.arrow,
.arrow:before
{
    position: absolute;
    left: 50%

}

.arrow{

    width: 40px;
    height: 40px;
    top: 90%;
    margin: -20px 0 0 -20px;
    -webkit-transform: rotate(45deg);
    border-left: none;
    border-top: none;
    border-right: 4px #000000 solid;
    border-bottom: 4px rgb(0, 0, 0) solid;
}

  
.arrow:before
{
    content: '';
    width: 20px;
    height: 20px;
    top: 50%;
    margin: -10px 0 0 -10px;
    border-left: none;
    border-top: none;
    border-right: 2px rgb(0, 0, 0) solid;
    border-bottom: 2px rgb(0, 0, 0) solid;
    animation-duration: 2s;
    animation-iteration-count: infinite;
    animation-name: arrow;
}
  
@keyframes arrow
{
    0%
    {
        opacity: 1;
    }
    100%
    {
        opacity: 0;
        transform: translate(-10px, -10px);
    }
}