/**
 * Blockstate (blockstate) Design System Stylesheet & Multi-Edition Architecture
 * Aesthetic: Mechanical Interlocking & Archival Engineering
 * Edition I:   Warm Draughtsman Vellum (Default, [data-theme="vellum"] / :root)
 * Edition II:  Prussian Cyanotype Blueprint ([data-theme="cyanotype"])
 * Edition III: Swiss Constructivist Grid ([data-theme="swiss"])
 * Craft Standards:
 *   - R1: Zero Gradients (flat opaque surfaces, structural hairlines)
 *   - R2: Zero Glow (no neon box-shadows, zero blurry halos)
 *   - R3: Explicit Named Transitions (no transition: all)
 *   - R4: Anti-Monotony Typographic & Visual Rhythm
 *   - R5: No Placeholder Microcopy
 *   - R6: isolation: isolate for local stacking contexts
 *   - R7: Tuned Archival Neutrals (no pure black/white)
 *   - R8: 4px/8px Spatial Scale
 *   - R9: Typography Hierarchy & Tabular Numerals
 *   - R10: Hard Mechanical Offset Elevation (4px 4px 0px)
 *   - R11: Explicit Interactive States (:hover, :active, :focus-visible)
 *   - R12: Physics-Based Motion & Prefers-Reduced-Motion Support
 * Orthography: Strict British English
 * Intellectual Property: UK Patent Pending (Filed 28 Oct 2026, s.62(1) UK Patents Act 1977)
 * Licensing: Source-Available Dual Licence (LICENSE v1.0)
 */

/* ==========================================================================
   1. DESIGN TOKENS & MULTI-EDITION ARCHITECTURE
   ========================================================================== */

:root,
[data-theme="vellum"] {
  /* Edition I: 1965 Archival Vellum & Westinghouse Signal Box */
  --bg-canvas: #F4EFE6;
  --bg-surface: #FAF7F2;
  --bg-recessed: #EAE3D5;
  --bg-plate: #141413;

  --text-primary: #141413;
  --text-secondary: #3F3D39;
  --text-muted: #6B665E;
  --text-on-plate: #F4EFE6;
  --text-muted-on-plate: #A8A196;

  --border-strong: #141413;
  --border-subtle: #CFC7B8;
  --border-width-strong: 2px;
  --border-width-subtle: 1px;

  --shadow-mech: 4px 4px 0px #141413;
  --shadow-mech-sm: 2px 2px 0px #141413;
  --shadow-mech-lg: 6px 6px 0px #141413;
  --shadow-mech-hover: 5px 5px 0px #141413;
  --shadow-mech-active: 1px 1px 0px #141413;

  /* Authentic Westinghouse Lever Chromatics */
  --signal-vermilion: #D42B1E;
  --signal-vermilion-tint: #FCEAE8;
  --signal-cobalt: #0F3D7A;
  --signal-cobalt-tint: #E6EEF8;
  --signal-ochre: #B86B00;
  --signal-ochre-tint: #FDF3E3;
  --signal-brass: #8C6D2F;
  --signal-brass-bright: #C8A253;
  --signal-brass-tint: #F7F1E3;
  --signal-breach: #9E1B12;
  --signal-breach-tint: #FADCD9;

  /* Typography Stacks */
  --font-display: 'Fraunces', 'Baskerville', 'Instrument Serif', Georgia, serif;
  --font-heading: var(--font-display);
  --font-sans: 'IBM Plex Sans', 'Inter', 'Space Grotesk', system-ui, sans-serif;
  --font-mono: 'IBM Plex Mono', 'JetBrains Mono', Consolas, monospace;

  /* Type Scale */
  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 2rem;
  --text-4xl: 2.75rem;
  --text-5xl: 3.5rem;

  --leading-tight: 1.12;
  --leading-snug: 1.30;
  --leading-normal: 1.55;
  --leading-relaxed: 1.65;

  --tracking-tighter: -0.03em;
  --tracking-tight: -0.02em;
  --tracking-normal: 0em;
  --tracking-wide: 0.06em;
  --tracking-wider: 0.10em;

  /* Spatial Scale (Base 4px / 8px) */
  --space-0: 0px;
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;

  --radius-none: 0px;
  --radius-xs: 2px;
  --radius-sm: 4px;

  /* Stacking Contexts (Craft R6) */
  --z-base: 1;
  --z-sticky: 10;
  --z-dropdown: 20;
  --z-modal: 30;
  --z-toast: 40;

  /* Motion Physics (Craft R3 & R12) */
  --ease-mech-out: cubic-bezier(0.22, 1, 0.36, 1);
  --ease-mech-in: cubic-bezier(0.4, 0, 1, 1);
  --duration-fast: 120ms;
  --duration-base: 160ms;

  /* Semantic Compatibility Aliases */
  --color-bg-canvas: var(--bg-canvas);
  --color-bg-surface: var(--bg-surface);
  --color-bg-elevated: var(--bg-recessed);
  --color-border-rail: var(--border-strong);
  --color-border-subtle: var(--border-subtle);
  --color-border-strong: var(--border-strong);
  --color-text-primary: var(--text-primary);
  --color-text-secondary: var(--text-secondary);
  --color-text-muted: var(--text-muted);
  --color-text-subtle: var(--text-muted);
  --color-signal-clear: var(--signal-cobalt);
  --color-signal-caution: var(--signal-ochre);
  --color-signal-danger: var(--signal-vermilion);
  --color-signal-enclave: var(--signal-brass);
  --shadow-panel: var(--shadow-mech);

  --signal-clear-ink: var(--signal-cobalt);
  --signal-ochre-ink: var(--signal-ochre);
  --signal-vermilion-ink: var(--signal-vermilion);
  --signal-brass-ink: var(--signal-brass);
  --text-enamel-muted: var(--text-muted-on-plate);
  --tok-dec: var(--signal-brass-bright);
}

