/* ===================================================================
   SPLogbook — Lab-Grade System Architecture Stylesheet
   High-Density Systems Interface • Zero-Slop • Zero GC Runtime Aesthetics
   WCAG 2.2 AA / AAA Compliant • High-DPI Calibrated
   =================================================================== */

@import url('https://fonts.googleapis.com/css2?family=JetBrains+Mono:wght@400;500;600;700;800&family=Space+Grotesk:wght@500;700;800&family=Inter:wght@400;500;600;700&display=swap');

:root {
  /* Chassis & Enclosure (Machined Aluminum & Powder-Coated Metal) */
  --chassis-bg: #090B0E;
  --rack-faceplate: #11151C;
  --card-surface: #181E28;
  --card-surface-hover: #222B38;
  --border-machine: #283342;
  --border-subtle: #1C2430;
  --border-active: #485973;

  /* Instruments & RF Signal Indicators (High Luminance Contrast) */
  --nixie-amber: #FF9900;
  --nixie-amber-dim: rgba(255, 153, 0, 0.14);
  --phosphor-green: #10E778;
  --phosphor-green-dim: rgba(16, 231, 120, 0.14);
  --overload-red: #FF334B;
  --overload-red-dim: rgba(255, 51, 75, 0.14);
  --rf-cyan: #00D5FF;
  --rf-cyan-dim: rgba(0, 213, 255, 0.14);

  /* Typography (WCAG 2.2 AAA / AA Validated) */
  --text-primary: #F0F4F8;     /* Contrast 14.8:1 on rack-faceplate */
  --text-secondary: #B8C4D2;   /* Contrast 8.9:1 on rack-faceplate */
  --text-muted: #8595A8;       /* Contrast 5.2:1 on rack-faceplate (AA verified) */

  /* Typography Stacks */
  --font-mono: "JetBrains Mono", Consolas, "Courier New", monospace;
  --font-display: "Space Grotesk", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;

  /* Dimensions & Mechanical Tolerances */
  --radius-0: 0px;
  --radius-btn: 2px;
  --container-max: 1320px;
  --header-ribbon-h: 28px;
  --header-deck-h: 52px;
  --header-h: 80px;
  --trans-fast: 0.15s ease-out;
}

[data-theme="light"] {
  /* High-Contrast Laboratory Bench Mode (Calibrated WCAG AAA/AA) */
  --chassis-bg: #EAEFF5;
  --rack-faceplate: #F4F7FA;
  --card-surface: #FFFFFF;
  --card-surface-hover: #F0F4F8;
  --border-machine: #CBD5E1;
  --border-subtle: #DFE5EC;
  --border-active: #94A3B8;

  --nixie-amber: #B45309;      /* Dark amber ensuring 5.1:1 contrast on light backgrounds */
  --nixie-amber-dim: rgba(180, 83, 9, 0.12);
  --phosphor-green: #047857;   /* Contrast 5.4:1 */
  --phosphor-green-dim: rgba(4, 120, 87, 0.12);
  --overload-red: #B91C1C;
  --overload-red-dim: rgba(185, 28, 28, 0.12);
  --rf-cyan: #0369A1;
  --rf-cyan-dim: rgba(3, 105, 161, 0.12);

  --text-primary: #0F172A;     /* Contrast 14.2:1 on rack-faceplate */
  --text-secondary: #334155;   /* Contrast 9.1:1 on rack-faceplate */
  --text-muted: #475569;       /* Contrast 5.4:1 on rack-faceplate */
}

/* ===================================================================
   Base Reset & Industrial Geometry
   =================================================================== */

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  border-radius: var(--radius-0);
}

html {
  scroll-behavior: smooth;
  font-size: 14px;
  background-color: var(--chassis-bg);
  color: var(--text-primary);
}

body {
  font-family: var(--font-sans);
  background-color: var(--chassis-bg);
  color: var(--text-primary);
  line-height: 1.55;
  min-height: 100vh;
  padding-top: var(--header-h);
  overflow-x: hidden;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

/* Anchor Target Scroll Offset Compensation */
section, [id] {
  scroll-margin-top: calc(var(--header-h) + 16px);
}

/* Accessibility Focus States (WCAG 2.4.7) */
:focus-visible {
  outline: 2px solid var(--nixie-amber) !important;
  outline-offset: 2px !important;
}

/* Tabular Monospace Numerals */
.tabular-nums, code, pre, .mono-data, .freq-readout {
  font-family: var(--font-mono);
  font-feature-settings: "tnum" 1, "zero" 1;
  font-variant-numeric: tabular-nums;
}

.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 1.25rem;
}

a {
  color: var(--rf-cyan);
  text-decoration: none;
  transition: color var(--trans-fast);
}

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

/* ===================================================================
   01. TWO-TIER LABORATORY COCKPIT HEADER (Station Telemetry + Main Deck)
   =================================================================== */

.cockpit-bar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--header-h);
  z-index: 1000;
  display: flex;
  flex-direction: column;
}

/* Tier 1: Real-Time Laboratory Telemetry Strip (28px) */
.cockpit-telemetry-ribbon {
  height: var(--header-ribbon-h);
  background-color: #070a0e;
  border-bottom: 1px solid var(--border-machine);
  display: flex;
  align-items: center;
  width: 100%;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  overflow: hidden;
  user-select: none;
}

[data-theme="light"] .cockpit-telemetry-ribbon {
  background-color: #0c121c; /* High-contrast OLED console strip */
  border-bottom-color: #1e293b;
}

.ribbon-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 1.25rem;
  white-space: nowrap;
}

