body,
html {
  height: 100%;
  margin: 0;
  padding: 0;
  width: 100%;
  background-color: #000000;
  overflow: hidden;
}
.container {
  height: calc(100% - 30px);
  width: 100%;
  text-align: center;
  overflow-y: auto;
}
.heading {
  background: black;
  color: white;
  align-items: center;
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 80px;
  animation: heading-animation 1.5s ease-out;
  z-index: 1000;
}
.heading div {
  position: absolute;
  top: calc(50% - 40px);
  left: 0;
  right: 0;
  text-align: center;
  align-items: center;
}
.heading img {
  height: 80px;
}

@keyframes heading-animation {
  0% {
    height: 100%;
  }
  60% {
    height: 100%;
  }
  100% {
    height: 80px;
  }
}

.main {
  margin-top: 80px;
  height: calc(50% - 80px);
  color: white;
  align-content: center;
  padding: 0 24px;
    min-height: 254px;
}

.separator {
  background: lightgray;
  display: inline-block;
  width: 100%;
  max-width: 700px;
  margin-top: 20px;
  margin-bottom: 20px;
  height: 2px;
}

.content {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
}
.nav-item {
  position: relative;
  align-content: center;
  background-color: #333333;
  padding: 11px;
  padding-left: 16px;
  color: white;
  font-weight: bold;
  text-decoration: underline;
  display: block;
  margin: 5px 5px;
}

.nav-item:hover {
  background-color: #555555;
  --color-nav: #3344ff;
}

.nav-item::before {
  content: " ";
  display: block;
  position: absolute;
  left: 0;
  top: 0;
  width: 3px;
  height: 100%;
  background-color: var(--color-nav);
}

.footer {
  height: 30px;
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  text-align: center;
}
.footer a {
  color: #aaaaaa;
}
.spoiler {
  color: #000000;
  background-color: #000000;
}