/* ==========================================================================
   PEIQIAN / NETWORK — TRI-COLUMN PRODUCT STUDIO
   Design System & Core Architecture
   ========================================================================== */

:root {
  /* Color System */
  --bg-canvas: #F7F3EA;
  --bg-col-a: #F1EEE6;
  --bg-col-b: #FBF9F4;
  --bg-col-c: #F5F2EB;
  --bg-white: #FFFFFF;
  --bg-footer: #EDE8DE;

  --text-primary: #18212A;
  --text-body: #49514D;
  --text-muted: #7D827D;
  
  --accent-green: #315E52;
  --accent-terracotta: #D96B45;
  --accent-blue: #294A68;
  --stone: #DED8CC;
  --border-color: #D7D3C9;
  --border-subtle: rgba(215, 211, 201, 0.7);

  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
  
  /* Layout Dimensions */
  --site-max-width: 1440px;
  --header-height: 72px;
  
  /* Transitions */
  --transition-fast: 0.2s cubic-bezier(0.16, 1, 0.3, 1);
  --transition-smooth: 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

/* Reset & Box Sizing */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  background-color: var(--bg-canvas);
  color: var(--text-primary);
  font-family: var(--font-sans);
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  line-height: 1.6;
  background-color: var(--bg-canvas);
  color: var(--text-body);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

img, svg, picture {
  display: block;
  max-width: 100%;
}

a {
  color: inherit;
  text-decoration: none;
  transition: color var(--transition-fast), border-color var(--transition-fast);
}

button {
  font: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

ul, ol {
  list-style: none;
}

/* ==========================================================================
   Structural Architecture: Three Column Grid Tracks
   ========================================================================== */

.studio-container {
  width: 100%;
  max-width: var(--site-max-width);
  margin: 0 auto;
  border-left: 1px solid var(--border-color);
  border-right: 1px solid var(--border-color);
}

/* Base Tri-Column Container */
.tri-row {
  display: grid;
  width: 100%;
  border-bottom: 1px solid var(--border-color);
  background-color: var(--bg-canvas);
}

/* Three persistent column tracks */
.col-a {
  background-color: var(--bg-col-a);
  border-right: 1px solid var(--border-color);
  padding: 40px 32px;
  display: flex;
  flex-direction: column;
  position: relative;
}

.col-b {
  background-color: var(--bg-col-b);
  border-right: 1px solid var(--border-color);
  padding: 40px 48px;
  display: flex;
  flex-direction: column;
}

.col-c {
  background-color: var(--bg-col-c);
  padding: 40px 32px;
  display: flex;
  flex-direction: column;
}

/* Specific Section Proportions on Desktop (Section 3 & rules) */
.ratio-hero {
  grid-template-columns: 22% 52% 26%;
  min-height: 580px;
}

.ratio-masthead {
  grid-template-columns: 22% 52% 26%;
}

.ratio-overview {
  grid-template-columns: 30% 50% 20%;
}

.ratio-global {
  grid-template-columns: 24% 56% 20%;
}

.ratio-devices {
  grid-template-columns: 18% 32% 50%;
}

.ratio-ai {
  grid-template-columns: 42% 24% 34%;
}

.ratio-media {
  grid-template-columns: 26% 48% 26%;
}

.ratio-plans {
  grid-template-columns: 22% 50% 28%;
}

.ratio-journal {
  grid-template-columns: 18% 60% 22%;
}

.ratio-notes {
  grid-template-columns: 28% 46% 26%;
}

.ratio-faq {
  grid-template-columns: 26% 54% 20%;
}

.ratio-footer {
  grid-template-columns: 24% 52% 24%;
}

.ratio-article {
  grid-template-columns: 18% 62% 20%;
}

.ratio-archive {
  grid-template-columns: 20% 58% 22%;
}

/* ==========================================================================
   Studio Masthead (Header)
   ========================================================================== */

.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: var(--bg-canvas);
  border-bottom: 1px solid var(--border-color);
  height: var(--header-height);
}

.masthead-row {
  display: grid;
  grid-template-columns: 22% 52% 26%;
  height: 100%;
  width: 100%;
  max-width: var(--site-max-width);
  margin: 0 auto;
  border-left: 1px solid var(--border-color);
  border-right: 1px solid var(--border-color);
}

