.flow_step{
    height: 80%;
    position: relative;
}
.flow_step:after {
    content: '';
    position: absolute;
    width: 30px;
    height: 30px;
    border: solid 16px;
    border-color: #A30119 #A30119 transparent transparent;
    top: 47%;
    left: 47%;
    margin-left: -8px;
    transform: rotate(45deg);
}

.top-50 .flow_step:after {
    top: 50%;
}