.hub {
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  padding-top: 5rem;
}

.hub-intro {
  text-align: center;
  padding: var(--space-xl) var(--content-padding) var(--space-lg);
}

.hub-intro h1 {
  margin-bottom: var(--space-sm);
}

.constellation {
  flex: 1;
  position: relative;
  margin: 0 var(--content-padding);
  min-height: 500px;
}

.constellation-lines {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
}

.connection-line {
  stroke: var(--color-border);
  stroke-width: 1;
  opacity: 0.4;
  transition: opacity var(--duration-normal) var(--ease-out);
}

.constellation:has(.zone-node:hover) .connection-line {
  opacity: 0.1;
}

.zone-node {
  position: absolute;
  left: var(--node-x);
  top: var(--node-y);
  transform: translate(-50%, -50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-sm);
  text-decoration: none;
  color: var(--color-muted);
  transition: all var(--duration-normal) var(--ease-out);
  z-index: 1;
}

.node-symbol {
  font-size: 2rem;
  color: var(--zone-color);
  transition: all var(--duration-normal) var(--ease-out);
  filter: drop-shadow(0 0 8px var(--zone-color));
  animation: pulse 3s ease-in-out infinite;
  animation-delay: calc(var(--stagger, 0) * 0.15s);
}

.node-label {
  font-family: var(--font-code);
  font-size: var(--text-xs);
  white-space: nowrap;
  opacity: 0.6;
  transition: opacity var(--duration-fast) var(--ease-out);
}

.node-glow {
  position: absolute;
  width: 120px;
  height: 120px;
  border-radius: 50%;
  background: radial-gradient(circle, var(--zone-color) 0%, transparent 70%);
  opacity: 0;
  transition: opacity var(--duration-normal) var(--ease-out);
  pointer-events: none;
  z-index: -1;
}

.zone-node:hover {
  text-decoration: none;
  transform: translate(-50%, -50%) scale(1.15);
}

.zone-node:hover .node-symbol {
  filter: drop-shadow(0 0 20px var(--zone-color));
  animation: none;
}

.zone-node:hover .node-label {
  opacity: 1;
  color: var(--color-text);
}

.zone-node:hover .node-glow {
  opacity: 0.15;
}

.constellation:has(.zone-node:hover) .zone-node:not(:hover) {
  opacity: 0.3;
}

.zone-node:focus-visible {
  outline: none;
}

.zone-node:focus-visible .node-symbol {
  outline: 2px solid var(--zone-color);
  outline-offset: 8px;
  border-radius: 4px;
}

.hub-stats {
  display: flex;
  justify-content: center;
  gap: var(--space-md);
  padding: var(--space-lg);
  font-family: var(--font-code);
  font-size: var(--text-sm);
  color: var(--color-muted);
}

@media (max-width: 768px) {
  .constellation {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-lg);
    padding: var(--space-lg);
    min-height: auto;
  }

  .constellation-lines {
    display: none;
  }

  .zone-node {
    position: static;
    transform: none;
    padding: var(--space-lg);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: 0.75rem;
  }

  .zone-node:hover {
    transform: translateY(-2px);
  }

  .node-glow {
    display: none;
  }

  .node-label {
    opacity: 1;
  }
}

/* ── Ambient Stars (Layer 1 / Task 5) ─────────────────── */
.ambient-bg--stars { background: transparent; }
.ambient-bg--stars .star {
  position: absolute; width: 2px; height: 2px; background: white; border-radius: 50%;
  animation: ambient-twinkle 3s ease-in-out infinite;
}

/* ── Visited-zone checkmarks (Layer 1 / Task 19) ─────── */
.zone-node--visited { box-shadow: 0 0 0 2px var(--zone-color, oklch(0.65 0.18 290)); }
.zone-check { position: absolute; top: 6px; right: 6px; color: var(--zone-color); font-weight: 800; }