/* ==========================================================================
   EDITION II: 1920s FERRO-PRUSSIATE ENGINEERING BLUEPRINT ([data-theme="cyanotype"])
   ========================================================================== */
[data-theme="cyanotype"] {
  --bg-canvas: #0D2238;
  --bg-surface: #132D4A;
  --bg-recessed: #091829;
  --bg-plate: #071320;

  --text-primary: #F2F5F8;
  --text-secondary: #C4D4E5;
  --text-muted: #8AA6C4;
  --text-on-plate: #F2F5F8;
  --text-muted-on-plate: #8AA6C4;

  --border-strong: #F2F5F8;
  --border-subtle: #2A4F75;

  --shadow-mech: 4px 4px 0px #06101B;
  --shadow-mech-sm: 2px 2px 0px #06101B;
  --shadow-mech-lg: 6px 6px 0px #06101B;
  --shadow-mech-hover: 5px 5px 0px #06101B;
  --shadow-mech-active: 1px 1px 0px #06101B;

  --signal-vermilion: #E04632;
  --signal-vermilion-tint: #2B1A22;
  --signal-cobalt: #38BDF8;
  --signal-cobalt-alt: #5CE1E6;
  --signal-cyan: #38BDF8;
  --signal-cobalt-tint: #0E344A;
  --signal-ochre: #F0B429;
  --signal-ochre-tint: #2D2A1E;
  --signal-brass: #D4AF37;
  --signal-brass-bright: #F0B429;
  --signal-brass-tint: #28271E;
  --signal-breach: #FF5A47;
  --signal-breach-tint: #331820;

  --signal-clear-ink: #38BDF8;
  --signal-ochre-ink: #F0B429;
  --signal-vermilion-ink: #E04632;
  --signal-brass-ink: #D4AF37;
  --text-enamel-muted: #8AA6C4;
  --tok-dec: #F0B429;
}

/* ==========================================================================
   EDITION III: ULM SCHOOL / MULLER-BROCKMANN CONSTRUCTIVIST GRID ([data-theme="swiss"])
   ========================================================================== */
[data-theme="swiss"] {
  --bg-canvas: #F7F7F5;
  --bg-surface: #FFFFFF;
  --bg-recessed: #EBEBE6;
  --bg-plate: #111111;

  --text-primary: #111111;
  --text-secondary: #333333;
  --text-muted: #666666;
  --text-on-plate: #F7F7F5;
  --text-muted-on-plate: #A3A39E;

  --border-strong: #111111;
  --border-subtle: #D4D4CE;

  --shadow-mech: 4px 4px 0px #111111;
  --shadow-mech-sm: 2px 2px 0px #111111;
  --shadow-mech-lg: 6px 6px 0px #111111;
  --shadow-mech-hover: 5px 5px 0px #111111;
  --shadow-mech-active: 1px 1px 0px #111111;

  --signal-vermilion: #E11D48;
  --signal-vermilion-alt: #E62E25;
  --signal-crimson: #E11D48;
  --signal-vermilion-tint: #FCECEB;
  --signal-cobalt: #1436B8;
  --signal-cobalt-tint: #EAEFFA;
  --signal-ochre: #D97700;
  --signal-ochre-tint: #FDF2E4;
  --signal-brass: #735C24;
  --signal-brass-bright: #B8943C;
  --signal-brass-tint: #F4F0E6;
  --signal-breach: #B81414;
  --signal-breach-tint: #F9E5E5;

  --signal-clear-ink: #1436B8;
  --signal-ochre-ink: #D97700;
  --signal-vermilion-ink: #E11D48;
  --signal-brass-ink: #735C24;
  --text-enamel-muted: #A3A39E;
  --tok-dec: #B8943C;
}

/* ==========================================================================
   2. RESET & BASE ELEMENTS (Craft R6, R7, R8, R9)
   ========================================================================== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  background-color: var(--bg-canvas);
  color: var(--text-primary);
  font-family: var(--font-sans);
  line-height: var(--leading-relaxed);
  isolation: isolate;
  transition:
    background-color var(--duration-base) var(--ease-mech-out),
    color var(--duration-base) var(--ease-mech-out);
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  color: var(--text-primary);
  letter-spacing: var(--tracking-tight);
}

p {
  color: var(--text-secondary);
  line-height: var(--leading-relaxed);
}

a {
  color: var(--signal-cobalt);
  text-decoration: none;
  transition: color var(--duration-fast) var(--ease-mech-out);
}

a:hover {
  color: var(--signal-vermilion);
}

code, pre, .mono {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-variant-ligatures: none;
}

p code, li code, td code {
  background: var(--bg-recessed);
  border: 1px solid var(--border-subtle);
  padding: 0.12rem 0.38rem;
  border-radius: var(--radius-xs);
  font-size: 0.88em;
  color: var(--text-primary);
}

/* ==========================================================================
   3. TOP ARCHIVAL SPECIFICATION BAR & 3-EDITION SWITCHER
   ========================================================================== */
.top-signal-bar {
  background: var(--bg-plate);
  color: var(--text-on-plate);
  border-bottom: 1.5px solid var(--signal-brass-bright);
  padding: 0.4rem 0;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  isolation: isolate;
}

.top-signal-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
}

.signal-indicator {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  letter-spacing: var(--tracking-wide);
}

.signal-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--signal-vermilion);
  border: 1px solid #141413;
  display: inline-block;
  flex-shrink: 0;
}

.signal-dot.cobalt { background: var(--signal-cobalt); }
.signal-dot.crimson { background: var(--signal-vermilion); }
.signal-dot.amber { background: var(--signal-ochre); }

