.sombra_movil {
  -webkit-transform: translateZ(0);
}

.sombra_movil:hover {
  -webkit-transform: translateY(-6px);
  -webkit-animation: 1.5s movercaja infinite;
}

@-webkit-keyframes movercaja {
  50% {
    -webkit-transform: translateY(-3px);
  }
}

/* CODIGO DEL BEFORE */
.sombra_movil:before {
  position: absolute;
  content: '';
  top: 100%;
  left: 5%;
  height: 10px;
  width: 90%;
  opacity: 0;
  background: -webkit-radial-gradient(center, 
    ellipse,  rgba(0, 0, 0, 0.35) 0%, 
              rgba(0, 0, 0, 0) 80%);
  -webkit-transition-duration: 0.3s;
}

.sombra_movil:hover:before {
  opacity: 0.4;
  -webkit-transform: translateY(6px);
  -webkit-animation: 1.5s moversombra infinite;
}

@-webkit-keyframes moversombra {
  50% {
    -webkit-transform: translateY(3px);
    opacity: 1;
  }
}