.button {
  touch-callout: none;
  -webkit-user-select: none;
     -moz-user-select: none;
      -ms-user-select: none;
          user-select: none;
  display: inline-block;
  border: .2em solid;
  position: relative;
  cursor: pointer;
  overflow: hidden;
  opacity: 0.6;
  color: #FFF;
}
.button__text {
  display: block;
  padding: 1em 2em;
  text-transform: uppercase;
  font-weight: bold;
}
.button__text:before {
  content: attr(title);
}
.button__text--bis {
  display: block;
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  -webkit-transform: translateX(-1em);
          transform: translateX(-1em);
  opacity: 0;
}
.button__mask {
  display: block;
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: white;
  -webkit-transform: translateX(-100%) rotate(45deg);
          transform: translateX(-100%) rotate(45deg);
  transition: all 0.3s;
}

.button:hover {
  opacity: 1;
}
.button:hover .button__text {
  -webkit-animation: fx-text .3s ease-out;
          animation: fx-text .3s ease-out;
}
.button:hover .button__text--bis {
  -webkit-animation: fx-text-bis .3s ease-out;
          animation: fx-text-bis .3s ease-out;
}
.button:hover .button__mask {
  -webkit-animation: fx-mask .3s ease-out;
          animation: fx-mask .3s ease-out;
}

.button:active {
  opacity: 1;
  background: white;
  color: inherit;
}

@-webkit-keyframes fx-mask {
  0% {
    -webkit-transform: translateX(-100%) rotate(45deg);
            transform: translateX(-100%) rotate(45deg);
  }
  100% {
    -webkit-transform: translateX(100%) rotate(45deg);
            transform: translateX(100%) rotate(45deg);
  }
}

@keyframes fx-mask {
  0% {
    -webkit-transform: translateX(-100%) rotate(45deg);
            transform: translateX(-100%) rotate(45deg);
  }
  100% {
    -webkit-transform: translateX(100%) rotate(45deg);
            transform: translateX(100%) rotate(45deg);
  }
}
@-webkit-keyframes fx-text {
  0% {
    -webkit-transform: translateX(0);
            transform: translateX(0);
    opacity: 1;
  }
  100% {
    -webkit-transform: translateX(1em);
            transform: translateX(1em);
    opacity: 0;
  }
}
@keyframes fx-text {
  0% {
    -webkit-transform: translateX(0);
            transform: translateX(0);
    opacity: 1;
  }
  100% {
    -webkit-transform: translateX(1em);
            transform: translateX(1em);
    opacity: 0;
  }
}
@-webkit-keyframes fx-text-bis {
  0% {
    -webkit-transform: translateX(-1em);
            transform: translateX(-1em);
    opacity: 0;
  }
  100% {
    -webkit-transform: translateX(0);
            transform: translateX(0);
    opacity: 1;
  }
}
@keyframes fx-text-bis {
  0% {
    -webkit-transform: translateX(-1em);
            transform: translateX(-1em);
    opacity: 0;
  }
  100% {
    -webkit-transform: translateX(0);
            transform: translateX(0);
    opacity: 1;
  }
}