.edition-switcher {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
}

.edition-switcher-label {
  font-weight: 700;
  letter-spacing: var(--tracking-wide);
  color: var(--text-muted-on-plate);
  margin-right: 0.25rem;
}

.edition-btn {
  background: transparent;
  color: var(--text-on-plate);
  border: 1px solid var(--text-muted-on-plate);
  border-radius: var(--radius-xs);
  padding: 0.2rem 0.55rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: var(--tracking-wide);
  cursor: pointer;
  transition:
    background-color var(--duration-fast) var(--ease-mech-out),
    color var(--duration-fast) var(--ease-mech-out),
    border-color var(--duration-fast) var(--ease-mech-out);
}

.edition-btn:hover {
  background: rgba(255, 255, 255, 0.12);
  border-color: var(--text-on-plate);
}

.edition-btn:focus-visible {
  outline: 2px solid var(--signal-cobalt);
  outline-offset: 2px;
}

.edition-btn.active {
  background: var(--signal-vermilion);
  color: #FAF7F2;
  border-color: var(--signal-vermilion);
  font-weight: 700;
}

.top-signal-inner a {
  color: var(--text-muted-on-plate);
  font-size: var(--text-xs);
}

.top-signal-inner a:hover {
  color: var(--text-on-plate);
}

/* ==========================================================================
   4. MAIN SITE NAVIGATION (.site-header)
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  background: var(--bg-canvas);
  border-bottom: var(--border-width-strong) solid var(--border-strong);
  isolation: isolate;
}

.nav-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
  gap: 1.5rem;
}

.brand-logo {
  display: inline-flex;
  align-items: center;
  gap: 0.65rem;
  color: var(--text-primary);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.25rem;
  letter-spacing: var(--tracking-tight);
}

.brand-logo:hover {
  color: var(--text-primary);
}

.brand-badge {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 700;
  background: var(--bg-recessed);
  border: 1px solid var(--border-subtle);
  padding: 0.15rem 0.45rem;
  border-radius: var(--radius-xs);
  color: var(--text-muted);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-links a {
  color: var(--text-secondary);
  font-size: 0.875rem;
  font-weight: 600;
  padding: 0.35rem 0;
  border-bottom: 2px solid transparent;
  transition:
    color var(--duration-fast) var(--ease-mech-out),
    border-color var(--duration-fast) var(--ease-mech-out);
}

.nav-links a:hover {
  color: var(--text-primary);
}

.nav-links a.active,
.nav-links a[aria-current="page"] {
  color: var(--signal-cobalt);
  border-bottom-color: var(--signal-cobalt);
  font-weight: 700;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

/* ==========================================================================
   5. MECHANICAL LEVER BUTTONS (.btn)
   ========================================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: 0.65rem 1.25rem;
  background: var(--bg-surface);
  color: var(--text-primary);
  border: var(--border-width-strong) solid var(--border-strong);
  box-shadow: var(--shadow-mech);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-weight: 700;
  letter-spacing: var(--tracking-wide);
  text-transform: uppercase;
  text-decoration: none;
  cursor: pointer;
  border-radius: var(--radius-xs);
  line-height: 1.2;
  isolation: isolate;
  transition:
    transform var(--duration-fast) var(--ease-mech-out),
    box-shadow var(--duration-fast) var(--ease-mech-out),
    background-color var(--duration-fast) var(--ease-mech-out),
    color var(--duration-fast) var(--ease-mech-out);
}

.btn:hover {
  transform: translate(-1px, -1px);
  box-shadow: var(--shadow-mech-hover);
}

.btn:active {
  transform: translate(2px, 2px);
  box-shadow: var(--shadow-mech-active);
}

.btn:focus-visible {
  outline: 2px solid var(--signal-cobalt);
  outline-offset: 3px;
}

.btn-primary {
  background: var(--signal-vermilion);
  color: #FAF7F2;
  border-color: var(--border-strong);
}

.btn-primary:hover {
  background: #BF261A;
  color: #FAF7F2;
}

.btn-secondary {
  background: var(--bg-surface);
  color: var(--text-primary);
  border-color: var(--border-strong);
}

.btn-secondary:hover {
  background: var(--bg-recessed);
  color: var(--text-primary);
}

.btn-cobalt {
  background: var(--signal-cobalt);
  color: #FAF7F2;
  border-color: var(--border-strong);
}

.btn-cobalt:hover {
  background: #0B2C59;
  color: #FAF7F2;
}

.btn-amber {
  background: var(--signal-ochre);
  color: #FAF7F2;
  border-color: var(--border-strong);
}

.btn-amber:hover {
  background: #965700;
  color: #FAF7F2;
}

.btn-danger {
  background: var(--signal-breach);
  color: #FAF7F2;
  border-color: var(--border-strong);
}

.btn-danger:hover {
  background: #7F140D;
  color: #FAF7F2;
}

.btn-sm {
  padding: 0.4rem 0.8rem;
  font-size: 0.78rem;
}

/* ==========================================================================
   6. DRAWING TITLE SHEET & HERO SECTION
   ========================================================================== */
.hero {
  padding: var(--space-8) 0 var(--space-12);
  border-bottom: var(--border-width-strong) solid var(--border-strong);
  background: var(--bg-canvas);
  isolation: isolate;
}

.drawing-title-sheet {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  background: var(--bg-surface);
  border: var(--border-width-strong) solid var(--border-strong);
  border-bottom: none;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: var(--tracking-wide);
  color: var(--text-primary);
  text-transform: uppercase;
}

.drawing-stamp-brass {
  color: var(--signal-brass);
  font-weight: 700;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: var(--space-8);
  align-items: start;
  background: var(--bg-surface);
  border: var(--border-width-strong) solid var(--border-strong);
  padding: var(--space-8);
  box-shadow: var(--shadow-mech);
}

