.grayscale-img {
    transition: filter .3s ease-in-out;
    -webkit-filter: grayscale(100%); /* Ch 23+, Saf 6.0+, BB 10.0+ */
    filter: grayscale(100%); /* FF 35+ */
    width: 100%;
  }
  
  .grayscale-img:hover {
    -webkit-filter: grayscale(0%); /* Ch 23+, Saf 6.0+, BB 10.0+ */
    filter: grayscale(0%); /* FF 35+ */
  }