/* ========================================
   THE ENGINE - INTERACTIVE DESIGN SYSTEM
   ======================================== */

/* ---- PAGE SHOW/HIDE ---- */
.page-hidden {
  display: none !important;
}

.page-active {
  display: block;
  animation: pageFadeIn 0.4s ease-out;
}
@keyframes pageFadeIn {
  from { opacity: 0; transform: translateY(16px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ---- READING PROGRESS BAR ---- */
.reading-progress {
  position: fixed;
  top: 0;
  left: 280px;
  right: 0;
  height: 2px;
  z-index: 91;
  background: transparent;
}

.reading-progress-fill {
  height: 100%;
  background: var(--accent, #c9a84c);
  transition: width 0.4s ease;
  width: 0;
  opacity: 0.5;
}

/* ---- NAV OVERRIDES (bigger, higher contrast) ---- */
nav a.section-head {
  font-size: 0.82rem !important;
  color: var(--accent, #c9a84c) !important;
  letter-spacing: 0.08em !important;
  padding: 0.55rem 1.5rem !important;
}
nav a.sub {
  font-size: 0.95rem !important;
  color: var(--text-secondary, #8a8478) !important;
  padding: 0.4rem 1.5rem 0.4rem 2.2rem !important;
}

nav a.sub:hover {
  color: var(--text-primary, #cec6bb) !important;
}

nav a.nav-active {
  color: var(--accent-glow, #e8c85a) !important;
  border-left: 3px solid var(--accent, #c9a84c) !important;
  background: var(--accent-bg, rgba(201, 168, 76, 0.06)) !important;
}

nav a.section-head.nav-active {
  color: var(--accent-glow, #e8c85a) !important;
}

/* ---- PAGE CONTROLS (prev/next) ---- */
.page-controls {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.2rem 0 0.8rem;
  margin-top: 1.2rem;
  border-top: 1px solid var(--border, rgba(201, 168, 76, 0.12));
}
.page-control-btn {
  background: var(--bg-surface, #12121e);
  border: 1px solid var(--border, rgba(201, 168, 76, 0.12));
  border-radius: 4px;
  padding: 0.6rem 1.2rem;
  font-family: 'Cinzel', serif;
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--text-secondary, #8a8478);
  cursor: pointer;
  transition: all 0.25s;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.page-control-btn:hover {
  background: var(--bg-elevated, #1a1a2a);
  color: var(--accent, #c9a84c);
  border-color: var(--accent-dim, #8b7530);
  transform: translateY(-1px);
}

.page-control-label { font-family: 'Crimson Pro', serif; font-size: 0.85rem; }
.page-indicator { font-family: 'JetBrains Mono', monospace; font-size: 0.7rem; color: var(--text-dim, #5a5650); letter-spacing: 0.15em; }

/* ---- MOBILE NAV ---- */
.mobile-nav-toggle {
  display: none; position: fixed; top: 0.7rem; left: 0.7rem; z-index: 200;
  background: var(--bg-surface, #12121e); border: 1px solid var(--border, rgba(201, 168, 76, 0.12));
  border-radius: 4px; padding: 0.55rem 0.6rem; cursor: pointer; flex-direction: column; gap: 4px;
}
.mobile-nav-toggle span {
  display: block; width: 18px; height: 1.5px;
  background: var(--text-secondary, #8a8478); transition: all 0.3s; border-radius: 1px;
}

.nav-overlay { display: none; position: fixed; inset: 0; background: rgba(0,0,0,0.6); z-index: 99; }

@media (max-width: 900px) {
  .mobile-nav-toggle { display: flex; }
  nav { display: block !important; transform: translateX(-100%); transition: transform 0.3s ease; z-index: 150; }
  .nav-open nav { transform: translateX(0); }
  .nav-open .nav-overlay { display: block; }
  .nav-open .mobile-nav-toggle span:nth-child(1) { transform: rotate(45deg) translate(4px, 4px); }
  .nav-open .mobile-nav-toggle span:nth-child(2) { opacity: 0; }
  .nav-open .mobile-nav-toggle span:nth-child(3) { transform: rotate(-45deg) translate(4px, -4px); }
  .reading-progress { left: 0; }
  .page-control-label { display: none; }
  .margin-note { display: none !important; }
  .margin-note-inline { display: block !important; }
}