.masthead-col-a {
  background-color: var(--bg-col-a);
  border-right: 1px solid var(--border-color);
  padding: 0 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.02em;
  display: flex;
  align-items: baseline;
  gap: 8px;
}

.brand-aux {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  font-weight: 500;
  letter-spacing: 0.05em;
}

.masthead-col-b {
  background-color: var(--bg-col-b);
  border-right: 1px solid var(--border-color);
  padding: 0 32px;
  display: flex;
  align-items: center;
}

.masthead-nav {
  display: flex;
  align-items: center;
  gap: 28px;
  width: 100%;
}

.masthead-nav a {
  font-size: 0.92rem;
  color: var(--text-body);
  font-weight: 500;
  padding: 6px 0;
  position: relative;
}

.masthead-nav a:hover,
.masthead-nav a.active {
  color: var(--text-primary);
}

.masthead-nav a.active::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 2px;
  background-color: var(--accent-green);
}

.masthead-col-c {
  background-color: var(--bg-col-c);
  padding: 0 32px;
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 20px;
}

.btn-link-plans {
  font-size: 0.88rem;
  color: var(--text-body);
  font-weight: 500;
}

.btn-link-plans:hover {
  color: var(--text-primary);
}

.btn-cta-masthead {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--bg-white);
  background-color: var(--accent-green);
  padding: 9px 18px;
  border-radius: 2px;
  transition: background-color var(--transition-fast), transform var(--transition-fast);
}

.btn-cta-masthead:hover {
  background-color: #23453c;
  color: var(--bg-white);
  transform: translateY(-1px);
}

/* Mobile Nav Toggle */
.mobile-nav-toggle {
  display: none;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  padding: 8px 12px;
  background-color: var(--bg-canvas);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
}

.mobile-menu-drawer {
  display: none;
  background-color: var(--bg-col-b);
  border-bottom: 1px solid var(--border-color);
  padding: 24px 20px;
}

.mobile-menu-drawer.open {
  display: block;
}

.mobile-menu-links {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.mobile-menu-links a {
  font-size: 1.05rem;
  font-weight: 500;
  color: var(--text-primary);
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border-subtle);
}

.mobile-menu-cta {
  margin-top: 16px;
  display: inline-block;
  text-align: center;
  width: 100%;
  padding: 12px;
  background-color: var(--accent-green);
  color: var(--bg-white);
  font-weight: 600;
}

/* ==========================================================================
   Index Typography & Studio Meta Elements
   ========================================================================== */

.index-num {
  font-family: var(--font-mono);
  font-size: 3.2rem;
  font-weight: 700;
  line-height: 1;
  color: var(--stone);
  letter-spacing: -0.04em;
  margin-bottom: 16px;
}

.index-tag {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 8px;
}

.index-sub {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.5;
}

.col-footer-meta {
  margin-top: auto;
  padding-top: 24px;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border-subtle);
}

/* ==========================================================================
   Hero Section
   ========================================================================== */

.hero-section {
  border-bottom: 1px solid var(--border-color);
}

.hero-col-a {
  justify-content: space-between;
}

.hero-col-a-top {
  display: flex;
  flex-direction: column;
}

.hero-service-badge {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--accent-green);
  font-weight: 600;
  letter-spacing: 0.08em;
  margin-top: 12px;
}

.hero-col-b {
  justify-content: center;
  padding-top: 60px;
  padding-bottom: 60px;
}

.hero-brand-name {
  font-size: 2.8rem;
  font-weight: 800;
  color: var(--text-primary);
  letter-spacing: -0.03em;
  line-height: 1.1;
  margin-bottom: 14px;
}

.hero-headline {
  font-size: 3.2rem;
  font-weight: 700;
  line-height: 1.15;
  color: var(--text-primary);
  letter-spacing: -0.02em;
  margin-bottom: 24px;
}

/* Single H1 for homepage */
.hero-h1-semantic {
  font-size: 1.55rem;
  font-weight: 600;
  line-height: 1.35;
  color: var(--accent-blue);
  margin-bottom: 22px;
}

.hero-geo-desc {
  font-size: 1.05rem;
  line-height: 1.75;
  color: var(--text-body);
  margin-bottom: 32px;
}