.section-eyebrow {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: var(--tracking-wider);
  color: var(--signal-cobalt);
  margin-bottom: var(--space-2);
}

.section-eyebrow.crimson { color: var(--signal-vermilion); }
.section-eyebrow.cyan { color: var(--signal-cobalt); }

.hero h1 {
  font-family: var(--font-display);
  font-size: clamp(2rem, 3.2vw, 2.75rem);
  font-weight: 700;
  line-height: var(--leading-tight);
  letter-spacing: var(--tracking-tight);
  color: var(--text-primary);
  margin-bottom: var(--space-4);
}

.hero-subtitle, .lead {
  font-size: var(--text-lg);
  line-height: var(--leading-relaxed);
  color: var(--text-secondary);
  margin-bottom: var(--space-5);
}

.railway-callout {
  background: var(--bg-recessed);
  border-left: 4px solid var(--signal-cobalt);
  border-top: 1px solid var(--border-subtle);
  border-right: 1px solid var(--border-subtle);
  border-bottom: 1px solid var(--border-subtle);
  padding: var(--space-4) var(--space-5);
  font-size: var(--text-sm);
  line-height: var(--leading-normal);
  color: var(--text-secondary);
  margin-bottom: var(--space-6);
}

.hero-cta-group {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  margin-top: var(--space-6);
}

/* ==========================================================================
   7. DUAL-AUDIENCE NAVIGATION FORK (ABOVE THE FOLD)
   ========================================================================== */
.dual-fork-strip {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-6);
  margin-top: var(--space-6);
}

.fork-card {
  background: var(--bg-surface);
  border: var(--border-width-strong) solid var(--border-strong);
  padding: var(--space-5);
  box-shadow: var(--shadow-mech-sm);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  isolation: isolate;
}

.fork-card-dev {
  border-top: 5px solid var(--signal-cobalt);
}

.fork-card-enterprise {
  border-top: 5px solid var(--signal-brass);
}

.fork-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.fork-badge {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: var(--tracking-wide);
  padding: 0.15rem 0.5rem;
  border-radius: var(--radius-xs);
  border: 1px solid var(--border-strong);
}

.badge-dev {
  background: var(--signal-cobalt-tint);
  color: var(--signal-cobalt);
  border-color: var(--signal-cobalt);
}

.badge-enterprise {
  background: var(--signal-brass-tint);
  color: var(--signal-brass);
  border-color: var(--signal-brass);
}

.fork-meta {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-muted);
}

.fork-title {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 700;
  color: var(--text-primary);
  margin: 0;
}

.fork-desc {
  font-size: var(--text-sm);
  line-height: var(--leading-normal);
  color: var(--text-secondary);
  flex: 1;
}

.fork-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-top: auto;
}

/* ==========================================================================
   8. INSTALL WIDGET (pip / uv Switcher)
   ========================================================================== */
.install-widget {
  background: var(--bg-surface);
  border: var(--border-width-strong) solid var(--border-strong);
  box-shadow: var(--shadow-mech-sm);
  margin-bottom: var(--space-5);
  isolation: isolate;
}

.install-tabs {
  display: flex;
  background: var(--bg-recessed);
  border-bottom: var(--border-width-strong) solid var(--border-strong);
  overflow-x: auto;
}

.install-tab {
  background: transparent;
  border: none;
  border-right: 1px solid var(--border-subtle);
  padding: var(--space-2) var(--space-4);
  font-family: var(--font-mono);
  font-size: 0.76rem;
  font-weight: 700;
  color: var(--text-secondary);
  cursor: pointer;
  white-space: nowrap;
  transition:
    background-color var(--duration-fast) var(--ease-mech-out),
    color var(--duration-fast) var(--ease-mech-out);
}

.install-tab:hover {
  background: rgba(0, 0, 0, 0.04);
  color: var(--text-primary);
}

.install-tab.active {
  background: var(--bg-surface);
  color: var(--signal-cobalt);
  border-bottom: 2px solid var(--signal-cobalt);
}

.install-cmd-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.65rem var(--space-4);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--text-primary);
  background: var(--bg-surface);
}

/* ==========================================================================
   9. TERMINAL WINDOWS (Cast-Iron Enamel Plates)
   ========================================================================== */
.terminal-window {
  background: var(--bg-plate);
  color: var(--text-on-plate);
  border: var(--border-width-strong) solid var(--border-strong);
  box-shadow: var(--shadow-mech);
  font-family: var(--font-mono);
  font-variant-ligatures: none;
  font-variant-numeric: tabular-nums;
  overflow: hidden;
  isolation: isolate;
}

.terminal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-2) var(--space-4);
  background: #1A1A18;
  border-bottom: 1.5px solid var(--signal-brass-bright);
  font-size: var(--text-xs);
  letter-spacing: var(--tracking-wide);
  text-transform: uppercase;
  color: var(--text-on-plate);
}

.terminal-dots {
  display: flex;
  gap: 6px;
  align-items: center;
}

.terminal-dot {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  display: inline-block;
}

.terminal-dot.red { background: var(--signal-vermilion); }
.terminal-dot.amber { background: var(--signal-ochre); }
.terminal-dot.green { background: #15803D; }

.terminal-title {
  font-weight: 700;
  color: var(--text-on-plate);
}

.terminal-status-badge {
  font-size: 0.7rem;
  font-weight: 700;
  padding: 0.15rem 0.45rem;
  border-radius: var(--radius-xs);
  border: 1px solid transparent;
}

.terminal-status-badge.status-ok {
  background: rgba(15, 61, 122, 0.4);
  color: #FAF7F2;
  border-color: var(--signal-cobalt);
}

