body {
  overflow: hidden;
}

.app {
  background: #000000;
  color: #fff;
  letter-spacing: 0.08rem;
  width: 100vw;
  height: 100vh;
  position: relative;
  overflow: hidden;
}
.core,
.content,
.nav,
.mask,
.labels,
.label {
  position: absolute;
  width: 100%;
  height: 100%;
  top: 0;
  left: 0;
}

.core {
  height: calc(100% - 300px);
}
.core img {
  position: absolute;
  top: 0;
  left: 30%;
  height: 100%;
  width: auto;
}
.core-layer {
  display: none;
}
.core-layer.selected {
  display: block;
  animation: fadeIn 1s;
}

.mask {
  width: 40%;
  left: 50%;
  margin-left: -20%;
  box-sizing: border-box;
  border-left: 5px solid rgba(0,0,0,0.5);
  border-right: 5px solid rgba(0,0,0,0.5);
  box-shadow: 0 20vh 10vh 10vh rgba(255, 255, 255, 0.1) inset;
  overflow: hidden;
}

.labels {
  width: 40%;
  top: 10%;
  height: 16.125%;
  left: 50%;
  box-sizing: border-box;
  margin-left: -20%;
  border-left: 5px solid rgba(60,60,60,0.5);
  border-right: 5px solid rgba(60,60,60,0.5);
  color: #8c9393;
  font-size: 1.4rem;
  line-height: 1.5;
}
.label {
  width: 400px;
  left: -420px;
  text-align: right;
}
.label span {
  font-size: 1.2rem;
}
.label.right {
  left: auto;
  right: -420px;
  text-align: left;

}

.content {
  height: 200px;
  top: auto;
  bottom: 100px;
  box-sizing: border-box;
  padding: 1rem 3rem;
  font-size: 1.3rem;
  line-height: 1.5;
}

.nav {
  height: 100px;
  top: auto;
  bottom: 0;
}
.nav button {
  display: block;
  float: left;
  width: 33.3333333%;
  height: 100px;
  line-height: 100px;
  text-align: center;
  border: none;
  font-size: 2rem;
  color: #fff;
  background: none;
  cursor: pointer;
  box-sizing: border-box;
  border-top: 2px solid #366b6d;
  /*border-bottom: 5px solid #366b6d;*/
}
.nav button.selected {
  background: #8ec7c9;
  color: #0f4446;
}
.nav button.selected:after {
  content: " ✓";
}

.red {
  color: #ff7676;
}
.orange {
  color: #ffaa00;
}
.yellow {
  color: #ffff00;
}
.green {
  color: #3fe053;
}

@keyframes fadeIn {
  from {
    opacity: 0;
  }

  to {
    opacity: 1;
  }
}