.telemetry-cluster {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  white-space: nowrap;
}

.telem-unit {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  white-space: nowrap;
  flex-shrink: 0;
}

.telem-lbl {
  color: #64748b;
  text-transform: uppercase;
  font-weight: 500;
  letter-spacing: 0.04em;
  white-space: nowrap;
}

[data-theme="light"] .telem-lbl {
  color: #94a3b8;
}

.telem-val {
  font-weight: 600;
  color: #f1f5f9;
  letter-spacing: 0.02em;
  white-space: nowrap;
}

.telem-val.green { color: #10b981; }
.telem-val.amber { color: #f59e0b; }
.telem-val.cyan  { color: #38bdf8; }

.telem-loc {
  font-size: 0.65rem;
  color: #94a3b8;
  padding: 0 4px;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.12);
  margin-left: 2px;
}

.telem-sep {
  color: #263345;
  font-size: 0.7rem;
  user-select: none;
}

[data-theme="light"] .telem-sep {
  color: #334155;
}

.led-indicator {
  display: inline-block;
  width: 6px;
  height: 6px;
  background-color: var(--text-muted);
}

.led-green {
  background-color: #10b981;
  box-shadow: 0 0 6px #10b981;
}

.led-amber {
  background-color: #f59e0b;
  box-shadow: 0 0 6px #f59e0b;
}

/* Tier 2: Main Cockpit Navigation Deck (52px) */
.cockpit-main-deck {
  height: var(--header-deck-h);
  background-color: var(--rack-faceplate);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-machine);
  display: flex;
  align-items: center;
  width: 100%;
}

.deck-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 1.25rem;
  gap: 1.5rem;
}

.brand-group {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--text-primary);
  flex-shrink: 0;
}

.brand-icon {
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #000;
  border: 1px solid var(--border-machine);
  flex-shrink: 0;
}

.brand-title {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-primary);
  white-space: nowrap;
}

.brand-tag {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  padding: 2px 6px;
  background: var(--nixie-amber-dim);
  border: 1px solid var(--nixie-amber);
  color: var(--nixie-amber);
  font-weight: 700;
  letter-spacing: 0.06em;
  white-space: nowrap;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.nav-item {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--text-secondary);
  padding: 0.42rem 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  border: 1px solid transparent;
  border-radius: var(--radius-btn);
  transition: all var(--trans-fast);
  white-space: nowrap;
  text-decoration: none;
}

.nav-item:hover {
  color: var(--text-primary);
  background-color: var(--card-surface);
  border-color: var(--border-machine);
}

.cockpit-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-shrink: 0;
}

.btn-cta-nav {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  background: var(--nixie-amber-dim);
  border: 1px solid var(--nixie-amber);
  color: var(--nixie-amber);
  font-family: var(--font-mono);
  font-size: 0.76rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 0 0.85rem;
  height: 32px;
  line-height: 32px;
  border-radius: var(--radius-btn);
  text-decoration: none;
  transition: all var(--trans-fast);
  white-space: nowrap;
}

.btn-cta-nav:hover {
  background: var(--nixie-amber);
  color: #000;
  box-shadow: 0 0 10px rgba(245, 158, 11, 0.4);
}

.btn-ctrl {
  background: var(--card-surface);
  border: 1px solid var(--border-machine);
  color: var(--text-secondary);
  height: 32px;
  padding: 0 0.65rem;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  cursor: pointer;
  border-radius: var(--radius-btn);
  transition: all var(--trans-fast);
  white-space: nowrap;
}

.btn-ctrl:hover {
  background: var(--card-surface-hover);
  border-color: var(--border-active);
  color: var(--text-primary);
}

/* Language Selector */
.lang-wrapper {
  position: relative;
}

.lang-menu {
  display: none;
  position: absolute;
  top: 100%;
  right: 0;
  margin-top: 4px;
  background: var(--rack-faceplate);
  border: 1px solid var(--border-machine);
  width: 140px;
  z-index: 1100;
  box-shadow: 0 6px 16px rgba(0, 0, 0, 0.4);
}

.lang-menu.active {
  display: block;
}

.lang-option {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: 0.45rem 0.65rem;
  background: transparent;
  border: none;
  color: var(--text-secondary);
  font-family: var(--font-mono);
  font-size: 0.74rem;
  cursor: pointer;
  text-align: left;
}

.lang-option:hover, .lang-option.selected {
  background: var(--card-surface);
  color: var(--nixie-amber);
}

.mobile-toggle {
  display: none;
}

/* ===================================================================
   02. HERO SECTION — DUAL-CHANNEL LABORATORY HUD
   =================================================================== */

.hero-rack {
  padding: 2.75rem 0;
  border-bottom: 1px solid var(--border-machine);
  background: var(--chassis-bg);
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 1.75rem;
  align-items: stretch;
}

.channel-card {
  background: var(--rack-faceplate);
  border: 1px solid var(--border-machine);
  display: flex;
  flex-direction: column;
}

.channel-hdr {
  height: 32px;
  background: #0B0E14;
  border-bottom: 1px solid var(--border-machine);
  padding: 0 0.85rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-muted);
  letter-spacing: 0.04em;
}

.channel-body {
  padding: 1.75rem 1.5rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  flex-grow: 1;
}

.hero-headline {
  font-family: var(--font-display);
  font-size: 2.25rem;
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.02em;
  text-transform: uppercase;
  margin-bottom: 1.15rem;
  color: var(--text-primary);
}

