.stairs{.transition-container{position:fixed;width:100vw;height:100vh;display:flex;left:0;top:0;pointer-events:none;z-index:100;div{position:relative;height:100%;width:100%;background-color:white}}.transition-background{position:fixed;width:100%;height:100vh;background-color:black;z-index:100;pointer-events:none;top:0;left:0}}@keyframes spread{0%{transform:translate(var(--sx),var(--sy)) scale(1.5);opacity:1}to{transform:translate(var(--dx),var(--dy)) scale(1);opacity:0}}.particle{position:absolute;border-radius:50%;animation:spread 1.5s ease-out forwards;will-change:transform,opacity;pointer-events:none}