.hero-col-c {
  justify-content: space-between;
  background-color: var(--bg-col-c);
}

.summary-spec-list {
  display: flex;
  flex-direction: column;
  gap: 24px;
  margin-top: 12px;
}

.summary-spec-item {
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border-subtle);
}

.summary-spec-item:last-child {
  border-bottom: none;
}

.summary-spec-label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.12em;
  color: var(--text-muted);
  text-transform: uppercase;
}

.summary-spec-val {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-top: 4px;
}

.hero-cta-group {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-top: 32px;
}

.btn-hero-primary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 20px;
  background-color: var(--text-primary);
  color: var(--bg-white);
  font-weight: 600;
  font-size: 0.98rem;
  transition: background-color var(--transition-fast);
}

.btn-hero-primary:hover {
  background-color: var(--accent-green);
  color: var(--bg-white);
}

.btn-hero-secondary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 20px;
  border: 1px solid var(--border-color);
  background-color: var(--bg-white);
  color: var(--text-primary);
  font-weight: 600;
  font-size: 0.92rem;
  transition: border-color var(--transition-fast), background-color var(--transition-fast);
}

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

/* ==========================================================================
   Section 01: Network Overview
   ========================================================================== */

.sec-h2 {
  font-size: 2.2rem;
  font-weight: 700;
  line-height: 1.25;
  color: var(--text-primary);
  letter-spacing: -0.02em;
  margin-bottom: 20px;
}

.sec-p {
  font-size: 1.02rem;
  line-height: 1.75;
  color: var(--text-body);
  margin-bottom: 20px;
}

.sec-p:last-child {
  margin-bottom: 0;
}

.quick-nav-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.quick-nav-link {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 16px;
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-primary);
  letter-spacing: 0.05em;
  transition: border-color var(--transition-fast), transform var(--transition-fast);
}

.quick-nav-link:hover {
  border-color: var(--accent-green);
  color: var(--accent-green);
  transform: translateX(4px);
}

/* ==========================================================================
   Section 02: Global Regions
   ========================================================================== */

.region-stack {
  display: flex;
  flex-direction: column;
}

.region-block {
  padding: 24px 0;
  border-bottom: 1px solid var(--border-color);
}

.region-block:first-child {
  padding-top: 0;
}

.region-block:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.region-title {
  font-family: var(--font-mono);
  font-size: 0.95rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--accent-blue);
  margin-bottom: 12px;
  text-transform: uppercase;
}

.region-locations-list {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 24px;
}

.region-locations-list li {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 8px;
}

.region-locations-list li::before {
  content: "•";
  color: var(--accent-green);
  font-size: 1.2rem;
}

.region-count-stack {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.region-count-item {
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border-subtle);
}

.region-count-item:last-child {
  border-bottom: none;
}

.region-count-num {
  font-family: var(--font-mono);
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1;
}

.region-count-name {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-muted);
  letter-spacing: 0.08em;
  margin-top: 4px;
}

/* ==========================================================================
   Section 03: Devices
   ========================================================================== */

.device-large-list {
  display: flex;
  flex-direction: column;
}

.device-item {
  padding: 24px 0;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: baseline;
  justify-content: space-between;
}

.device-item:first-child {
  padding-top: 0;
}

.device-item:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.device-meta {
  display: flex;
  align-items: baseline;
  gap: 16px;
}

.device-num {
  font-family: var(--font-mono);
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--stone);
}

.device-name {
  font-size: 1.65rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--text-primary);
}

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

/* ==========================================================================
   Section 04: AI Section (Left Heavy: 42 / 24 / 34)
   ========================================================================== */

.ai-big-header {
  font-size: 3.5rem;
  font-weight: 800;
  line-height: 1;
  color: var(--text-primary);
  letter-spacing: -0.04em;
  margin-bottom: 8px;
}

.ai-tools-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-top: 24px;
}

.ai-tool-pill {
  padding: 14px 18px;
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  font-weight: 600;
  font-size: 0.96rem;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 10px;
}

.ai-tool-pill::before {
  content: "";
  width: 6px;
  height: 6px;
  background-color: var(--accent-green);
  border-radius: 50%;
}