.hero-headline .accent-amber {
  color: var(--nixie-amber);
}

.hero-abstract {
  font-size: 1rem;
  color: var(--text-secondary);
  line-height: 1.6;
  max-width: 620px;
  margin-bottom: 1.6rem;
}

.hero-abstract code {
  font-family: var(--font-mono);
  background: var(--card-surface);
  border: 1px solid var(--border-machine);
  padding: 1px 4px;
  color: var(--rf-cyan);
}

/* Key Metrics Strip */
.metrics-quad {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1px;
  background: var(--border-machine);
  border: 1px solid var(--border-machine);
  margin-bottom: 1.6rem;
}

.metric-cell {
  background: var(--card-surface);
  padding: 0.75rem 0.65rem;
}

.metric-val {
  display: block;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.2rem;
}

.metric-val.green { color: var(--phosphor-green); }
.metric-val.amber { color: var(--nixie-amber); }
.metric-val.cyan { color: var(--rf-cyan); }

.metric-lbl {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.03em;
  line-height: 1.3;
}

/* Dual Engine CTA Block */
.cta-dock {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.cta-btns {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.btn-action-primary {
  background: var(--nixie-amber);
  color: #000;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  padding: 0.75rem 1.35rem;
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  border: 1px solid var(--nixie-amber);
  border-radius: var(--radius-btn);
  cursor: pointer;
  transition: all var(--trans-fast);
}

.btn-action-primary:hover {
  background: #FFB338;
  box-shadow: 0 0 14px rgba(255, 153, 0, 0.4);
}

.btn-action-secondary {
  background: var(--card-surface);
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 600;
  padding: 0.75rem 1.25rem;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  border: 1px solid var(--border-machine);
  border-radius: var(--radius-btn);
  cursor: pointer;
  transition: all var(--trans-fast);
}

.btn-action-secondary:hover {
  background: var(--card-surface-hover);
  border-color: var(--rf-cyan);
  color: var(--rf-cyan);
}

/* Real Cargo Terminal Snippet */
.term-strip {
  background: #050709;
  border: 1px solid var(--border-machine);
  padding: 0.6rem 0.85rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-family: var(--font-mono);
  font-size: 0.78rem;
}

.term-cmd-wrap {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  overflow-x: auto;
}

.term-prompt {
  color: var(--text-muted);
  user-select: none;
}

.term-text {
  color: var(--phosphor-green);
  user-select: all;
  white-space: nowrap;
}

.btn-term-copy {
  background: var(--card-surface);
  border: 1px solid var(--border-machine);
  color: var(--text-secondary);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  padding: 3px 8px;
  cursor: pointer;
  border-radius: var(--radius-btn);
  flex-shrink: 0;
}

.btn-term-copy:hover {
  color: var(--nixie-amber);
  border-color: var(--nixie-amber);
}

/* ===================================================================
   RIGHT CHANNEL: LABORATORY DSP VFO RACKMOUNT
   =================================================================== */

.instrument-bay {
  padding: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.vfo-chassis {
  background: #06080B;
  border: 1px solid var(--border-subtle);
  padding: 0.85rem;
}

.vfo-topline {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.35rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-muted);
}

.vfo-digits-wrap {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
}

.vfo-digits {
  font-family: var(--font-mono);
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--nixie-amber);
  letter-spacing: 0.04em;
  text-shadow: 0 0 10px rgba(255, 153, 0, 0.25);
}

.vfo-unit {
  font-size: 0.9rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

.vfo-controls {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  margin-top: 0.65rem;
  padding-top: 0.5rem;
  border-top: 1px solid var(--border-subtle);
  flex-wrap: wrap;
}

.vfo-steps, .vfo-modes {
  display: flex;
  gap: 0.25rem;
}

.btn-vfo-key {
  background: var(--card-surface);
  border: 1px solid var(--border-machine);
  color: var(--text-secondary);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  padding: 3px 7px;
  cursor: pointer;
  border-radius: var(--radius-btn);
  transition: all var(--trans-fast);
}

.btn-vfo-key:hover {
  background: var(--card-surface-hover);
  color: var(--nixie-amber);
  border-color: var(--nixie-amber);
}

.btn-vfo-key.active {
  background: var(--nixie-amber-dim);
  color: var(--nixie-amber);
  border-color: var(--nixie-amber);
  font-weight: 700;
}

/* S-Meter Precision Gauge */
.smeter-chassis {
  background: #06080B;
  border: 1px solid var(--border-subtle);
  padding: 0.45rem 0.75rem;
}

.smeter-scale-strip {
  display: flex;
  justify-content: space-between;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  color: var(--text-muted);
  margin-bottom: 3px;
}

.smeter-rail {
  height: 8px;
  background: #141A24;
  border: 1px solid var(--border-machine);
  display: flex;
}

.smeter-fill-active {
  background: var(--phosphor-green);
  transition: width 0.15s ease-out;
}

.smeter-fill-overload {
  background: var(--overload-red);
  transition: width 0.15s ease-out;
}

/* Audio FFT Spectrum Waterfall */
.waterfall-chassis {
  background: #030508;
  border: 1px solid var(--border-subtle);
  padding: 0.4rem;
}

.waterfall-topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  color: var(--text-muted);
  margin-bottom: 3px;
  text-transform: uppercase;
}

.waterfall-canvas {
  width: 100%;
  height: 60px;
  display: block;
  background: #020406;
  border: 1px solid #0F151F;
}

/* Native Screenshot Preview */
.screenshot-chassis {
  position: relative;
  border: 1px solid var(--border-machine);
  background: #000;
  cursor: pointer;
  padding: 0;
  display: block;
  width: 100%;
}

