Math function easeInSine(x) { return 1 - Math.cos((x * Math.PI) / 2); } CSS transition: transform 0.5s cubic-bezier(0.12, 0, 0.39, 0) Math function easeOutSine(x) { return Math.sin((x * Math.PI) / 2); } CSS transition: transform 0.5s cubic-bezier(0.61, 1, 0.88, 1)