.shiny-btn4 {
    display: block;
    position: relative;
    width: 60%;/*ボタンの幅*/
    padding: 10px 0;
    margin: 30px auto;
    background-color: rgba(60, 174, 50, 0.7);/*ボタンの色*/
    box-shadow: 0 3px 0 0 rgba(60, 174, 50, 1);/*影の色(rgbaの値を変更)*/
    border-radius: 5px;
    font-weight: bold;
    font-size: 18px;
    color: #fff;
    text-align: center;
    text-decoration: none;
    overflow: hidden;
    transition: 0.2s;
}
.shiny-btn4:hover {
    text-decoration: none;
    color: #fff;
    box-shadow: none;
    -webkit-transform: translateY(3px);
}
.shiny-btn4::before {
    position: absolute;
    content: '';
    display: inline-block;
    top: -180px;
    left: 0;
    width: 30px;
    height: 100%;
    background-color: #fff;
    animation: shiny-btn4 3s ease-in-out infinite;
}
@-webkit-keyframes shiny-btn4 {
    0% { -webkit-transform: scale(0) rotate(45deg); opacity: 0; }
    80% { -webkit-transform: scale(0) rotate(45deg); opacity: 0.5; }
    81% { -webkit-transform: scale(4) rotate(45deg); opacity: 1; }
    100% { -webkit-transform: scale(50) rotate(45deg); opacity: 0; }
}