/* Sticky header: reading progress, brand and section links. */
.masthead {
  position: sticky;
  top: 0;
  z-index: 20;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  padding: 18px 3vw;
  border-bottom: 1px solid var(--ink);
  background: var(--paper);
}

.masthead__brand {
  font: 900 1.35rem var(--font-display);
  letter-spacing: -.04em;
}

.masthead__nav {
  display: flex;
  gap: 20px;
  justify-self: end;
  font: 10px var(--font-mono);
  text-transform: uppercase;
}

.masthead__album {
  padding: 0;
  border: 0;
  background: none;
  text-transform: inherit;
  opacity: .48;
  cursor: pointer;
}

.masthead__nav a:hover,
.masthead__album:hover {
  color: var(--red);
  opacity: 1;
}

html:not(.js) .masthead__album {
  display: none;
}

.progress {
  display: grid;
  grid-template-columns: 54px 1fr 30px;
  gap: 10px;
  align-items: center;
  width: min(220px, 24vw);
  padding: 0;
  border: 0;
  background: none;
  color: var(--ink);
  font: 10px var(--font-mono);
  text-align: left;
  cursor: pointer;
}

.progress:hover {
  color: var(--red);
}

.progress__rail {
  height: 2px;
  overflow: hidden;
  background: var(--soft);
}

.progress__fill {
  display: block;
  height: 100%;
  background: var(--red);
  transform: scaleX(var(--progress, 0));
  transform-origin: left;
  will-change: transform;
}

.progress__value {
  color: var(--muted);
  text-align: right;
}

@media (max-width: 820px) {
  .masthead {
    grid-template-columns: 1fr auto;
  }

  .masthead__nav {
    display: none;
  }

  .progress {
    grid-template-columns: 44px 1fr 26px;
    width: 150px;
  }
}