#chapters {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 10;
  display: flex;
  flex-wrap: wrap;
  gap: 0;
  padding: 1rem 3vw 0;
  font-size: 0.5rem;
  pointer-events: none;
}

#chapters a:nth-child(n+3)::before {
  content: "·";
  color: var(--rule);
  margin: 0 0.6em;
  display: inline-block;
  text-decoration: none;
}

#chapters a {
  color: var(--muted);
  text-decoration: none;
  letter-spacing: 0.05em;
  pointer-events: auto;
  transition: color 100ms;
}

#chapters a:first-child {
  margin-right: auto;
}

#chapters a:hover,
#chapters a:focus-visible {
  color: var(--ink);
  outline: none;
}

#chapters a.active {
  color: var(--ink);
  font-weight: 600;
  text-decoration: underline;
  text-underline-offset: 0.35em;
  text-decoration-thickness: 1px;
}

footer {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  pointer-events: none;
  z-index: 10;
}

#page-number {
  position: absolute;
  right: 3vw;
  bottom: 3.5vh;
  font-size: 0.5rem;
  color: var(--muted);
  letter-spacing: 0.05em;
}

#progress {
  height: 5px;
  width: 100%;
  border-top: 1px solid var(--rule);
  background: transparent;
}

#progress-fill {
  height: 100%;
  width: 0;
  background: var(--ink);
  transition: width 120ms linear;
}