.screenshot-chassis img {
  width: 100%;
  height: auto;
  display: block;
  opacity: 0.92;
  transition: opacity var(--trans-fast);
}

.screenshot-chassis:hover img {
  opacity: 1;
}

.screenshot-zoom-badge {
  position: absolute;
  bottom: 8px;
  right: 8px;
  background: rgba(9, 11, 14, 0.92);
  border: 1px solid var(--border-machine);
  color: var(--text-secondary);
  font-family: var(--font-mono);
  font-size: 0.68rem;
  padding: 3px 8px;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

/* ===================================================================
   03. STATION TOPOLOGY & SERIAL CAT MULTIPLEXER
   =================================================================== */

.section-rack {
  padding: 4.5rem 0;
  position: relative;
}

.section-rack.alt-bg {
  background: var(--rack-faceplate);
  border-top: 1px solid var(--border-machine);
  border-bottom: 1px solid var(--border-machine);
}

.section-heading-block {
  margin-bottom: 2.75rem;
}

.section-kicker {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  color: var(--nixie-amber);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  display: inline-block;
  margin-bottom: 0.4rem;
}

.section-title {
  font-family: var(--font-display);
  font-size: 1.85rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: -0.01em;
  color: var(--text-primary);
  margin-bottom: 0.65rem;
}

.section-desc {
  color: var(--text-secondary);
  font-size: 1rem;
  max-width: 760px;
  line-height: 1.6;
}

/* Schematic Network Box */
.schematic-box {
  background: #07090D;
  border: 1px solid var(--border-machine);
  padding: 1.75rem;
  margin-bottom: 2rem;
}

.topology-columns {
  display: grid;
  grid-template-columns: 1fr 1.25fr 1fr;
  gap: 1.5rem;
  align-items: stretch;
}

.topo-card {
  background: var(--rack-faceplate);
  border: 1px solid var(--border-machine);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.topo-card.hub-active {
  border-color: var(--nixie-amber);
  background: #141924;
}

.topo-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--border-subtle);
  padding-bottom: 0.5rem;
}

.topo-card-title {
  font-family: var(--font-mono);
  font-size: 0.84rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--text-primary);
}

.topo-port-badge {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  padding: 2px 6px;
  background: #0A0D12;
  border: 1px solid var(--border-machine);
  color: var(--phosphor-green);
}

.topo-card-text {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.55;
  flex-grow: 1;
}

.topo-specs-list {
  list-style: none;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  margin-top: 0.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.topo-specs-list li {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 3px 6px;
  background: #0B0E14;
}

.topo-specs-list li span:first-child {
  color: var(--text-muted);
}

.topo-specs-list li span:last-child {
  color: var(--text-primary);
  font-weight: 600;
}

/* Feature Columns */
.trio-cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
}

.feature-box {
  background: var(--rack-faceplate);
  border: 1px solid var(--border-machine);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: border-color var(--trans-fast);
}

.feature-box:hover {
  border-color: var(--border-active);
}

.feature-seq {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1rem;
}

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

.feature-svg-icon {
  width: 26px;
  height: 26px;
  stroke: var(--nixie-amber);
  fill: none;
  stroke-width: 1.8;
}

.feature-h3 {
  font-family: var(--font-display);
  font-size: 1.15rem;
  font-weight: 700;
  text-transform: uppercase;
  margin-bottom: 0.65rem;
  color: var(--text-primary);
}

.feature-p {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 1.25rem;
  flex-grow: 1;
}

.feature-bullets {
  list-style: none;
  border-top: 1px solid var(--border-subtle);
  padding-top: 0.75rem;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  color: var(--text-muted);
}

.feature-bullets li span {
  color: var(--text-primary);
}

/* ===================================================================
   04. INTERACTIVE QSO LAB & IONOSPHERE (Great-Circle & VOACAP)
   =================================================================== */

.qsolab-box {
  background: #07090D;
  border: 1px solid var(--border-machine);
  padding: 1.5rem;
}

.qsolab-inputs {
  display: grid;
  grid-template-columns: 1.2fr 1fr auto;
  gap: 1rem;
  margin-bottom: 1.25rem;
  background: var(--rack-faceplate);
  border: 1px solid var(--border-machine);
  padding: 1.15rem;
}

.input-block {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.input-label {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  text-transform: uppercase;
  color: var(--text-muted);
}

.qsolab-field {
  background: #06080B;
  border: 1px solid var(--border-machine);
  color: var(--nixie-amber);
  font-family: var(--font-mono);
  font-size: 1.15rem;
  font-weight: 700;
  padding: 0.55rem 0.75rem;
  text-transform: uppercase;
  border-radius: var(--radius-btn);
}

.qsolab-field:focus {
  outline: none;
  border-color: var(--nixie-amber);
  box-shadow: 0 0 8px rgba(255, 153, 0, 0.3);
}

.presets-rack {
  display: flex;
  align-items: flex-end;
  gap: 0.4rem;
  flex-wrap: wrap;
}

.btn-preset {
  background: var(--card-surface);
  border: 1px solid var(--border-machine);
  color: var(--text-secondary);
  font-family: var(--font-mono);
  font-size: 0.74rem;
  padding: 0.6rem 0.75rem;
  cursor: pointer;
  border-radius: var(--radius-btn);
  transition: all var(--trans-fast);
}

.btn-preset:hover {
  background: var(--card-surface-hover);
  color: var(--rf-cyan);
  border-color: var(--rf-cyan);
}

