Animations.css

.animation-area {
    background: black;
    width: 100%;
    height: 100vh;
}

.box-area {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
}

.box-area li {
    position: absolute;
    display: block;
    list-style: none;
    width: 25px;
    height: 25px;
    background: rgba(255, 255, 255, 0.2);
    animation: animate 20s linear infinite;
    bottom: -150px;
}

.box-area li:nth-child(1) {
    left: 86%;
    width: 80px;
    height: 80px;
    animation-delay: 0s;
}

.box-area li:nth-child(2) {
    left: 12%;
    width: 30px;
    height: 30px;
    animation-delay: 1.5s;
    animation-duration: 10s;
}

.box-area li:nth-child(3) {
    left: 70%;
    width: 100px;
    height: 100px;
    animation-delay: 5.5s;
}

.box-area li:nth-child(4) {
    left: 42%;
    width: 150px;
    height: 150px;
    animation-delay: 0s;
    animation-duration: 15s;
}

.box-area li:nth-child(5) {
    left: 65%;
    width: 40px;
    height: 40px;
    animation-delay: 0s;
}

.box-area li:nth-child(6) {
    left: 15%;
    width: 110px;
    height: 110px;
    animation-delay: 3.5s;
}

@keyframes animate {
0% {
    transform: translateY(0) rotate(0deg);
    opacity: 1;
}

100% {
    transform: translateY(-800px) rotate(360deg);
    opacity: 0;
}
}