* {
  padding: 0;
  margin: 0;
}
body {
  background: #f2f2f2;
  display: grid;
  height: 100vh;
  grid-template-rows: 40px 1fr 40px;
  row-gap: 20px;
}
img {
  max-width: 100%;
}
h1 {
  text-align: center;
  padding-block: 18px;
}

@media (max-width: 768px) {
  h1 {
    font-size: 1.5rem;
  }
}

.mask_container {
  margin-top: 2rem;
  width: 80vw;
  margin-inline: auto;
  position: relative;
}

.black_and_white_image {
}

.mask_image {
  position: absolute;
  inset: 0;
  background-image: url("assets/img/color\ image.jpg");
  background-size: contain;
  background-repeat: no-repeat;
  /* mask code */
  -webkit-mask-image: url("assets/img/mask\ Image.png");
  -webkit-mask-size: cover;
  -webkit-mask-position: 100% 0;
  -webkit-mask-repeat: no-repeat;
  mask-image: url("assets/img/mask\ Image.png");
  mask-size: cover;
  mask-repeat: no-repeat;
  mask-position: 100% 0%;
}

.mask_image:hover {
  animation: addColor 1500ms steps(32) forwards;
}

@keyframes addColor {
  0% {
    -webkit-mask-position: 100% 0%;
    mask-position: 100% 0%;
  }
  100% {
    -webkit-mask-position: 0% 0%;
    mask-position: 0% 0%;
  }
}

footer {
  display: flex;
  margin: 20px;
  align-items: center;
  justify-content: center;
}