button {
  margin: 20px;
  outline: none;
}
.custom-btn {
  width: 430px;
  height: 40px;
  padding: 10px 25px;
  border: 2px solid #000;
  font-family: 'Lato', sans-serif;
  font-weight: 500;
  background: transparent;
  cursor: pointer;
  transition: all 0.3s ease;
  position: relative;
  display: inline-block;
}



/* 11 */
.btn-11 {
  overflow: hidden;
  transition: all 0.3s ease;
}
.btn-11:hover {
   background: #000;
  color: #fff;
}
.btn-11:before {
    position: absolute;
    content: '';
    display: inline-block;
    top: -180px;
    left: 0;
    width: 70%;
    height: 100%;
    background-color: #fff;
    animation: shiny-btn1 3s ease-in-out infinite;
}
.btn-11:active{
  box-shadow:  4px 4px 6px 0 rgba(255,255,255,.3),
              -4px -4px 6px 0 rgba(116, 125, 136, .2), 
    inset -4px -4px 6px 0 rgba(255,255,255,.2),
    inset 4px 4px 6px 0 rgba(0, 0, 0, .2);
}


@-webkit-keyframes shiny-btn1 {
    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; }
}