/* ==========================================================================
   rail.css — the reading rail.
   A hairline down the left margin with one station per chapter. It draws in
   step with scroll position, so the page always says where you are without
   taking up a single pixel of content width. Desktop only.
   ========================================================================== */

.rail { display: none; }

@media (min-width: 1280px) {
  .rail {
    position: fixed;
    left: max(1.5rem, calc((100vw - var(--shell)) / 2 - 2.6rem));
    top: 50%;
    transform: translateY(-50%);
    z-index: 80;
    display: grid;
    gap: 0;
    padding-block: var(--s-2);
  }
}

.rail__line {
  position: absolute;
  left: 3px;
  top: 0; bottom: 0;
  width: 1px;
  background: rgba(243, 236, 221, 0.16);
  overflow: hidden;
}

.rail__line::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, var(--c-capital), var(--c-land), var(--c-table), var(--c-kunyit));
  transform: scaleY(var(--progress, 0));
  transform-origin: top;
  transition: transform 160ms linear;
}

.rail.on-husk .rail__line { background: rgba(43, 33, 20, 0.2); }

.rail__stop {
  position: relative;
  display: flex;
  align-items: center;
  gap: var(--s-4);
  padding-block: 0.62rem;
  color: var(--t-night-faint);
}
.rail.on-husk .rail__stop { color: var(--t-husk-faint); }

.rail__dot {
  width: 7px; height: 7px;
  border-radius: 50%;
  background: currentColor;
  flex: none;
  opacity: 0.5;
  transition: transform var(--d-mid) var(--e-spring), background var(--d-mid) var(--e-out), opacity var(--d-mid) var(--e-out);
}

.rail__name {
  font-family: var(--f-mono);
  font-size: 0.58rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  white-space: nowrap;
  opacity: 0;
  transform: translateX(-6px);
  transition: opacity var(--d-mid) var(--e-out), transform var(--d-mid) var(--e-out);
}

.rail__stop:hover .rail__name,
.rail__stop.is-current .rail__name { opacity: 1; transform: none; }

.rail__stop.is-current { color: var(--c-kunyit); }
.rail__stop.is-current .rail__dot { transform: scale(1.5); opacity: 1; }