*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
body{
    background: #000;
    overflow: hidden;
    height: 100vh;

}
i{
    position: absolute;
    height: 200px;
    background: linear-gradient(transparent, #fff);
    border-bottom-left-radius: 5px;
    border-bottom-right-radius: 5px;
    animation: animate 5s linear infinite;
}
i:nth-child(3n + 1){
    background: linear-gradient(transparent, #0ff);
}
i:nth-child(3n + 2){
    background: linear-gradient(transparent, #0f0);
}
i:nth-child(3n + 3){
    background: linear-gradient(transparent, #f00);
}
@keyframes animate{
    0%{
        transform: translateY(-200px);
    }
    100%{
        transform: translateY(calc(100vh + 200px));
    }
}