/* =============================================
   INTERACTIVE PATTERNS
   ============================================= */

/* ---- SCROLL REVEAL ---- */
.reveal-on-scroll {
  opacity: 0; transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.reveal-on-scroll.revealed { opacity: 1; transform: translateY(0); }
.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }
/* ---- PULL QUOTE / KEY STATEMENT ---- */
.pull-quote {
  text-align: center; padding: 2.5rem 2rem 2rem; margin: 0 0 2.5rem; position: relative;
}
.pull-quote p {
  font-family: 'Cinzel', serif; font-size: 1.35rem; font-weight: 400;
  line-height: 1.55; color: var(--section-accent, var(--accent, #c9a84c));
  max-width: 640px; margin: 0 auto;
}
.pull-quote::after {
  content: ''; display: block; width: 60px; height: 1px;
  background: var(--section-accent, var(--accent, #c9a84c));
  margin: 2rem auto 0; opacity: 0.3;
}

/* ---- INLINE EXPANDER (Nutshell-inspired) ---- */
.expander-trigger {
  color: var(--section-accent, var(--accent, #c9a84c));
  border-bottom: 1.5px dotted var(--section-accent, var(--accent, #c9a84c));
  cursor: pointer; transition: all 0.2s; position: relative; padding-bottom: 1px;
}
.expander-trigger::after {
  content: ' +'; font-family: 'JetBrains Mono', monospace;
  font-size: 0.7em; opacity: 0.5; transition: transform 0.3s; display: inline-block;
}
.expander-trigger.open { border-bottom-style: solid; }
.expander-trigger.open::after { content: ' \2212'; opacity: 0.7; }
.expander-trigger:hover { color: var(--accent-glow, #e8c85a); border-bottom-color: var(--accent-glow, #e8c85a); }
.expander-body {
  max-height: 0; overflow: hidden;
  transition: max-height 0.5s cubic-bezier(0.25, 0.8, 0.25, 1), opacity 0.4s ease, padding 0.4s ease;
  opacity: 0; padding: 0 0 0 1.2rem; margin: 0;
  border-left: 2px solid transparent;
}
.expander-body.open {
  max-height: 2000px; opacity: 1;
  padding: 0.8rem 0 0.8rem 1.2rem; margin: 0.6rem 0 1rem;
  border-left-color: var(--section-accent, var(--accent-dim, #8b7530));
  background: rgba(255,255,255,0.015);
}
.expander-body p { font-size: 0.92rem; color: var(--text-secondary, #8a8478); line-height: 1.7; }
.expander-body p:last-child { margin-bottom: 0; }