/* Radar & Output Grid */
.telemetry-results-row {
  display: grid;
  grid-template-columns: 140px 1fr;
  gap: 1.25rem;
  align-items: center;
  margin-bottom: 1.25rem;
  background: var(--rack-faceplate);
  border: 1px solid var(--border-machine);
  padding: 1.15rem;
}

.radar-bay {
  width: 120px;
  height: 120px;
  margin: 0 auto;
}

#compassCanvas {
  width: 120px;
  height: 120px;
  display: block;
}

.outputs-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.75rem;
}

.output-card {
  background: #0B0E14;
  border: 1px solid var(--border-machine);
  padding: 0.75rem;
}

.output-card-lbl {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  color: var(--text-muted);
  text-transform: uppercase;
}

.output-card-val {
  font-family: var(--font-mono);
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-top: 0.25rem;
}

/* VOACAP Matrix */
.voacap-matrix {
  background: var(--rack-faceplate);
  border: 1px solid var(--border-machine);
  padding: 1.15rem;
}

.matrix-topline {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
}

.bands-matrix-cells {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 0.5rem;
}

.band-cell {
  background: #090B0E;
  border: 1px solid var(--border-machine);
  padding: 0.65rem 0.5rem;
  text-align: center;
}

.band-lbl {
  font-family: var(--font-mono);
  font-size: 0.76rem;
  color: var(--text-muted);
  font-weight: 700;
}

.band-state {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  margin-top: 0.25rem;
  font-weight: 600;
}

.band-state.open { color: var(--phosphor-green); }
.band-state.good { color: var(--rf-cyan); }
.band-state.marginal { color: var(--nixie-amber); }
.band-state.closed { color: var(--text-muted); }

/* Rotator Simulation Bar */
.rotator-bar {
  margin-top: 1rem;
  background: #0B0E14;
  border: 1px solid var(--border-machine);
  padding: 0.75rem 1rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.btn-exec-rotator {
  background: var(--card-surface);
  border: 1px solid var(--border-machine);
  color: var(--phosphor-green);
  font-family: var(--font-mono);
  font-size: 0.74rem;
  font-weight: 600;
  padding: 0.45rem 0.85rem;
  cursor: pointer;
  border-radius: var(--radius-btn);
  transition: all var(--trans-fast);
}

.btn-exec-rotator:hover {
  background: var(--phosphor-green);
  color: #000;
}

/* ===================================================================
   05. SYSTEM BENCHMARKS TABLE (Full A11y & Scoped Headers)
   =================================================================== */

.bench-container {
  background: var(--rack-faceplate);
  border: 1px solid var(--border-machine);
  overflow-x: auto;
}

.bench-grid-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.86rem;
  text-align: left;
}

.bench-grid-table th, .bench-grid-table td {
  padding: 0.9rem 1.15rem;
  border-bottom: 1px solid var(--border-subtle);
  border-right: 1px solid var(--border-subtle);
}

.bench-grid-table th {
  background: #080B10;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  color: var(--text-muted);
  letter-spacing: 0.05em;
}

.bench-grid-table th.col-splogbook-hdr {
  background: #111824;
  color: var(--nixie-amber);
  border-bottom: 2px solid var(--nixie-amber);
}

.bench-grid-table td.col-splogbook-data {
  background: rgba(255, 153, 0, 0.03);
  font-weight: 700;
  color: var(--phosphor-green);
  font-family: var(--font-mono);
}

.bench-grid-table th[scope="row"] {
  background: transparent;
  color: var(--text-primary);
  font-weight: 600;
  font-family: var(--font-sans);
  text-transform: none;
}

.bench-grid-table tr:hover td, .bench-grid-table tr:hover th[scope="row"] {
  background-color: var(--card-surface-hover);
}

/* ===================================================================
   06. CRYPTOGRAPHIC DISTRIBUTION MATRIX & CARDS
   =================================================================== */

.distro-wrapper {
  background: var(--rack-faceplate);
  border: 1px solid var(--border-machine);
  margin-bottom: 1.5rem;
}

.distro-row-item {
  display: grid;
  grid-template-columns: 1.2fr 1.6fr 0.8fr 1.8fr 1fr;
  align-items: center;
  padding: 0.9rem 1.25rem;
  border-bottom: 1px solid var(--border-subtle);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  gap: 0.75rem;
}

.distro-row-item.distro-hdr {
  background: #090C11;
  font-size: 0.72rem;
  text-transform: uppercase;
  color: var(--text-muted);
  font-weight: 700;
}

.distro-row-item:last-child {
  border-bottom: none;
}

.distro-platform-cell {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 600;
  color: var(--text-primary);
}

.distro-hash-cell {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.72rem;
}

.hash-token {
  user-select: all;
  color: var(--text-secondary);
}

.btn-distro-get {
  background: var(--card-surface);
  border: 1px solid var(--border-machine);
  color: var(--text-primary);
  padding: 0.45rem 0.75rem;
  text-align: center;
  cursor: pointer;
  border-radius: var(--radius-btn);
  font-size: 0.76rem;
  font-weight: 600;
  transition: all var(--trans-fast);
}

.btn-distro-get:hover {
  background: var(--nixie-amber);
  color: #000;
  border-color: var(--nixie-amber);
}

.btn-distro-get.detected-os {
  background: var(--nixie-amber);
  color: #000;
  font-weight: 700;
  border-color: var(--nixie-amber);
}

/* ===================================================================
   07. HARDWARE TESTBENCH & RIG FUND
   =================================================================== */

.fund-box {
  background: #07090D;
  border: 1px solid var(--border-machine);
  padding: 2rem;
}



.fund-actions-columns {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.25rem;
}

