button {
  width: 150px;
  height: 50px;
  border: 2px solid #000;
  font-family: 'Lato', sans-serif;
  font-size: 17px;
  text-decoration: none;
  text-transform: uppercase;
  letter-spacing: 2px;
  font-weight: 500;
  background: transparent;
  cursor: pointer;
  position: relative;
  display: inline-block;
  margin: 20px;
  outline: none;
  text-align: center;
  z-index: 2;
  transition: all 0.3s ease;
  overflow: hidden;
}

button::after {
  position: absolute;
  content: " ";
  z-index: -1;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  transition: all 0.3s ease;
}

button:hover {
  box-shadow: 4px 4px 6px 0 rgba(255,255,255,.5),
              -4px -4px 6px 0 rgba(116, 125, 136, .2), 
    inset -4px -4px 6px 0 rgba(255,255,255,.5),
    inset 4px 4px 6px 0 rgba(116, 125, 136, .3);
  color: #fff;
}

button:hover::after {
  transform: scale(2) rotate(180deg);
  background: #000;
  box-shadow: 4px 4px 6px 0 rgba(255,255,255,.5),
              -4px -4px 6px 0 rgba(116, 125, 136, .2), 
    inset -4px -4px 6px 0 rgba(255,255,255,.5),
    inset 4px 4px 6px 0 rgba(116, 125, 136, .3);
}