.btn-primary-gradient {
    border: none;
    background-color: #90C95B;
    background-size: 200% 200%;
    background-position: top left;
    transition: all 0.5s;
}

.btn-primary-gradient:hover {
    background-position: bottom right;
    box-shadow: 0 .25rem .75rem #000000;
    box-shadow: 0 .25rem .75rem rgba(0, 0, 0, .05);
}