.fund-action-card {
  background: var(--rack-faceplate);
  border: 1px solid var(--border-machine);
  padding: 1.35rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.fund-card-h3 {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--text-primary);
  margin-bottom: 0.4rem;
}

.fund-card-p {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.55;
  margin-bottom: 1.15rem;
  flex-grow: 1;
}

/* ===================================================================
   08. CONTACT & COMMUNITY
   =================================================================== */

.contact-channels {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
}

.contact-card {
  background: var(--rack-faceplate);
  border: 1px solid var(--border-machine);
  padding: 1.35rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.contact-type-tag {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  color: var(--phosphor-green);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.35rem;
}

.contact-title {
  font-family: var(--font-mono);
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.4rem;
}

.contact-desc {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.5;
  margin-bottom: 1rem;
  flex-grow: 1;
}

.contact-btn-row {
  display: flex;
  gap: 0.5rem;
}

/* ===================================================================
   09. FOOTER
   =================================================================== */

.site-footer {
  background: #050709;
  border-top: 1px solid var(--border-machine);
  padding: 3rem 0 2rem 0;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.footer-nav-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr;
  gap: 2rem;
  margin-bottom: 2rem;
}

.footer-col-hdr {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  text-transform: uppercase;
  color: var(--text-primary);
  letter-spacing: 0.05em;
  margin-bottom: 0.85rem;
}

.footer-links-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  font-family: var(--font-mono);
  font-size: 0.78rem;
}

.footer-links-list a {
  color: var(--text-secondary);
}

.footer-links-list a:hover {
  color: var(--nixie-amber);
}

.footer-subline {
  border-top: 1px solid var(--border-subtle);
  padding-top: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  flex-wrap: wrap;
  gap: 0.5rem;
}

/* ===================================================================
   10. LIGHTBOX DIALOG MODAL (Fully Accessible Native Dialog Pattern)
   =================================================================== */

.accessible-dialog {
  position: fixed;
  inset: 0;
  background: rgba(5, 7, 9, 0.94);
  z-index: 2000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1.5rem;
}

.accessible-dialog[hidden] {
  display: none;
}

.dialog-inner-frame {
  max-width: 1350px;
  width: 100%;
  background: var(--rack-faceplate);
  border: 1px solid var(--border-machine);
  padding: 0.5rem;
  position: relative;
}

.dialog-inner-frame img {
  width: 100%;
  height: auto;
  display: block;
}

.btn-dialog-close {
  position: absolute;
  top: 10px;
  right: 10px;
  background: #000;
  border: 1px solid var(--border-machine);
  color: var(--text-primary);
  width: 32px;
  height: 32px;
  cursor: pointer;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* ===================================================================
   KNOWLEDGE BASE & FAQ ACCORDION RACK (Lab-Grade UI)
   =================================================================== */

.faq-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  max-width: 980px;
  margin: 0 auto;
}

.faq-item {
  background: var(--rack-faceplate);
  border: 1px solid var(--border-machine);
  transition: border-color var(--trans-fast), background var(--trans-fast);
}

.faq-item[open] {
  border-color: var(--nixie-amber);
  background: var(--card-surface);
}

.faq-summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.1rem 1.25rem;
  cursor: pointer;
  user-select: none;
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
  list-style: none;
  transition: color var(--trans-fast);
}

.faq-summary::-webkit-details-marker {
  display: none;
}

.faq-summary:hover {
  color: var(--nixie-amber);
}

.faq-q-wrap {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  flex: 1;
}

.faq-q-badge {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 600;
  color: var(--phosphor-green);
  background: rgba(16, 231, 120, 0.08);
  border: 1px solid rgba(16, 231, 120, 0.25);
  padding: 2px 7px;
  flex-shrink: 0;
  letter-spacing: 0.04em;
}

.faq-item[open] .faq-q-badge {
  color: var(--nixie-amber);
  background: var(--nixie-amber-dim);
  border-color: rgba(255, 153, 0, 0.4);
}

.faq-q-text {
  line-height: 1.4;
}

.faq-icon-indicator {
  font-family: var(--font-mono);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-muted);
  flex-shrink: 0;
  margin-left: 1rem;
  display: inline-block;
  line-height: 1;
  transition: transform var(--trans-fast), color var(--trans-fast);
}

.faq-item[open] .faq-icon-indicator {
  transform: rotate(45deg);
  color: var(--nixie-amber);
}

.faq-answer {
  padding: 1.15rem 1.25rem 1.35rem;
  border-top: 1px solid var(--border-subtle);
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.65;
  background: rgba(0, 0, 0, 0.15);
}

[data-theme="light"] .faq-answer {
  background: rgba(0, 0, 0, 0.02);
}

.faq-answer strong {
  color: var(--text-primary);
}

.faq-answer code {
  font-family: var(--font-mono);
  font-size: 0.85em;
  background: var(--chassis-bg);
  border: 1px solid var(--border-machine);
  padding: 1px 5px;
  color: var(--rf-cyan);
}

/* ===================================================================
   RESPONSIVE DESIGN & BREAKPOINT ARCHITECTURE
   =================================================================== */

@media (max-width: 1200px) {
  .hide-on-laptop {
    display: none !important;
  }
}

