<button>Submit</button>

button {
  position: absolute;
  top: 50%;
  left: 50%;
  -webkit-transform: translate(-50%, -50%);
  -moz-transform: translate(-50%, -50%);
  -o-transform: translate(-50%, -50%);
  -ms-transform: translate(-50%, -50%);
  transform: translate(-50%, -50%);
  background: #1c222a;
  border: 0;
  line-height: 40px;
  padding: 0px 40px;
  -webkit-border-radius: 20px;
  border-radius: 20px;
  cursor: pointer;
  -webkit-transition: all 0.3s ease;
  -moz-transition: all 0.3s ease;
  -o-transition: all 0.3s ease;
  -ms-transition: all 0.3s ease;
  transition: all 0.3s ease;
  overflow: hidden;
  outline: none;
  font-family: 'Montserrat', sans-serif;
  font-weight: 700;
  text-transform: uppercase;
  font-size: 14px;
  color: #72d2ff;
}
button:hover:after {
  content: '';
  position: absolute;
  width: 200px;
  left: -200px;
  -webkit-transform: skewX(-20deg);
  -moz-transform: skewX(-20deg);
  -o-transform: skewX(-20deg);
  -ms-transform: skewX(-20deg);
  transform: skewX(-20deg);
  background-image: -webkit-linear-gradient(left, transparent, rgba(255,255,255,0.06), transparent);
  background-image: -moz-linear-gradient(left, transparent, rgba(255,255,255,0.06), transparent);
  background-image: -o-linear-gradient(left, transparent, rgba(255,255,255,0.06), transparent);
  background-image: -ms-linear-gradient(left, transparent, rgba(255,255,255,0.06), transparent);
  background-image: linear-gradient(to right, transparent, rgba(255,255,255,0.06), transparent);
  height: 50px;
  -webkit-animation: shine 0.7s ease;
  -moz-animation: shine 0.7s ease;
  -o-animation: shine 0.7s ease;
  -ms-animation: shine 0.7s ease;
  animation: shine 0.7s ease;
}
@-moz-keyframes shine {
  100% {
  left: 200px;
  }
}
@-webkit-keyframes shine {
  100% {
  left: 200px;
  }
}
@-o-keyframes shine {
  100% {
  left: 200px;
  }
}
@-ms-keyframes shine {
  100% {
  left: 200px;
  }
}
@keyframes shine {
  100% {
  left: 200px;
  }
}