$('.btn-7').addClass("light");   




  .light{
    overflow: hidden;
    z-index: 1;
    position: relative;
    -webkit-transition: 0.3s ease-out;
    transition: 0.3s ease-out;
    }
    .light:hover {
    -webkit-box-shadow: 0 5px 20px rgba(0, 0, 0, 0.5);
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.5);
    cursor: pointer;
    -webkit-transition-delay: 0.1s;
    transition-delay: 0.1s;
    color: #ffffff;
    z-index: 8;
}
    .light:before {
    content: "";
    background-color: rgba(255, 255, 255, 0.5);
    height: 100%;
    width: 3em;
    display: block;
    position: absolute;
    top: 0;
    left: -4.5em;
    -webkit-transform: skewX(-45deg) translateX(0);
    transform: skewX(-45deg) translateX(0);
    -webkit-transition: none;
    transition: none;
}    
    .light:hover:before {
    webkit-transform: skewX(-45deg) translateX(13.5em);
    transform: skewX(-45deg) translateX(22.5em);
    -webkit-transition: all 0.5s ease-in-out;
    transition: all 0.5s ease-in-out;
}