.terminal-status-badge.status-fail {
  background: rgba(212, 43, 30, 0.4);
  color: #FAF7F2;
  border-color: var(--signal-vermilion);
}

.terminal-status-badge.status-warn {
  background: rgba(184, 107, 0, 0.4);
  color: #FAF7F2;
  border-color: var(--signal-ochre);
}

.terminal-body {
  padding: var(--space-4);
  font-size: 0.82rem;
  line-height: var(--leading-normal);
  overflow-x: auto;
  color: var(--text-on-plate);
  margin: 0;
  background: var(--bg-plate);
}

/* Syntax Tokens */
.tok-kw { color: #7DD3FC; font-weight: 600; }
.tok-dec { color: var(--signal-brass-bright); }
.tok-fn { color: #BAE6FD; font-weight: 600; }
.tok-str { color: #86EFAC; }
.tok-cmt { color: var(--text-muted-on-plate); font-style: italic; }
.tok-ok { color: #38BDF8; font-weight: 700; }
.tok-err { color: #F87171; font-weight: 700; }
.tok-typ { color: #FCD34D; font-weight: 600; }

/* ==========================================================================
   10. METRICS STRIP
   ========================================================================== */
.metrics-strip {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-4);
  margin-top: var(--space-6);
}

.metric-card {
  background: var(--bg-surface);
  border: var(--border-width-strong) solid var(--border-strong);
  padding: var(--space-4);
  box-shadow: var(--shadow-mech-sm);
  isolation: isolate;
}

.metric-spec-id {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: var(--tracking-wide);
  color: var(--text-muted);
  display: block;
  margin-bottom: var(--space-1);
}

.metric-value {
  font-family: var(--font-mono);
  font-size: 1.85rem;
  font-weight: 700;
  line-height: 1.1;
  color: var(--text-primary);
  margin-bottom: var(--space-1);
}

.metric-value.cyan { color: var(--signal-cobalt); }
.metric-value.amber { color: var(--signal-ochre); }

.metric-label {
  font-size: var(--text-xs);
  color: var(--text-secondary);
  line-height: var(--leading-normal);
}

/* ==========================================================================
   11. WESTINGHOUSE MECHANICAL SIGNAL BOX SIMULATOR
   ========================================================================== */
.simulator-shell {
  background: var(--bg-surface);
  border: var(--border-width-strong) solid var(--border-strong);
  box-shadow: var(--shadow-mech-lg);
  overflow: hidden;
  isolation: isolate;
  margin-top: var(--space-6);
}

.signal-box-nameplate {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-4);
  padding: var(--space-3) var(--space-5);
  background: var(--bg-plate);
  color: var(--text-on-plate);
  border-bottom: 2px solid var(--signal-brass-bright);
}

.nameplate-title-group {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
}

.nameplate-brass-tag {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--signal-brass-bright);
  letter-spacing: var(--tracking-wider);
}

.nameplate-heading {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 700;
  color: var(--text-on-plate);
  letter-spacing: var(--tracking-tight);
}

.tappet-interlock-status {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 700;
  padding: 0.3rem 0.65rem;
  border: 1.5px solid var(--signal-cobalt);
  background: rgba(15, 61, 122, 0.35);
  color: #FAF7F2;
  border-radius: var(--radius-xs);
  letter-spacing: var(--tracking-wide);
}

.tappet-interlock-status.breach {
  background: rgba(212, 43, 30, 0.45);
  border-color: var(--signal-vermilion);
  color: #FAF7F2;
}

.tappet-interlock-status.detour {
  background: rgba(184, 107, 0, 0.45);
  border-color: var(--signal-ochre);
  color: #FAF7F2;
}

.lever-frame-bay {
  padding: var(--space-5);
  background: var(--bg-recessed);
  border-bottom: var(--border-width-strong) solid var(--border-strong);
}

.lever-frame-header {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--text-secondary);
  margin-bottom: var(--space-4);
}

.lever-rack-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-4);
}

.lever-unit {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  padding: var(--space-4);
  background: var(--bg-surface);
  border: var(--border-width-strong) solid var(--border-strong);
  box-shadow: var(--shadow-mech);
  cursor: pointer;
  text-align: left;
  border-radius: var(--radius-xs);
  transition:
    transform var(--duration-fast) var(--ease-mech-out),
    box-shadow var(--duration-fast) var(--ease-mech-out),
    border-color var(--duration-fast) var(--ease-mech-out);
}

.lever-unit:hover {
  transform: translate(-1px, -1px);
  box-shadow: var(--shadow-mech-hover);
}

.lever-unit:active {
  transform: translate(2px, 2px);
  box-shadow: var(--shadow-mech-active);
}

.lever-unit:focus-visible {
  outline: 2px solid var(--signal-cobalt);
  outline-offset: 3px;
}

.lever-unit.pulled {
  border-color: var(--signal-vermilion);
  box-shadow: var(--shadow-mech-sm);
}

.lever-unit[data-lever-colour="cobalt"].pulled {
  border-color: var(--signal-cobalt);
}

.lever-unit[data-lever-colour="ochre"].pulled {
  border-color: var(--signal-ochre);
}

.lever-top-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-3);
}

.lever-brass-plate {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--signal-brass);
}

.lever-state-pill {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  font-weight: 700;
  padding: 0.15rem 0.4rem;
  border-radius: var(--radius-xs);
  background: var(--bg-recessed);
  border: 1px solid var(--border-subtle);
  color: var(--text-primary);
}

.lever-quadrant-slot {
  position: relative;
  height: 72px;
  background: var(--bg-recessed);
  border: 1.5px solid var(--border-strong);
  margin-bottom: var(--space-3);
  overflow: hidden;
}