/* ---- FLIP CARD ---- */
.flip-card-scene { perspective: 1200px; cursor: pointer; }
.flip-card-inner {
  position: relative; width: 100%; min-height: 200px;
  transform-style: preserve-3d; transition: transform 0.7s cubic-bezier(0.25, 0.8, 0.25, 1);
}
.flip-card-scene.flipped .flip-card-inner { transform: rotateY(180deg); }
.flip-card-face {
  position: absolute; inset: 0; backface-visibility: hidden; -webkit-backface-visibility: hidden;
  border-radius: 6px; padding: 1.8rem; border: 1px solid var(--border, rgba(201, 168, 76, 0.12));
}
.flip-card-front {
  background: var(--bg-surface, #12121e); display: flex; flex-direction: column; justify-content: center;
}
.flip-card-back {
  background: var(--bg-elevated, #1a1a2a); transform: rotateY(180deg);
  overflow-y: auto; border-color: var(--section-accent, var(--accent-dim, #8b7530));
}
.flip-card-front h4 { font-family: 'Cinzel', serif; font-size: 1.1rem; color: var(--section-accent, var(--accent, #c9a84c)); margin: 0 0 0.6rem; }
.flip-card-front .flip-summary { font-size: 0.88rem; color: var(--text-secondary); line-height: 1.6; }
.flip-card-front .flip-hint {
  font-family: 'JetBrains Mono', monospace; font-size: 0.6rem;
  color: var(--text-dim, #5a5650); letter-spacing: 0.15em;
  text-transform: uppercase; margin-top: auto; padding-top: 1rem;
}
.flip-card-back p { font-size: 0.9rem; color: var(--text-secondary, #8a8478); line-height: 1.7; }
.flip-card-back .flip-back-title {
  font-family: 'Cinzel', serif; font-size: 0.72rem; letter-spacing: 0.1em;
  text-transform: uppercase; color: var(--section-accent, var(--accent, #c9a84c)); margin-bottom: 0.8rem;
}

/* ---- PROGRESSIVE REVEAL ---- */
.progressive-reveal {
  background: var(--bg-surface, #12121e); border: 1px solid var(--border, rgba(201, 168, 76, 0.12));
  border-radius: 6px; overflow: hidden; margin: 2rem 0;
}
.progressive-steps {
  display: flex; border-bottom: 1px solid var(--border, rgba(201, 168, 76, 0.12));
  overflow-x: auto; scrollbar-width: none;
}
.progressive-steps::-webkit-scrollbar { display: none; }
.progressive-step-btn {
  flex: 1; min-width: 0; padding: 0.7rem 0.6rem; border: none; background: transparent;
  font-family: 'Cinzel', serif; font-size: 0.65rem; font-weight: 600;
  letter-spacing: 0.06em; text-transform: uppercase; color: var(--text-dim, #5a5650);
  cursor: pointer; transition: all 0.25s; white-space: nowrap; border-bottom: 2px solid transparent;
}
.progressive-step-btn.unlocked { color: var(--text-secondary, #8a8478); }
.progressive-step-btn.active {
  color: var(--section-accent, var(--accent, #c9a84c));
  border-bottom-color: var(--section-accent, var(--accent, #c9a84c));
  background: rgba(255,255,255,0.02);
}
.progressive-step-btn.locked { opacity: 0.3; cursor: not-allowed; }
.progressive-panel {
  padding: 2rem; display: none; animation: panelFadeIn 0.35s ease;
}
.progressive-panel.active { display: block; }
@keyframes panelFadeIn {
  from { opacity: 0; transform: translateX(10px); }
  to { opacity: 1; transform: translateX(0); }
}
.progressive-next {
  display: inline-flex; align-items: center; gap: 0.4rem;
  background: none; border: 1px solid var(--section-accent, var(--accent-dim, #8b7530));
  border-radius: 4px; padding: 0.5rem 1rem; font-family: 'Cinzel', serif;
  font-size: 0.72rem; letter-spacing: 0.06em;
  color: var(--section-accent, var(--accent, #c9a84c));
  cursor: pointer; transition: all 0.25s; margin-top: 1.2rem;
}
.progressive-next:hover { background: var(--accent-bg, rgba(201, 168, 76, 0.06)); transform: translateX(3px); }

