/*effects*/
.btn-primary {
    position: relative;
    background: transparent;
    z-index: 2;
    border: 0;
    background: transparent!important;
    transition: color .3s;
}
.btn-primary:hover,
.btn-primary:focus {
    border: 0!important;
    background: transparent!important;
}
.btn-primary:hover::before,
.btn-primary:focus::before {
    box-shadow: inset 0 0 0 2px #000;
    -webkit-transform: scale3d(1.1, 1.1, 1);
    transform: scale3d(1.1, 1.1, 1);
}
.btn-primary::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border-radius: inherit;
    z-index: -1;
    box-shadow: inset 0 0 0 40px #000;
    -webkit-transform: scale3d(1, 1, 1);
    transform: scale3d(1, 1, 1);
    -webkit-transition: box-shadow 0.3s, -webkit-transform 0.3;
    transition: box-shadow 0.3s, transform 0.3s;
}