body {
  background-color: #323242;
  color: white;
  font-family: Arial, Verdana;
}

header {
  background-color: yellow;
  color: black;
  padding: 40px;
  text-align: center;
  font-size: 24px;
}

li {
  margin: 6px;
  padding: 6px;
}

.link-box {
  background-color: #eee;
  border-radius: 6px;
  padding: 6px;
  margin: 6px;
  text-decoration-line: none;
}

.link-box:hover {
  background-color: #ddf;
}

a img {
  filter: grayscale(25%);
}

a img:hover {
  filter: grayscale(0%);
  animation-duration: 120ms;
  animation-name: jiggle;
  animation-timing-function: ease-in;
  animation-iteration-count: 3;
}

@keyframes jiggle {
  0% {
    rotate: 0;
  }
  
  25% {
    rotate: -3deg;
  }
  
  50% {
    rotate: 0;
  }
  
  75% {
    rotate: 3deg;
  }
  
  100% {
    rotate: 0;
  }
}