.lever-quadrant-rail {
  position: absolute;
  top: 50%;
  left: 10%;
  right: 10%;
  height: 3px;
  background: var(--border-strong);
  transform: translateY(-50%);
}

.lever-shaft {
  position: absolute;
  top: 8px;
  bottom: 8px;
  left: 22%;
  width: 14px;
  background: var(--border-strong);
  border-radius: var(--radius-xs);
  transition:
    left var(--duration-base) var(--ease-mech-out),
    background-color var(--duration-base) var(--ease-mech-out);
}

.lever-unit.pulled .lever-shaft {
  left: 70%;
}

.lever-unit[data-lever-colour="cobalt"] .lever-shaft { background: var(--signal-cobalt); }
.lever-unit[data-lever-colour="vermilion"] .lever-shaft { background: var(--signal-vermilion); }
.lever-unit[data-lever-colour="ochre"] .lever-shaft { background: var(--signal-ochre); }

.lever-title {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 700;
  margin-bottom: var(--space-1);
  color: var(--text-primary);
}

.lever-desc {
  font-size: 0.76rem;
  color: var(--text-secondary);
  line-height: var(--leading-normal);
}

/* Simulator Tabs */
.simulator-tabs {
  display: flex;
  border-bottom: var(--border-width-strong) solid var(--border-strong);
  background: var(--bg-canvas);
}

.sim-tab-btn {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-4);
  background: transparent;
  border: none;
  border-right: 1.5px solid var(--border-strong);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--text-secondary);
  cursor: pointer;
  transition:
    background-color var(--duration-fast) var(--ease-mech-out),
    color var(--duration-fast) var(--ease-mech-out);
}

.sim-tab-btn:last-child {
  border-right: none;
}

.sim-tab-btn:hover {
  background: var(--bg-recessed);
  color: var(--text-primary);
}

.sim-tab-btn.active {
  background: var(--bg-surface);
  color: var(--text-primary);
  border-bottom: 3px solid var(--signal-cobalt);
}

.sim-panel {
  display: none;
  padding: var(--space-6);
}

.sim-panel.active {
  display: block;
}

.sim-control-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-5);
}

.sim-workspace-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-6);
  align-items: start;
}

/* ==========================================================================
   12. SVG CANVAS & CONTROL FLOW GRAPH
   ========================================================================== */
.svg-canvas-box {
  background: var(--bg-canvas);
  border: 1.5px solid var(--border-strong);
  box-shadow: var(--shadow-mech-sm);
  padding: var(--space-4);
}

.cfg-svg {
  width: 100%;
  height: auto;
  display: block;
}

.svg-edge {
  stroke: var(--border-strong);
  stroke-width: 2px;
  fill: none;
}

.svg-edge.edge-verified {
  stroke: var(--signal-cobalt);
  stroke-width: 2.5px;
}

.svg-edge.edge-bypass {
  stroke: var(--signal-vermilion);
  stroke-width: 2.5px;
  stroke-dasharray: 4 4;
}

.svg-node rect {
  fill: var(--bg-surface);
  stroke: var(--border-strong);
  stroke-width: 1.5px;
}

.svg-node text {
  fill: var(--text-primary);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
}

.svg-node .node-subtext {
  fill: var(--text-muted);
  font-size: 9px;
  font-weight: 400;
}

.node-precursor rect {
  fill: var(--signal-cobalt-tint);
  stroke: var(--signal-cobalt);
  stroke-width: 2px;
}

.node-verified rect {
  fill: var(--bg-surface);
  stroke: var(--signal-cobalt);
  stroke-width: 2px;
}

.node-violated rect {
  fill: var(--signal-breach-tint);
  stroke: var(--signal-vermilion);
  stroke-width: 2px;
}

/* ==========================================================================
   13. DISPATCH TABLE & TASKSTACK STEPPER
   ========================================================================== */
.dispatch-table-card {
  background: var(--bg-canvas);
  border: 1.5px solid var(--border-strong);
  padding: var(--space-4);
  margin-bottom: var(--space-4);
  box-shadow: var(--shadow-mech-sm);
}

.dispatch-slot-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.5rem 0.75rem;
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-xs);
  margin-bottom: 0.35rem;
  font-family: var(--font-mono);
  font-size: 0.78rem;
}

.dispatch-slot-row.present {
  border-left: 3px solid var(--signal-cobalt);
}

.dispatch-slot-row.absent {
  border-left: 3px solid var(--signal-vermilion);
}

.stepper-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-3);
  margin-bottom: var(--space-5);
}

.step-card-btn {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  padding: var(--space-3);
  background: var(--bg-surface);
  border: 1.5px solid var(--border-strong);
  cursor: pointer;
  text-align: left;
  border-radius: var(--radius-xs);
  transition:
    transform var(--duration-fast) var(--ease-mech-out),
    border-color var(--duration-fast) var(--ease-mech-out),
    box-shadow var(--duration-fast) var(--ease-mech-out);
}

.step-card-btn:hover {
  transform: translate(-1px, -1px);
  box-shadow: var(--shadow-mech-sm);
}

.step-card-btn.active {
  border: 2px solid var(--signal-ochre);
  background: var(--signal-ochre-tint);
  box-shadow: var(--shadow-mech-sm);
}

.step-num {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--signal-ochre);
  margin-bottom: 0.2rem;
}

/* ==========================================================================
   14. AI GOVERNOR TELEMETRY DECK
   ========================================================================== */
.governor-telemetry-deck {
  background: var(--bg-plate);
  color: var(--text-on-plate);
  border-top: var(--border-width-strong) solid var(--border-strong);
  padding: var(--space-5);
  isolation: isolate;
}

.governor-deck-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-bottom: var(--space-4);
  border-bottom: 1px solid #333330;
  padding-bottom: var(--space-2);
}

