/* ============================================================
   Step rail
   Sticky typographic index. A slim near-white bar marks the current
   step; completed steps remain available as jump targets.
   ============================================================ */

.rail {
  width: 238px;
  flex-shrink: 0;
  position: sticky;
  top: 0;
}

.rail__inner {
  display: flex;
  flex-direction: column;
  padding: var(--space-1) 0;
}

/* ---------- Step ---------- */

.rail__step {
  position: relative;
  display: grid;
  grid-template-columns: 32px minmax(0, 1fr);
  column-gap: var(--space-8);
  width: 100%;
  text-align: left;
  background: none;
  border: none;
  padding: 0 0 var(--space-10) var(--space-10);
  font: inherit;
  cursor: pointer;
}

.rail__step:last-child {
  padding-bottom: 0;
}

/* Steps you haven't reached yet aren't clickable */
.rail__step.is-locked {
  cursor: default;
}

.rail__step.is-locked .rail__label {
  color: var(--text-4);
}

.rail__step.is-locked .rail__sub {
  color: var(--text-5);
}

.rail__step:not(.is-locked):not(.is-current):hover .rail__label {
  color: var(--text);
}

.rail__step:not(.is-locked):not(.is-current):hover .rail__number {
  color: var(--text-2);
}

/* ---------- Current marker ---------- */

.rail__marker {
  position: absolute;
  top: 0;
  left: 0;
  width: 2px;
  height: 37px;
  border-radius: 1px;
  background: var(--select);
  opacity: 0;
  transition: opacity var(--dur) var(--ease);
}

.rail__step.is-current .rail__marker {
  opacity: 1;
}

/* ---------- Number and copy ---------- */

.rail__number {
  color: var(--text-4);
  font-family: var(--font-mono);
  font-size: var(--fs-base);
  font-feature-settings: 'tnum';
  line-height: var(--lh-relaxed);
  letter-spacing: var(--tracking-wide);
  transition: color var(--dur) var(--ease);
}

.rail__copy {
  min-width: 0;
}

.rail__step.is-done .rail__number {
  color: var(--text-3);
}

.rail__label {
  display: block;
  font-size: var(--fs-md);
  font-weight: var(--fw-regular);
  color: var(--text-3);
  line-height: var(--lh-snug);
  transition: color var(--dur) var(--ease);
}

.rail__step.is-done .rail__label {
  color: var(--text-2);
}

.rail__step.is-current .rail__number {
  color: var(--text-2);
}

.rail__step.is-current .rail__label {
  font-weight: var(--fw-medium);
  color: var(--text);
}

.rail__sub {
  display: block;
  font-size: var(--fs-sm);
  color: var(--text-4);
  line-height: var(--lh-relaxed);
  margin-top: var(--space-1);
}

.rail__step.is-current .rail__sub {
  color: var(--text-3);
}