/*effects*/
.btn {
    position: relative;
    overflow: hidden;
    z-index: 0;
}
.btn::before {
    content: '';
    opacity: 0.25;
    height: 100px;
    position: absolute;
    transform: translate3d(-120%, -50px, 0) rotate3d(0, 0, 1, 45deg);
    transition: all 1.1s cubic-bezier(0.19, 1, 0.22, 1);
    width: 200px;
    z-index: 1;
    top: 50%;
    left: 0;
}
.btn:hover::before {
    transform: translate3d(120%, -100px, 0) rotate3d(0, 0, 1, 90deg);
}