.ai-workflow-list {
  display: flex;
  flex-direction: column;
  gap: 14px;
  margin-top: 16px;
}

.ai-workflow-list li {
  font-size: 0.95rem;
  color: var(--text-body);
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border-subtle);
  font-weight: 500;
}

.ai-internal-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-top: 24px;
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--accent-green);
  border-bottom: 1px solid var(--accent-green);
  padding-bottom: 4px;
}

.ai-internal-link:hover {
  color: #1b3830;
  border-color: #1b3830;
}

/* ==========================================================================
   Section 05: Media / Streaming
   ========================================================================== */

.media-services-stack {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.media-service-row {
  font-size: 1.85rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.02em;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.media-service-row:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.media-badge {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  font-weight: 500;
}

/* ==========================================================================
   Section 06: Plans / Pricing (Cross-Column Alignment)
   ========================================================================== */

.plan-rows-b {
  display: flex;
  flex-direction: column;
  width: 100%;
}

.plan-row-item-b {
  padding: 24px 0;
  border-bottom: 1px solid var(--border-color);
  min-height: 110px;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.plan-row-item-b:first-child {
  padding-top: 0;
}

.plan-row-item-b:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.plan-header-b {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin-bottom: 6px;
}

.plan-title-b {
  font-family: var(--font-mono);
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: 0.05em;
}

.plan-traffic-b {
  font-family: var(--font-mono);
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--accent-green);
}

.plan-focus-badge {
  font-size: 0.75rem;
  font-weight: 600;
  padding: 2px 8px;
  background-color: var(--accent-terracotta);
  color: var(--bg-white);
  border-radius: 2px;
}

.plan-desc-b {
  font-size: 0.92rem;
  color: var(--text-body);
}

/* Pricing Column C Synchronized Rows */
.plan-rows-c {
  display: flex;
  flex-direction: column;
  width: 100%;
}

.plan-row-item-c {
  padding: 24px 0;
  border-bottom: 1px solid var(--border-color);
  min-height: 110px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.plan-row-item-c:first-child {
  padding-top: 0;
}

.plan-row-item-c:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.plan-price-val {
  font-family: var(--font-mono);
  font-size: 1.55rem;
  font-weight: 700;
  color: var(--text-primary);
}

.plan-price-unit {
  font-size: 0.85rem;
  color: var(--text-muted);
  font-weight: 400;
}

.plan-cta-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 20px;
  font-size: 0.88rem;
  font-weight: 600;
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  transition: all var(--transition-fast);
}

.plan-cta-btn:hover {
  background-color: var(--text-primary);
  color: var(--bg-white);
  border-color: var(--text-primary);
}

.plan-cta-btn.focus {
  background-color: var(--accent-terracotta);
  color: var(--bg-white);
  border-color: var(--accent-terracotta);
}

.plan-cta-btn.focus:hover {
  background-color: #ba5330;
  border-color: #ba5330;
}

/* ==========================================================================
   Section 07: Journal / Blog (Editorial Stack & Cross-Col Metadata)
   ========================================================================== */

.journal-stack-b {
  display: flex;
  flex-direction: column;
}

.journal-entry-b {
  padding: 28px 0;
  border-bottom: 1px solid var(--border-color);
  min-height: 140px;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.journal-entry-b:first-child {
  padding-top: 0;
}

.journal-entry-b:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.journal-meta-b {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-muted);
  letter-spacing: 0.08em;
  margin-bottom: 8px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.journal-title-link {
  font-size: 1.25rem;
  font-weight: 700;
  line-height: 1.35;
  color: var(--text-primary);
  letter-spacing: -0.01em;
  margin-bottom: 8px;
}

.journal-title-link:hover {
  color: var(--accent-green);
}

.journal-summary-b {
  font-size: 0.92rem;
  line-height: 1.6;
  color: var(--text-body);
}

/* Journal Column C Synchronized Rows */
.journal-stack-c {
  display: flex;
  flex-direction: column;
}

.journal-entry-c {
  padding: 28px 0;
  border-bottom: 1px solid var(--border-color);
  min-height: 140px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.journal-entry-c:first-child {
  padding-top: 0;
}

.journal-entry-c:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.journal-c-details {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-muted);
  line-height: 1.4;
}

