.no-exercise {
  opacity: 0;
}
.high-exercise {
  filter: opacity(0.83);
}
.medium-exercise {
  filter: opacity(0.75);
}
.low-exercise {
  filter: opacity(0.67);
}

#muscle-map {
  position: relative;
}
#muscle-map > #traps-a {
  top: 17.4%;
  left: 26.7%;
  width: 3.39%;
}
#muscle-map > #traps-b {
  top: 17.4%;
  left: 31.48%;
  width: 3.39%;
}
#muscle-map > #pecs {
  top: 22%;
  left: 24.3%;
  width: 13%;
}
#muscle-map > #shoulders-a {
  top: 21.1%;
  left: 21.84%;
  width: 5.61%;
}
#muscle-map > #shoulders-b {
  top: 21.1%;
  left: 34.1%;
  width: 5.61%;
}
#muscle-map > #biceps-a {
  top: 26.9%;
  left: 20.89%;
  width: 4.05%;
}
#muscle-map > #biceps-b {
  top: 26.9%;
  left: 36.67%;
  width: 4.05%;
}
#muscle-map > #forearm-a {
  top: 33.6%;
  left: 16.75%;
  width: 6.62%;
}
#muscle-map > #forearm-b {
  top: 33.6%;
  left: 38.18%;
  width: 6.61%;
}
#muscle-map > #obliques {
  top: 28.67%;
  left: 27.44%;
  width: 6.42%;
}
#muscle-map > #quads-b {
  top: 42.2%;
  left: 31.4%;
  width: 6.55%;
}
#muscle-map > #quads-a {
  top: 42.2%;
  left: 23.6%;
  width: 6.55%;
}
#muscle-map > #calves-a {
  top: 64.59%;
  left: 23.19%;
  width: 4.67%;
}
#muscle-map > #calves-b {
  top: 64.49%;
  left: 33.74%;
  width: 4.67%;
}
#muscle-map > #back-traps-a {
  top: 15.38%;
  left: 67.3%;
  width: 7%;
}
#muscle-map > #back-traps-b {
  top: 17.82%;
  left: 66.87%;
  width: 8.1%;
}
#muscle-map > #back-shoulders-a {
  top: 19.29%;
  left: 61.5%;
  width: 5.7%;
}
#muscle-map > #back-shoulders-b {
  top: 19.29%;
  left: 74.6%;
  width: 5.7%;
}
#muscle-map > #triceps-a {
  top: 24.83%;
  left: 60.2%;
  width: 4.58%;
}
#muscle-map > #triceps-b {
  top: 24.83%;
  left: 77.1%;
  width: 4.58%;
}
#muscle-map > #back-upper-a {
  top: 20.4%;
  left: 64.28%;
  width: 6.41%;
}
#muscle-map > #back-upper-b {
  top: 20.4%;
  left: 71.2%;
  width: 6.41%;
}
#muscle-map > #back-lats-a {
  top: 26.66%;
  left: 64.7%;
  width: 6%;
}
#muscle-map > #back-lats-b {
  top: 26.66%;
  left: 71.2%;
  width: 6%;
}
#muscle-map > #back-lower {
  top: 32.86%;
  left: 67.62%;
  width: 6.59%;
}
#muscle-map > #back-forearms-a {
  top: 33.5%;
  left: 56.1%;
  width: 6.36%;
}
#muscle-map > #back-forearms-b {
  top: 33.5%;
  left: 79.34%;
  width: 6.36%;
}
#muscle-map > #back-glutes {
  top: 41%;
  left: 64.89%;
  width: 12.08%;
}
#muscle-map > #back-hamstrings-a {
  top: 47.49%;
  left: 63.75%;
  width: 6.67%;
}
#muscle-map > #back-hamstrings-b {
  top: 47.49%;
  left: 71.47%;
  width: 6.7%;
}
#muscle-map > #back-calves-a {
  top: 64.43%;
  left: 61.94%;
  width: 4.8%;
}
#muscle-map > #back-calves-b {
  top: 64.43%;
  left: 75.1%;
  width: 4.8%;
}
#background {
  width: 100%;
  vertical-align: middle;
}
#muscle-map > img:not(#background) {
  display: block;
  position: absolute;
  transition: opacity 0.2s;
}