.collapse-arrow .arrow-icon {
  transform: rotate(90deg);
  transition: .3s transform ease-in-out;
  display: inline-block;
  margin-left: 20px;
}

.collapse-arrow .collapsed .arrow-icon {
  transform: rotate(0deg);
}

.collapse-arrow a{
    color: #3399cc;
}

.collapse-arrow a:hover{
    color: #fff;
}