/* ---- MARGIN NOTES (desktop right sidebar) ---- */
.margin-note {
  position: absolute; right: -240px; width: 210px;
  background: var(--bg-surface, #12121e); border: 1px solid var(--border, rgba(201, 168, 76, 0.12));
  border-radius: 4px; padding: 1rem; font-size: 0.8rem; line-height: 1.6;
  color: var(--text-dim, #5a5650); opacity: 0; transform: translateX(10px);
  transition: opacity 0.3s ease, transform 0.3s ease; pointer-events: none; z-index: 10;
}
.margin-note::before {
  content: ''; position: absolute; left: -20px; top: 1rem;
  width: 20px; height: 1px; background: var(--border, rgba(201, 168, 76, 0.12));
}
.margin-note.visible { opacity: 1; transform: translateX(0); pointer-events: auto; }
.margin-note .mn-label {
  font-family: 'JetBrains Mono', monospace; font-size: 0.6rem; letter-spacing: 0.12em;
  text-transform: uppercase; color: var(--section-accent, var(--accent-dim, #8b7530));
  margin-bottom: 0.5rem; display: block;
}
.margin-trigger {
  color: var(--text-primary, #cec6bb);
  border-bottom: 1px dashed var(--section-accent, var(--accent-dim, #8b7530));
  cursor: help; transition: color 0.2s;
}
.margin-trigger:hover { color: var(--section-accent, var(--accent, #c9a84c)); }
.margin-note-inline {
  display: none; background: var(--bg-surface, #12121e);
  border: 1px solid var(--border, rgba(201, 168, 76, 0.12));
  border-radius: 4px; padding: 0.8rem 1rem; margin: 0.8rem 0;
  font-size: 0.85rem; color: var(--text-dim, #5a5650);
}

/* ---- FEATURE GRID (for systems lists) ---- */
.feature-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 1rem; margin: 2rem 0;
}
.feature-card {
  background: var(--bg-surface, #12121e); border: 1px solid var(--border, rgba(201, 168, 76, 0.12));
  border-radius: 6px; padding: 1.2rem; transition: all 0.3s ease; cursor: default;
}
.feature-card:hover {
  border-color: var(--section-accent, var(--accent-dim, #8b7530));
  transform: translateY(-3px); box-shadow: 0 4px 20px rgba(0,0,0,0.2);
}
.feature-card strong {
  display: block; font-family: 'Cinzel', serif; font-size: 0.82rem;
  color: var(--section-accent, var(--accent, #c9a84c)); margin-bottom: 0.4rem;
}
.feature-card span { font-size: 0.85rem; color: var(--text-dim, #5a5650); line-height: 1.55; }

/* ---- PER-SECTION ACCENT THEMING ---- */
[data-accent="gold"]    { --section-accent: #c9a84c; --section-accent-dim: #8b7530; --section-accent-bg: rgba(201,168,76,0.06); }
[data-accent="amber"]   { --section-accent: #c98c4c; --section-accent-dim: #8b6530; --section-accent-bg: rgba(201,140,76,0.06); }
[data-accent="teal"]    { --section-accent: #4cb8a8; --section-accent-dim: #2a8a7a; --section-accent-bg: rgba(76,184,168,0.06); }
[data-accent="green"]   { --section-accent: #6aad6a; --section-accent-dim: #3a7a3a; --section-accent-bg: rgba(106,173,106,0.06); }
[data-accent="violet"]  { --section-accent: #9a7cc9; --section-accent-dim: #6a4f8b; --section-accent-bg: rgba(154,124,201,0.06); }
[data-accent="silver"]  { --section-accent: #9aa8b8; --section-accent-dim: #6a7888; --section-accent-bg: rgba(154,168,184,0.06); }
[data-accent="muted"]   { --section-accent: #8a8a7a; --section-accent-dim: #5a5a4a; --section-accent-bg: rgba(138,138,122,0.06); }
[data-accent="crimson"] { --section-accent: #c45050; --section-accent-dim: #8b2020; --section-accent-bg: rgba(196,80,80,0.06); }
/* Apply section accent to children */
[data-accent] h2 { color: var(--section-accent) !important; }
[data-accent] .section-num { color: var(--section-accent-dim, var(--section-accent)) !important; }
[data-accent] blockquote { border-left-color: var(--section-accent-dim) !important; }
[data-accent] blockquote strong { color: var(--section-accent) !important; }
[data-accent] .callout.philosophy { border-left-color: var(--section-accent) !important; }
[data-accent] .callout.technical { border-left-color: var(--section-accent) !important; }
[data-accent] .callout-label { color: var(--section-accent-dim) !important; }
[data-accent] li::marker { color: var(--section-accent-dim) !important; }
[data-accent] thead th { color: var(--section-accent) !important; }
[data-accent] .compare-card h4 { color: var(--section-accent) !important; }
[data-accent] .scenario-card .value { color: var(--section-accent) !important; }
[data-accent] .scenario-card .label { color: var(--section-accent-dim) !important; }

