@mixin  button-tap($background: rgba(0, 0, 0, 0.87)) {
    @include transform(scale(1));
    position: absolute;
    background-color: $background;
    border-radius: 50%;
    box-sizing: content-box;
    width: 100%;
    height: 100%;
    opacity: 0;
    top:0;
    left:0;
    cursor: pointer;
}

.tap-active {
    opacity: 0.2 !important;
    @include transition(all, 0.25s, cubic-bezier(0.23, 1, 0.32, 1), 0ms);
    width: 100% !important;
    height: 100% !important;
    left: 0 !important;
    top:0 !important;
}