/* Shared navigation chrome for the static interactive tutorials.
   All rules are scoped under #pai-chrome so they cannot leak into — or be
   clobbered by — each tutorial's bespoke <style>. Light theme by default;
   dark theme applies only to the chrome when #pai-chrome[data-pai-theme="dark"].
   The tutorial body itself is intentionally left untouched. */

#pai-chrome,
#pai-chrome *,
#pai-chrome *::before,
#pai-chrome *::after {
  box-sizing: border-box;
}

#pai-chrome {
  /* Light theme tokens */
  --pai-bar-bg: rgba(255, 255, 255, 0.85);
  --pai-border: #e6e7ea;
  --pai-text: #1a1b20;
  --pai-text-muted: #52555e;
  --pai-hover-bg: rgba(0, 0, 0, 0.05);
  --pai-active-bg: rgba(0, 153, 238, 0.12);
  --pai-accent: #0099ee;
  --pai-sub-bg: rgba(255, 255, 255, 0.95);

  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica,
    Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
}

#pai-chrome[data-pai-theme="dark"] {
  --pai-bar-bg: rgba(14, 15, 18, 0.85);
  --pai-border: #2a2c33;
  --pai-text: #eeeef0;
  --pai-text-muted: #8b8e98;
  --pai-hover-bg: rgba(255, 255, 255, 0.07);
  --pai-active-bg: rgba(0, 153, 238, 0.18);
  --pai-accent: #0099ee;
  --pai-sub-bg: rgba(20, 22, 26, 0.95);
}

/* ---------- Top bar (sticky) ---------- */
#pai-chrome .pai-top {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--pai-bar-bg);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--pai-border);
  color: var(--pai-text);
}

#pai-chrome .pai-top-inner {
  max-width: 1280px;
  margin: 0 auto;
  height: 56px;
  padding: 0 16px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

#pai-chrome .pai-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 600;
  font-size: 15px;
  letter-spacing: -0.01em;
  color: var(--pai-text);
  text-decoration: none;
  white-space: nowrap;
  flex-shrink: 0;
}

#pai-chrome .pai-logo {
  width: 24px;
  height: 24px;
  border-radius: 8px;
  background: linear-gradient(135deg, #0061a2, #0099ee, #7c5cff);
  box-shadow: 0 2px 10px rgba(0, 153, 238, 0.35);
  display: grid;
  place-items: center;
  flex-shrink: 0;
}

#pai-chrome .pai-logo::after {
  content: "";
  width: 6px;
  height: 6px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.9);
}

#pai-chrome .pai-nav {
  display: flex;
  align-items: center;
  gap: 4px;
}

#pai-chrome .pai-link {
  display: inline-flex;
  align-items: center;
  padding: 8px 12px;
  border-radius: 8px;
  font-size: 14px;
  line-height: 1;
  white-space: nowrap;
  text-decoration: none;
  color: var(--pai-text-muted);
  transition: background-color 0.15s ease, color 0.15s ease;
}

#pai-chrome .pai-link:hover {
  background: var(--pai-hover-bg);
  color: var(--pai-text);
}

#pai-chrome .pai-link[aria-current="page"] {
  background: var(--pai-active-bg);
  color: var(--pai-accent);
  font-weight: 600;
}

#pai-chrome .pai-icon-btn {
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  border-radius: 8px;
  border: none;
  background: transparent;
  color: var(--pai-text-muted);
  cursor: pointer;
  transition: background-color 0.15s ease, color 0.15s ease;
}

#pai-chrome .pai-icon-btn:hover {
  background: var(--pai-hover-bg);
  color: var(--pai-text);
}

#pai-chrome .pai-mobile-controls {
  display: none;
  align-items: center;
  gap: 4px;
}

/* ---------- Mobile dropdown panel ---------- */
#pai-chrome .pai-mobile-panel {
  display: none;
  border-top: 1px solid var(--pai-border);
  background: var(--pai-sub-bg);
}

#pai-chrome .pai-mobile-panel.pai-open {
  display: block;
}

#pai-chrome .pai-mobile-list {
  list-style: none;
  margin: 0;
  padding: 8px;
  max-width: 1280px;
  margin: 0 auto;
}

#pai-chrome .pai-mobile-list a {
  display: flex;
  align-items: center;
  min-height: 44px;
  padding: 0 12px;
  border-radius: 8px;
  font-size: 16px;
  text-decoration: none;
  color: var(--pai-text-muted);
}

#pai-chrome .pai-mobile-list a:hover {
  background: var(--pai-hover-bg);
  color: var(--pai-text);
}

#pai-chrome .pai-mobile-list a[aria-current="page"] {
  background: var(--pai-active-bg);
  color: var(--pai-accent);
  font-weight: 600;
}

/* ---------- Context sub-bar ---------- */
#pai-chrome .pai-context {
  background: var(--pai-sub-bg);
  border-bottom: 1px solid var(--pai-border);
  color: var(--pai-text);
}

#pai-chrome .pai-context-inner {
  max-width: 1280px;
  margin: 0 auto;
  min-height: 48px;
  padding: 8px 16px;
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

#pai-chrome .pai-back {
  display: inline-flex;
  align-items: center;
  min-height: 36px;
  padding: 0 10px;
  border-radius: 8px;
  font-size: 13px;
  text-decoration: none;
  color: var(--pai-text-muted);
  flex-shrink: 0;
}

#pai-chrome .pai-back:hover {
  background: var(--pai-hover-bg);
  color: var(--pai-text);
}

#pai-chrome .pai-context-mid {
  display: flex;
  align-items: baseline;
  gap: 10px;
  min-width: 0;
  flex: 1 1 auto;
}

#pai-chrome .pai-series-title {
  font-size: 14px;
  font-weight: 600;
  color: var(--pai-text);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

#pai-chrome .pai-part {
  font-size: 12px;
  color: var(--pai-text-muted);
  white-space: nowrap;
  font-variant-numeric: tabular-nums;
}

#pai-chrome .pai-prevnext {
  display: flex;
  align-items: center;
  gap: 6px;
  flex-shrink: 0;
}

#pai-chrome .pai-step {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  min-height: 44px;
  min-width: 44px;
  justify-content: center;
  padding: 0 12px;
  border-radius: 8px;
  font-size: 13px;
  text-decoration: none;
  color: var(--pai-text-muted);
  border: 1px solid var(--pai-border);
  transition: background-color 0.15s ease, color 0.15s ease;
}

#pai-chrome .pai-step:hover {
  background: var(--pai-hover-bg);
  color: var(--pai-text);
}

#pai-chrome .pai-step[aria-disabled="true"] {
  opacity: 0.4;
  pointer-events: none;
}

/* ---------- Focus & motion ---------- */
#pai-chrome a:focus-visible,
#pai-chrome button:focus-visible {
  outline: 2px solid var(--pai-accent);
  outline-offset: 2px;
}

@media (prefers-reduced-motion: reduce) {
  #pai-chrome .pai-link,
  #pai-chrome .pai-icon-btn,
  #pai-chrome .pai-step {
    transition: none;
  }
}

/* ---------- Responsive ---------- */
@media (max-width: 720px) {
  #pai-chrome .pai-nav {
    display: none;
  }
  #pai-chrome .pai-mobile-controls {
    display: flex;
  }
}