/* ---- SORTABLE TABLE HEADERS ---- */
.sortable-th {
  cursor: pointer; user-select: none; position: relative;
  padding-right: 1.5rem !important; transition: color 0.2s;
}
.sortable-th:hover { color: var(--accent-glow, #e8c85a) !important; }
.sortable-th::after {
  content: '\2195'; position: absolute; right: 0.3rem; top: 50%;
  transform: translateY(-50%); font-size: 0.65rem; opacity: 0.3;
}
.sortable-th.sort-asc::after { content: '\2191'; opacity: 0.8; }
.sortable-th.sort-desc::after { content: '\2193'; opacity: 0.8; }

/* ---- COLLAPSIBLE H3 SECTIONS ---- */
.collapsible-header {
  cursor: pointer; user-select: none; position: relative; padding-right: 2rem !important;
}
.collapsible-header::after {
  content: ''; position: absolute; right: 0; top: 50%;
  width: 8px; height: 8px;
  border-right: 1.5px solid var(--text-dim, #5a5650);
  border-bottom: 1.5px solid var(--text-dim, #5a5650);
  transform: translateY(-50%) rotate(45deg); transition: transform 0.25s ease, border-color 0.25s ease;
}
.collapsible-header.collapsed::after { transform: translateY(-50%) rotate(-45deg); }
.collapsible-header:hover { color: var(--section-accent, var(--accent, #c9a84c)) !important; }
.collapsible-header:hover::after { border-color: var(--section-accent, var(--accent, #c9a84c)); }
.collapsible-body { overflow: hidden; transition: max-height 0.45s cubic-bezier(0.25, 0.8, 0.25, 1), opacity 0.35s ease; }
.collapsible-open { max-height: 8000px; opacity: 1; }
.collapsible-closed { max-height: 0; opacity: 0; }

/* ---- HIGHLIGHTED TEXT ---- */
.text-accent { color: var(--section-accent, var(--accent, #c9a84c)); font-weight: 500; }

/* ---- CONTENT POSITIONING for margin notes ---- */
.content { position: relative; }


/* ---- ADDITIONAL PATTERNS ---- */

/* Flip hint text */
.flip-hint {
  display: block;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.6rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--section-accent, var(--accent, #c9a84c));
  opacity: 0.6;
  margin-top: 0.8rem;
  transition: opacity 0.3s ease;
}
.flip-card-scene:hover .flip-hint { opacity: 1; }

/* Compact flip cards for the gap grid */
.compact-flip {
  min-height: 140px;
}
.compact-flip .flip-card-front,
.compact-flip .flip-card-back {
  padding: 1.2rem;
  display: flex;
  flex-direction: column;
  justify-content: center;
}
.compact-flip .flip-card-front h4 {
  font-family: 'Cinzel', serif;
  font-size: 0.85rem;
  color: var(--section-accent, var(--accent, #c9a84c));
  margin: 0 0 0.4rem;
}
.compact-flip .flip-card-front p,
.compact-flip .flip-card-back p {
  font-size: 0.85rem;
  margin: 0;
}

/* Gap grid layout */
.gap-grid {
  grid-template-columns: repeat(4, 1fr) !important;
}
@media (max-width: 1100px) {
  .gap-grid { grid-template-columns: repeat(2, 1fr) !important; }
}
@media (max-width: 600px) {
  .gap-grid { grid-template-columns: 1fr !important; }
}