@media (max-width: 1024px) {
  .nav-links {
    display: none;
    position: absolute;
    top: var(--header-h);
    left: 0;
    width: 100%;
    background: var(--rack-faceplate);
    border-bottom: 1px solid var(--border-machine);
    flex-direction: column;
    padding: 1rem 1.25rem;
    gap: 0.5rem;
    box-shadow: 0 12px 24px rgba(0, 0, 0, 0.5);
    z-index: 999;
  }
  .nav-links.active {
    display: flex;
  }
  .mobile-toggle {
    display: inline-flex;
  }
  .nav-item {
    width: 100%;
    padding: 0.65rem 0.85rem;
  }
  .hero-grid {
    grid-template-columns: 1fr;
  }
  .topology-columns {
    grid-template-columns: 1fr;
  }
  .trio-cards {
    grid-template-columns: 1fr;
  }
  .telemetry-results-row {
    grid-template-columns: 1fr;
  }
  .distro-row-item {
    grid-template-columns: 1fr 1fr;
    gap: 0.5rem;
  }
  .distro-row-item.distro-hdr {
    display: none;
  }
  .distro-row-item .btn-distro-get {
    grid-column: span 2;
  }
  .contact-channels {
    grid-template-columns: 1fr;
  }
  .footer-nav-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  :root {
    --header-ribbon-h: 26px;
    --header-deck-h: 48px;
    --header-h: 74px;
  }
  .hide-on-tablet {
    display: none !important;
  }
  .hide-on-mobile {
    display: none !important;
  }
  .brand-title {
    font-size: 0.95rem;
  }
  .brand-tag {
    display: none;
  }
  .btn-cta-nav span {
    display: none;
  }
  .btn-cta-nav {
    padding: 0 0.55rem;
  }
  .hero-headline {
    font-size: 1.85rem;
  }
  .metrics-quad {
    grid-template-columns: repeat(2, 1fr);
  }
  .qsolab-inputs {
    grid-template-columns: 1fr;
  }
  .outputs-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .bands-matrix-cells {
    grid-template-columns: repeat(3, 1fr);
  }
  .fund-actions-columns {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  .bands-matrix-cells {
    grid-template-columns: repeat(2, 1fr);
  }
  .metrics-quad {
    grid-template-columns: 1fr;
  }
}

@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;
  }
}

/* ===================================================================
   Accessibility Skip Links & Focus Infrastructure (WCAG 2.4.1)
   =================================================================== */

.skip-link {
  position: absolute;
  top: -120px;
  left: 1rem;
  background: var(--nixie-amber);
  color: #000 !important;
  padding: 0.6rem 1.2rem;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 0.85rem;
  text-decoration: none;
  z-index: 100000;
  border: 2px solid #fff;
  transition: top 0.15s ease-out;
}

.skip-link:focus {
  top: 1rem;
}

/* ===================================================================
   Hardware Validation Badges & Status Tags (As-Is Source of Truth)
   =================================================================== */

.status-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  padding: 0.15rem 0.55rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  font-weight: 700;
  border-radius: var(--radius-btn);
  white-space: nowrap;
}

.status-pill.confirmed {
  background: var(--phosphor-green-dim);
  color: var(--phosphor-green);
  border: 1px solid var(--phosphor-green);
}

.status-pill.partial {
  background: var(--nixie-amber-dim);
  color: var(--nixie-amber);
  border: 1px solid var(--nixie-amber);
}

.status-pill.experimental {
  background: var(--rf-cyan-dim);
  color: var(--rf-cyan);
  border: 1px solid var(--rf-cyan);
}

.status-pill.conditional {
  background: rgba(168, 85, 247, 0.14);
  color: #c084fc;
  border: 1px solid #a855f7;
}

.status-pill.hil-blocked {
  background: var(--overload-red-dim);
  color: var(--overload-red);
  border: 1px solid var(--overload-red);
}

.status-pill.planned {
  background: rgba(148, 163, 184, 0.14);
  color: var(--text-muted);
  border: 1px solid var(--border-machine);
}

/* ===================================================================
   Radio Protocol Matrix & Multi-Radio Hardware Grid
   =================================================================== */

.radio-matrix-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
  gap: 1.25rem;
  margin-top: 1.5rem;
}

.radio-card {
  background: var(--card-surface);
  border: 1px solid var(--border-machine);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: border-color var(--trans-fast), background-color var(--trans-fast);
}

.radio-card:hover {
  border-color: var(--border-active);
  background: var(--card-surface-hover);
}

.radio-card-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 0.5rem;
  margin-bottom: 0.75rem;
  padding-bottom: 0.6rem;
  border-bottom: 1px solid var(--border-subtle);
}

.radio-card-title {
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
}

.radio-card-desc {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.5;
  margin-bottom: 1rem;
}

.radio-specs-list {
  list-style: none;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  margin-bottom: 1rem;
}

.radio-specs-list li {
  display: flex;
  justify-content: space-between;
  padding: 0.25rem 0;
  border-bottom: 1px dashed var(--border-subtle);
}

.radio-specs-list li span:first-child {
  color: var(--text-muted);
}

.radio-specs-list li span:last-child {
  color: var(--text-primary);
  font-weight: 600;
}

.radio-card-footer {
  margin-top: auto;
  padding-top: 0.75rem;
  border-top: 1px solid var(--border-subtle);
  font-size: 0.75rem;
  font-family: var(--font-mono);
  color: var(--text-muted);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

/* ===================================================================
   Documentation & Subpage Layout Architecture (docs.html, changelog.html)
   =================================================================== */

.docs-container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

.docs-layout {
  display: grid;
  grid-template-columns: 280px minmax(0, 1fr);
  gap: 2rem;
  align-items: start;
}

.docs-sidebar {
  position: sticky;
  top: calc(var(--header-h) + 1rem);
  max-height: calc(100vh - var(--header-h) - 2rem);
  overflow-y: auto;
  background: var(--rack-faceplate);
  border: 1px solid var(--border-machine);
  padding: 1.25rem;
}

