the test results above, we'd argue that CSS animations are the better choice. But how? The key is that as long as the properties we want to animate do not trigger reflow/repaint (read CSS triggers for more information), we can move those sampling operations out of the main thread.