Falling Leaves Animation/fallingleaves.css
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Poppins', sans-serif;
}

section{
    position: relative;
    width: 100%;
    height: 100vh;
    background: radial-gradient(#333, #000);
    overflow: hidden;
    display: flex;
    justify-content: center;
    align-items: center;
}

section h3{
    color: #fff;
    font-size: 4em;
    text-transform: uppercase;
}

section .set{
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    pointer-events : none;   
}

.set2{
    transform: scale(2) rotateY(180deg);
    filter: blur(2px);
}
.set3{
    transform: scale(0.8) rotateX(180deg);
    filter: blur(4px);
}

section .set div{
    position: absolute;
    display: block;
}

section .set div:nth-child(1){
    left: 20%;
    animation: animate 15s linear infinite;
    animation-delay: -7s;
}
section .set div:nth-child(2){
    left: 50%;
    animation: animate 20s linear infinite;
    animation-delay: -5s;
}
section .set div:nth-child(3){
    left: 70%;
    animation: animate 20s linear infinite;
    animation-delay: 0s;
}
section .set div:nth-child(4){
    left: 0%;
    animation: animate 15s linear infinite;
    animation-delay: -5s;
}
section .set div:nth-child(5){
    left: 85%;
    animation: animate 18s linear infinite;
    animation-delay: -10s;
}
section .set div:nth-child(6){
    left: 0%;
    animation: animate 12s linear infinite;
    animation-delay: 0s;
}
section .set div:nth-child(7){
    left: 15%;
    animation: animate 14s linear infinite;
    animation-delay: 0s;
}
section .set div:nth-child(8){
    left: 90%;
    animation: animate 18s linear infinite;
    animation-delay: -1s;
}

@keyframes animate {
    0%{
        opacity: 0;
        top: -10%;
        transform: translateX(20px) rotate(0deg);
    }
    10%{
        opacity: 1;
    }
    20%{
        transform: translateX(-20px) rotate(45deg);
    }
    40%{
        transform: translateX(-20px) rotate(90deg);
    }
    60%{
        transform: translateX(20px) rotate(180deg);
    }
    80%{
        transform: translateX(-20px) rotate(180deg);
    }
    100%{
        top: 110%;;
        transform: translateX(-20px) rotate(225deg);
    }
}