.governor-deck-title {
  font-family: var(--font-mono);
  font-size: 0.76rem;
  font-weight: 700;
  letter-spacing: var(--tracking-wide);
  color: var(--signal-brass-bright);
}

.governor-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-4);
}

.governor-card {
  background: #1C1C1A;
  border: 1px solid #383834;
  padding: var(--space-3);
  border-radius: var(--radius-xs);
}

.governor-tag {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  font-weight: 700;
  color: var(--signal-cobalt);
  display: block;
  margin-bottom: var(--space-1);
  letter-spacing: var(--tracking-wide);
}

.governor-body {
  font-family: var(--font-mono);
  font-size: 0.76rem;
  line-height: var(--leading-normal);
  color: var(--text-on-plate);
}

.punch-card-receipt .governor-tag {
  color: var(--signal-brass-bright);
}

/* ==========================================================================
   15. SECTION SCAFFOLDING & CARDS
   ========================================================================== */
.section {
  padding: var(--space-16) 0;
  border-bottom: var(--border-width-strong) solid var(--border-strong);
  isolation: isolate;
}

.section-header {
  max-width: 840px;
  margin-bottom: var(--space-8);
}

.spec-reg-bar {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 700;
  color: var(--text-muted);
  border-bottom: 1.5px solid var(--border-subtle);
  padding-bottom: var(--space-1);
  margin-bottom: var(--space-3);
}

.section-header h2 {
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 2.8vw, 2.4rem);
  font-weight: 700;
  line-height: var(--leading-tight);
  letter-spacing: var(--tracking-tight);
  color: var(--text-primary);
  margin-bottom: var(--space-3);
}

.card-grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-6);
}

.card-grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-6);
}

.info-card {
  background: var(--bg-surface);
  border: 1.5px solid var(--border-strong);
  padding: var(--space-6);
  box-shadow: var(--shadow-mech);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  isolation: isolate;
}

.info-card.border-crimson { border-top: 4px solid var(--signal-vermilion); }
.info-card.border-amber { border-top: 4px solid var(--signal-ochre); }
.info-card.border-cyan { border-top: 4px solid var(--signal-cobalt); }
.info-card.border-emerald { border-top: 4px solid var(--signal-cobalt); }

.arch-diagram-frame {
  background: var(--bg-canvas);
  border: var(--border-width-strong) solid var(--border-strong);
  box-shadow: var(--shadow-mech);
  padding: var(--space-4);
  margin-bottom: var(--space-8);
  isolation: isolate;
}

.arch-diagram-frame img {
  width: 100%;
  height: auto;
  display: block;
}

/* ==========================================================================
   16. SUBSYSTEM TABS (7 Patented Subsystems)
   ========================================================================== */
.subsystem-layout {
  display: grid;
  grid-template-columns: 340px 1fr;
  gap: var(--space-6);
  align-items: start;
}

.subsystem-nav {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.subsystem-btn {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  padding: var(--space-3) var(--space-4);
  background: var(--bg-surface);
  border: 1.5px solid var(--border-strong);
  cursor: pointer;
  text-align: left;
  border-radius: var(--radius-xs);
  transition:
    transform var(--duration-fast) var(--ease-mech-out),
    background-color var(--duration-fast) var(--ease-mech-out),
    border-color var(--duration-fast) var(--ease-mech-out),
    box-shadow var(--duration-fast) var(--ease-mech-out);
}

.subsystem-btn:hover {
  transform: translate(-1px, -1px);
  box-shadow: var(--shadow-mech-sm);
}

.subsystem-btn.active {
  background: var(--bg-plate);
  color: var(--text-on-plate);
  border-color: var(--signal-brass-bright);
  box-shadow: var(--shadow-mech);
}

.subsystem-btn-title {
  font-family: var(--font-sans);
  font-size: 0.88rem;
  font-weight: 700;
  margin-bottom: 0.2rem;
  color: var(--text-primary);
}

.subsystem-btn.active .subsystem-btn-title {
  color: var(--text-on-plate);
}

.subsystem-btn-code {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  color: var(--text-muted);
}

.subsystem-btn.active .subsystem-btn-code {
  color: var(--signal-brass-bright);
}

.subsystem-detail-pane {
  display: none;
}

.subsystem-detail-pane.active {
  display: block;
}

/* ==========================================================================
   17. DATA TABLES & BADGES
   ========================================================================== */
.table-responsive {
  width: 100%;
  overflow-x: auto;
  border: var(--border-width-strong) solid var(--border-strong);
  box-shadow: var(--shadow-mech);
  background: var(--bg-surface);
  margin-bottom: var(--space-8);
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: var(--text-sm);
}

.data-table th {
  background: var(--bg-recessed);
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: var(--tracking-wide);
  padding: 0.85rem 1rem;
  border-bottom: var(--border-width-strong) solid var(--border-strong);
  border-right: 1px solid var(--border-subtle);
}

.data-table td {
  padding: 0.85rem 1rem;
  border-bottom: 1px solid var(--border-subtle);
  border-right: 1px solid var(--border-subtle);
  color: var(--text-secondary);
  vertical-align: top;
}

.data-table tr:last-child td {
  border-bottom: none;
}

.data-table th:last-child,
.data-table td:last-child {
  border-right: none;
}

.data-table th.highlight-col,
.data-table td.highlight-col {
  background: var(--signal-cobalt-tint);
  border-left: 2px solid var(--signal-cobalt);
  border-right: 2px solid var(--signal-cobalt);
  color: var(--text-primary);
}

.badge-pass {
  display: inline-flex;
  align-items: center;
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius-xs);
  font-family: var(--font-mono);
  font-size: 0.74rem;
  font-weight: 700;
  background: var(--signal-cobalt-tint);
  color: var(--signal-cobalt);
  border: 1.5px solid var(--signal-cobalt);
}

