.nav-show {
  padding: 1rem;
  background-color: #666;
  color: white;
  border: 1px solid white;
  position: fixed;
  top: 2vw;
  left: 2vw;
  font-size: 1.5rem;
  z-index: 3;
  border-radius: 0.2rem;
  opacity: 0;
  transition:
    opacity 0.5s ease,
    color 0.5s ease;
}

.nav-show:hover {
  cursor: pointer;
  color: #999;
}

.nav-show.show {
  opacity: 1;
}

nav {
  display: block;
  padding-left: 0.5em;
  position: fixed;
  left: -20vw;
  top: 0;
  height: 100vh;
  width: 20vw;
  transition: left 0.5s ease;
  z-index: 4;
  background-color: #000000cc;
  color: white;
  padding: 0.6rem;
}

nav.show {
  left: 0;
}

nav ul {
  border: 1px solid #aaa;
  height: calc(100vh - 2rem);
  list-style-type: none;
  display: flex;
  flex-direction: column;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
}

nav ul a li {
  font-family: sans-serif;
  font-weight: 100;
  font-style: italic;
  display: flex;
  justify-content: center;
  padding: 0.5em;
  transition:
    background-color 0.5s ease,
    color 0.5s ease;
  width: 5em;
}

nav ul a li:hover {
  /* background-color: var(--header-block-background); */
  background-color: #000;
  color: #777;
  cursor: pointer;
}

nav ul a {
  color: var(--std-colour);
  text-decoration: none;
}

nav ul li.active-link {
  background-color: #333;
  color: #999;
}

nav ul li.active-link:hover {
  cursor: default;
}

#close-nav {
  position: absolute;
  right: 3vw;
  top: 2vw;
  color: white;
  cursor: pointer;
  transition: color 0.5s ease;
}

#close-nav:hover {
  color: #999;
}

.nav-tree img {
  max-width: 5vw;
}

@media screen and (max-width: 900px) {
  nav {
    position: fixed;
    width: calc(100vw - 1rem);
    left: -100vw;
  }
  nav.show {
    left: 0;
  }
}