.docs-nav-group-title {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  text-transform: uppercase;
  color: var(--text-muted);
  letter-spacing: 0.08em;
  margin: 1.2rem 0 0.4rem;
  font-weight: 700;
}

.docs-nav-group-title:first-child {
  margin-top: 0;
}

.docs-nav-link {
  display: block;
  padding: 0.35rem 0.6rem;
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.85rem;
  border-left: 2px solid transparent;
  transition: all var(--trans-fast);
  margin-bottom: 0.15rem;
}

.docs-nav-link:hover, .docs-nav-link.active {
  color: var(--nixie-amber);
  border-left-color: var(--nixie-amber);
  background: var(--nixie-amber-dim);
}

.docs-content {
  background: var(--rack-faceplate);
  border: 1px solid var(--border-machine);
  padding: 2.25rem;
  min-width: 0;
}

.docs-article {
  margin-bottom: 3.5rem;
  scroll-margin-top: calc(var(--header-h) + 2rem);
}

.docs-article:last-child {
  margin-bottom: 1rem;
}

.docs-article h2 {
  font-family: var(--font-display);
  font-size: 1.65rem;
  color: var(--text-primary);
  margin-bottom: 1rem;
  padding-bottom: 0.6rem;
  border-bottom: 1px solid var(--border-machine);
}

.docs-article h3 {
  font-family: var(--font-display);
  font-size: 1.25rem;
  color: var(--text-primary);
  margin: 1.75rem 0 0.75rem;
}

.docs-article h4 {
  font-family: var(--font-display);
  font-size: 1.05rem;
  color: var(--text-primary);
  margin: 1.25rem 0 0.5rem;
}

.docs-article p {
  color: var(--text-secondary);
  margin-bottom: 1.15rem;
  line-height: 1.7;
  font-size: 0.95rem;
}

.docs-article ul, .docs-article ol {
  margin-left: 1.75rem;
  margin-bottom: 1.25rem;
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.docs-article li {
  margin-bottom: 0.45rem;
  line-height: 1.65;
}

.docs-article strong {
  color: var(--text-primary);
}

.callout {
  padding: 1rem 1.25rem;
  margin: 1.25rem 0;
  border-left: 3px solid;
  background: var(--card-surface);
}

.callout.info {
  border-color: var(--rf-cyan);
  background: var(--rf-cyan-dim);
}

.callout.warning {
  border-color: var(--nixie-amber);
  background: var(--nixie-amber-dim);
}

.callout.danger {
  border-color: var(--overload-red);
  background: var(--overload-red-dim);
}

.callout.success {
  border-color: var(--phosphor-green);
  background: var(--phosphor-green-dim);
}

.callout-title {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 0.8rem;
  text-transform: uppercase;
  margin-bottom: 0.35rem;
  letter-spacing: 0.04em;
}

.callout.info .callout-title { color: var(--rf-cyan); }
.callout.warning .callout-title { color: var(--nixie-amber); }
.callout.danger .callout-title { color: var(--overload-red); }
.callout.success .callout-title { color: var(--phosphor-green); }

.code-block {
  background: #040507;
  border: 1px solid var(--border-machine);
  padding: 1rem 1.25rem;
  margin: 1.15rem 0;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: #e2e8f0;
  line-height: 1.55;
}

.code-block code {
  font-family: inherit;
  color: inherit;
  background: transparent;
  padding: 0;
  border: none;
}

.breadcrumbs {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
}

.breadcrumbs a {
  color: var(--text-secondary);
  text-decoration: none;
}

.breadcrumbs a:hover {
  color: var(--nixie-amber);
}

.breadcrumbs .sep {
  color: var(--border-active);
}

.data-table-wrapper {
  overflow-x: auto;
  margin: 1.25rem 0;
  border: 1px solid var(--border-machine);
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.85rem;
  text-align: left;
}

.data-table th, .data-table td {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border-subtle);
}

.data-table th {
  background: var(--card-surface);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  color: var(--text-muted);
  letter-spacing: 0.05em;
}

.data-table td {
  color: var(--text-secondary);
}

.data-table tr:hover td {
  background: rgba(255, 255, 255, 0.02);
}

.data-table td strong {
  color: var(--text-primary);
}

.changelog-release-card {
  background: var(--card-surface);
  border: 1px solid var(--border-machine);
  padding: 1.75rem;
  margin-bottom: 2rem;
}

.changelog-hdr {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem;
  padding-bottom: 0.75rem;
  margin-bottom: 1rem;
  border-bottom: 1px solid var(--border-machine);
}

.changelog-version {
  font-family: var(--font-display);
  font-size: 1.45rem;
  font-weight: 800;
  color: var(--text-primary);
}

.changelog-date {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-muted);
}

.changelog-tag-badge {
  display: inline-block;
  padding: 0.15rem 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 700;
  background: var(--nixie-amber-dim);
  color: var(--nixie-amber);
  border: 1px solid var(--nixie-amber);
  margin-left: 0.5rem;
}

.changelog-category {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--rf-cyan);
  margin: 1.25rem 0 0.5rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.changelog-list {
  list-style: square;
  margin-left: 1.5rem;
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.changelog-list li {
  margin-bottom: 0.4rem;
  line-height: 1.6;
}

@media (max-width: 900px) {
  .docs-layout {
    grid-template-columns: 1fr;
  }
  .docs-sidebar {
    position: static;
    max-height: none;
    margin-bottom: 1.5rem;
  }
}