/* ========================================
   Right Preview Rail
   Vertical scroll indicator with clickable stops
   ======================================== */
.preview-rail {
  position: fixed;
  right: 1.5rem;
  top: 50%;
  transform: translateY(-50%);
  z-index: 90;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0;
  pointer-events: none;
}

/* Track */
.rail-track {
  position: relative;
  width: 2px;
  height: 50vh;
  background: var(--divider);
  border-radius: 1px;
  pointer-events: auto;
}

/* Fill — shows scroll progress */
.rail-fill {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 0%;
  background: var(--accent);
  border-radius: 1px;
  transition: height 0.08s linear;
  box-shadow: 0 0 8px rgba(0, 240, 255, 0.4);
}

/* Stops container */
.rail-stops {
  position: absolute;
  left: 0;
  top: 0;
  width: 2px;
  height: 50vh;
  pointer-events: auto;
}

/* Individual stop */
.rail-stop {
  position: absolute;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--bg-secondary);
  border: 2px solid var(--divider);
  cursor: pointer;
  transition: border-color var(--transition-base), background var(--transition-base), box-shadow var(--transition-base), transform var(--transition-base);
  z-index: 2;
}

.rail-stop:hover {
  border-color: var(--accent);
  transform: translate(-50%, -50%) scale(1.3);
}

.rail-stop.active {
  background: var(--accent);
  border-color: var(--accent);
  box-shadow: 0 0 0 4px rgba(0, 240, 255, 0.12), 0 0 16px rgba(0, 240, 255, 0.4);
  animation: railPulse 2s ease-in-out infinite;
}

/* Stop label (shown on hover) — positioned to the left of the rail */
.rail-stop-label {
  position: absolute;
  right: 20px;
  top: 50%;
  transform: translateY(-50%);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--text-secondary);
  white-space: nowrap;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-base), color var(--transition-base);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.rail-stop:hover .rail-stop-label,
.rail-stop.active .rail-stop-label {
  opacity: 1;
}

.rail-stop.active .rail-stop-label {
  color: var(--accent);
}

/* Pulse animation for active stop */
@keyframes railPulse {
  0%, 100% {
    box-shadow: 0 0 0 4px rgba(0, 240, 255, 0.12), 0 0 16px rgba(0, 240, 255, 0.4);
  }
  50% {
    box-shadow: 0 0 0 6px rgba(0, 240, 255, 0.08), 0 0 24px rgba(0, 240, 255, 0.6);
  }
}

/* Hide on mobile and tablet */
@media (max-width: 1024px) {
  .preview-rail {
    display: none;
  }
}