.badge-fail {
  display: inline-flex;
  align-items: center;
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius-xs);
  font-family: var(--font-mono);
  font-size: 0.74rem;
  font-weight: 700;
  background: var(--signal-vermilion-tint);
  color: var(--signal-vermilion);
  border: 1.5px solid var(--signal-vermilion);
}

.badge-warn {
  display: inline-flex;
  align-items: center;
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius-xs);
  font-family: var(--font-mono);
  font-size: 0.74rem;
  font-weight: 700;
  background: var(--signal-ochre-tint);
  color: var(--signal-ochre);
  border: 1.5px solid var(--signal-ochre);
}

/* ==========================================================================
   18. PRICING CARDS
   ========================================================================== */
.pricing-card {
  background: var(--bg-surface);
  border: var(--border-width-strong) solid var(--border-strong);
  padding: var(--space-8);
  box-shadow: var(--shadow-mech);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: var(--space-6);
  position: relative;
  isolation: isolate;
}

.pricing-card.featured {
  border: 2.5px solid var(--signal-vermilion);
  box-shadow: var(--shadow-mech-lg);
}

.pricing-tier-badge {
  position: absolute;
  top: -12px;
  right: 16px;
  background: var(--signal-vermilion);
  color: #FAF7F2;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: var(--tracking-wide);
  padding: 0.25rem 0.65rem;
  border: 1.5px solid var(--border-strong);
}

.price-figure {
  font-family: var(--font-display);
  font-size: 2.6rem;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.1;
  margin: var(--space-2) 0 var(--space-1);
}

.price-period {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-bottom: var(--space-4);
}

.feature-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
}

.feature-list li {
  display: flex;
  align-items: flex-start;
  gap: 0.65rem;
  font-size: var(--text-sm);
  color: var(--text-secondary);
}

.feature-check {
  color: var(--signal-cobalt);
  font-weight: 700;
  flex-shrink: 0;
}

/* ==========================================================================
   19. FAQ ACCORDION & TELEMETRY PANEL
   ========================================================================== */
.faq-list {
  max-width: 920px;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.faq-item {
  background: var(--bg-surface);
  border: 1.5px solid var(--border-strong);
  box-shadow: var(--shadow-mech-sm);
  border-radius: var(--radius-xs);
  overflow: hidden;
}

.faq-item summary {
  padding: 1rem 1.25rem;
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
  cursor: pointer;
  background: var(--bg-surface);
  transition: background-color var(--duration-fast) var(--ease-mech-out);
}

.faq-item summary:hover {
  background: var(--bg-recessed);
}

.faq-item summary:focus-visible {
  outline: 2px solid var(--signal-cobalt);
  outline-offset: -2px;
}

.faq-body {
  padding: 1rem 1.25rem;
  border-top: 1px solid var(--border-subtle);
  font-size: 0.92rem;
  line-height: var(--leading-relaxed);
  color: var(--text-secondary);
}

.telemetry-panel {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-4);
  background: var(--bg-recessed);
  border: 1.5px solid var(--border-strong);
  padding: 1rem 1.25rem;
  margin-top: var(--space-8);
  font-size: var(--text-sm);
}

.patent-statutory-box {
  background: var(--bg-recessed);
  border: 1.5px solid var(--border-strong);
  padding: 1.25rem;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  line-height: var(--leading-relaxed);
  color: var(--text-secondary);
  margin-top: var(--space-8);
}

/* ==========================================================================
   20. SITE FOOTER
   ========================================================================== */
.site-footer {
  background: var(--bg-plate);
  color: var(--text-on-plate);
  border-top: var(--border-width-strong) solid var(--border-strong);
  padding: var(--space-12) 0 var(--space-8);
  isolation: isolate;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1fr;
  gap: var(--space-8);
  margin-bottom: var(--space-8);
}

.footer-col h4 {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: var(--tracking-wide);
  color: var(--signal-brass-bright);
  margin-bottom: var(--space-4);
}

.footer-links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.footer-links a {
  color: var(--text-muted-on-plate);
  font-size: 0.85rem;
  text-decoration: none;
  transition: color var(--duration-fast) var(--ease-mech-out);
}

.footer-links a:hover {
  color: var(--text-on-plate);
}

/* Utility Colours */
.cobalt { color: var(--signal-cobalt); }
.cyan { color: var(--signal-cobalt); }
.amber { color: var(--signal-ochre); }
.crimson, .red { color: var(--signal-vermilion); }
.green { color: #15803D; }

/* ==========================================================================
   21. RESPONSIVE BREAKPOINTS (Craft R8, R12)
   ========================================================================== */
@media (max-width: 1024px) {
  .hero-grid,
  .dual-fork-strip,
  .sim-workspace-grid,
  .subsystem-layout,
  .card-grid-2 {
    grid-template-columns: 1fr;
  }

  .lever-rack-grid,
  .metrics-strip,
  .governor-grid,
  .card-grid-3 {
    grid-template-columns: repeat(2, 1fr);
  }

  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .nav-bar {
    height: auto;
    flex-wrap: wrap;
    padding: var(--space-3) 0;
  }

  .nav-links {
    flex-wrap: wrap;
    gap: var(--space-3);
  }

  .lever-rack-grid,
  .metrics-strip,
  .stepper-grid,
  .governor-grid,
  .card-grid-3,
  .footer-grid {
    grid-template-columns: 1fr;
  }

  .top-signal-inner {
    flex-direction: column;
    align-items: flex-start;
  }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  .btn, .lever-unit, .step-card-btn, .subsystem-btn {
    transition: none !important;
  }
}