/* Scenario flip cards */
.scenario-flip {
  min-height: 180px;
  text-align: center;
}
.scenario-flip .flip-card-front,
.scenario-flip .flip-card-back {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  padding: 1.5rem;
}
.scenario-flip .label {
  font-family: 'Cinzel', serif;
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--section-accent, var(--accent-dim, #8b7530));
  margin-bottom: 0.6rem;
}
.scenario-flip .value {
  font-family: 'Cinzel', serif;
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--section-accent, var(--accent, #c9a84c));
  margin-bottom: 0.3rem;
}
.scenario-flip .desc {
  font-size: 0.82rem;
  color: var(--text-dim, #5a5650);
  font-style: italic;
}
.scenario-flip .flip-card-back p {
  font-size: 0.9rem;
  color: var(--text-secondary, #8a8478);
  text-align: center;
}

/* Scroll reveal on key elements */
blockquote,
.callout,
.thesis-block,
.pull-quote {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
blockquote.revealed,
.callout.revealed,
.thesis-block.revealed,
.pull-quote.revealed {
  opacity: 1;
  transform: translateY(0);
}


/* ---- MARGIN NOTE PANELS ---- */
.margin-note {
  position: relative;
  display: inline-block;
  margin: 0.8rem 0;
}
.margin-note-trigger {
  cursor: pointer;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--section-accent, var(--accent, #c9a84c));
  border-bottom: 1px dotted var(--section-accent, var(--accent-dim, #8b7530));
  padding-bottom: 1px;
  transition: color 0.2s;
}
.margin-note-trigger:hover {
  color: var(--accent-glow, #e8c85a);
}
.margin-note-panel {
  display: none;
  position: absolute;
  left: calc(100% + 2rem);
  top: -0.5rem;
  width: 220px;
  background: var(--bg-elevated, #1a1a2a);
  border: 1px solid var(--border, rgba(201,168,76,0.12));
  border-left: 3px solid var(--section-accent, var(--accent, #c9a84c));
  border-radius: 4px;
  padding: 1rem;
  z-index: 50;
  font-size: 0.82rem;
  line-height: 1.5;
  color: var(--text-secondary, #8a8478);
  box-shadow: 0 4px 20px rgba(0,0,0,0.3);
}
.margin-note-panel.visible { display: block; }
.margin-note-panel p { margin: 0; }


@media (max-width: 1100px) {
  .margin-note-panel {
    position: relative;
    left: 0;
    top: 0;
    width: 100%;
    margin-top: 0.5rem;
  }
}

/* ---- PROGRESSIVE REVEAL INDICATORS ---- */
.progressive-indicator {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1rem;
  padding-bottom: 0.8rem;
  border-bottom: 1px solid var(--border-subtle, rgba(255,255,255,0.04));
}
.progressive-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--bg-hover, #222238);
  border: 1px solid var(--border, rgba(201,168,76,0.12));
  transition: all 0.3s ease;
}
.progressive-dot.active {
  background: var(--section-accent, var(--accent, #c9a84c));
  border-color: var(--section-accent, var(--accent, #c9a84c));
  box-shadow: 0 0 8px rgba(201,168,76,0.3);
}
.progressive-step {
  transition: all 0.4s ease;
}
.progressive-visible {
  opacity: 1;
  max-height: 500px;
  margin-bottom: 0.8rem;
}
.progressive-locked {
  opacity: 0;
  max-height: 0;
  overflow: hidden;
  margin: 0;
}
.progressive-next {
  display: inline-block;
  background: transparent;
  border: 1px solid var(--section-accent, var(--accent-dim, #8b7530));
  color: var(--section-accent, var(--accent, #c9a84c));
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: 0.5rem 1.2rem;
  border-radius: 3px;
  cursor: pointer;
  transition: all 0.3s;
  margin-top: 0.5rem;
}
.progressive-next:hover {
  background: var(--accent-bg, rgba(201,168,76,0.06));
  border-color: var(--section-accent, var(--accent, #c9a84c));
}