style.css

*{
    padding: 0;
    margin: 0;
}

body{
    background: linear-gradient(to right , skyblue , lightgreen);
}

.navbar ul{
 display: flex;
 justify-content: flex-end;
 list-style: none;

}

.navbar ul li{
    padding: 10px 15px;
}

h2{
    text-align: center;
    justify-content: center;
    padding-top: 270px;
    z-index: 1;
}

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

.boxarea li{
    position: absolute;
    display: block;
    height: 25px;
    width: 25px;
    background: rgba(255,255,28,0.5);
    animation: animate 30s linear infinite;
    bottom: -100px;
    z-index: -1;
}

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

.boxarea li:nth-child(2)
{
    left: 12%;
    width: 30px;
    height: 30px;
    animation-delay: 1.5s;
    animation-duration: 5s;
}
.boxarea li:nth-child(3)
{
    left: 22%;
    width: 80px;
    height: 80px;
    animation-delay: 3.5s;
    animation-duration: 5s;
    color: skyblue;
}

.boxarea li:nth-child(4)
{
    left: 1%;
    width: 100px;
    height: 100px;
    animation-delay: 0s;
    animation-duration: 15s;
   
}   

.boxarea li:nth-child(5)
{
    left: 65%;
    width: 150px;
    height: 150px;
    animation-delay: 0s;
    animation-duration: 5.5s;
} 

.boxarea li:nth-child(6)
{
    left: 15%;
    width: 10px;
    height: 10px;
    animation-delay: 3.5s;
} 

.boxarea li:nth-child(7)
{
    left: 75%;
    width: 110px;
    height: 110px;
    animation-delay: 3.5s;
} 
.boxarea li:nth-child(8)
{
    left: 25%;
    width: 50px;
    height: 50px;
    animation-delay: 8.5s;
} 
.boxarea li:nth-child(9)
{
    left: 55%;
    width: 90px;
    height: 90px;
    animation-delay: 4.5s;
} 
.boxarea li:nth-child(10)
{
    left: 35%;
    width: 145px;
    height: 145px;
    animation-delay: 7.5s;
} 
@keyframes animate{
    0%{
        transform: translateY(0) rotate(0deg);
        opacity: 1;
    }
    100%{
        transform: translateY(-800px) rotate(360deg);
        opacity: 0;
    }
}