@keyframes fall{0%{transform:translateY(-100vh);opacity:1}to{transform:translateY(100vh);opacity:0}}.balloon-container{position:fixed;top:0;left:0;width:100%;height:100%;pointer-events:none;overflow:hidden;z-index:999}.balloon{position:absolute;width:50px;height:60px;background-color:red;border-radius:50%;animation:fall 5s linear infinite}.balloon:nth-child(1){left:10%;background-color:#00f;animation-duration:4s}.balloon:nth-child(2){left:30%;background-color:#ff0;animation-duration:5s}.balloon:nth-child(3){left:50%;background-color:green;animation-duration:6s}.balloon:nth-child(4){left:70%;background-color:orange;animation-duration:4.5s}.balloon:nth-child(5){left:90%;background-color:pink;animation-duration:5.5s}