.btn-primary {
    -webkit-transform: perspective(1px) translateZ(0);
    transform: perspective(1px) translateZ(0);
    box-shadow: 0 0 1px rgba(0, 0, 0, 0);
    position: relative;
    -webkit-transition-property: color;
    transition-property: color;
    -webkit-transition-duration: 0.3s;
    transition-duration: 0.3s;
  }
  .btn-primary:before {
    content: "";
    position: absolute;
    z-index: -1;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: #fff;
    -webkit-transform: scaleX(0);
    transform: scaleX(0);
    -webkit-transform-origin: 0 50%;
    transform-origin: 0 50%;
    -webkit-transition-property: transform;
    transition-property: transform;
    -webkit-transition-duration: 0.3s;
    transition-duration: 0.3s;
    -webkit-transition-timing-function: ease-out;
    transition-timing-function: ease-out;
  }
  
  .btn-primary:hover:before, .btn-primary:focus:before, .btn-primary:active:before {
    -webkit-transform: scaleX(1);
    transform: scaleX(1);
  }