Бегущая пунктирная полоса сверху вниз

.twelve_txt_1:before {
    content: "";
    height: 400px;
    width: 1px;
    position: absolute;
    bottom: 0;
    outline: 1px solid transparent;
    background: linear-gradient(90deg, #C1FB78 50%, transparent 0) repeat-x, linear-gradient(0deg, #C1FB78 50%, transparent 0) repeat-y;
    background-size: 0 7px, 2px 25px;
    background-position: 0 0, 0 100%, 0 0, 100% 0;
    animation: linearGradientMove 7s infinite linear;
}
@keyframes linearGradientMove {
100% {
    background-position: 0 7%;
}
}