.journal-c-arrow {
  font-size: 1.35rem;
  font-weight: 300;
  color: var(--text-muted);
  transition: transform var(--transition-fast), color var(--transition-fast);
}

.journal-entry-c:hover .journal-c-arrow {
  transform: translate(2px, -2px);
  color: var(--accent-green);
}

/* ==========================================================================
   Section 08: User Notes
   ========================================================================== */

.notes-stack-b {
  display: flex;
  flex-direction: column;
}

.note-item-b {
  padding: 24px 0;
  border-bottom: 1px solid var(--border-color);
}

.note-item-b:first-child {
  padding-top: 0;
}

.note-item-b:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.note-label-b {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--accent-blue);
  margin-bottom: 8px;
}

.note-quote-b {
  font-size: 1.05rem;
  line-height: 1.65;
  color: var(--text-primary);
  font-style: normal;
}

.notes-stack-c {
  display: flex;
  flex-direction: column;
  gap: 36px;
  justify-content: space-around;
  height: 100%;
}

.note-tag-c {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--text-muted);
}

/* ==========================================================================
   Section 09: FAQ Section (Interactive & Schema-aligned)
   ========================================================================== */

.faq-list-b {
  display: flex;
  flex-direction: column;
}

.faq-item-b {
  border-bottom: 1px solid var(--border-color);
}

.faq-item-b:first-child {
  border-top: none;
}

.faq-summary {
  width: 100%;
  padding: 22px 0;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  text-align: left;
  background: none;
  border: none;
  cursor: pointer;
  gap: 16px;
}

.faq-num-q {
  display: flex;
  align-items: baseline;
  gap: 14px;
}

.faq-q-num {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--stone);
}

.faq-q-title {
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--text-primary);
  transition: color var(--transition-fast);
}

.faq-summary:hover .faq-q-title {
  color: var(--accent-green);
}

.faq-toggle-icon {
  font-family: var(--font-mono);
  font-size: 1.25rem;
  font-weight: 400;
  color: var(--text-muted);
  line-height: 1;
  min-width: 20px;
  text-align: right;
}

.faq-content {
  padding-bottom: 24px;
  padding-left: 32px;
  font-size: 0.98rem;
  line-height: 1.75;
  color: var(--text-body);
  display: none;
}

.faq-item-b.active .faq-content {
  display: block;
}

.faq-item-b.active .faq-toggle-icon::before {
  content: "—";
}

.faq-toggle-icon::before {
  content: "+";
}

.faq-item-b.active .faq-toggle-icon::before {
  content: "—";
}

/* ==========================================================================
   Compact Footer (Three Column Studio Footer)
   ========================================================================== */

.site-footer {
  background-color: var(--bg-footer);
  border-top: 1px solid var(--border-color);
  margin-top: auto;
}

.footer-container {
  width: 100%;
  max-width: var(--site-max-width);
  margin: 0 auto;
  border-left: 1px solid var(--border-color);
  border-right: 1px solid var(--border-color);
}

.footer-row {
  display: grid;
  grid-template-columns: 24% 52% 24%;
  min-height: 240px;
  max-height: 320px;
  border-bottom: 1px solid var(--border-color);
}

.footer-col-a {
  background-color: var(--bg-footer);
  border-right: 1px solid var(--border-color);
  padding: 36px 32px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.footer-brand {
  font-size: 1.3rem;
  font-weight: 800;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.footer-brand-aux {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-muted);
  letter-spacing: 0.08em;
  margin-top: 4px;
}

.footer-desc {
  font-size: 0.85rem;
  color: var(--text-body);
  line-height: 1.5;
  margin-top: 12px;
}

.footer-col-b {
  background-color: var(--bg-footer);
  border-right: 1px solid var(--border-color);
  padding: 36px 40px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
}

.footer-nav-block-title {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--text-muted);
  text-transform: uppercase;
  margin-bottom: 14px;
}

.footer-links-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-links-list a {
  font-size: 0.88rem;
  color: var(--text-body);
}

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

.footer-col-c {
  background-color: var(--bg-footer);
  padding: 36px 32px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.footer-cta-btn {
  display: inline-flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 18px;
  background-color: var(--accent-green);
  color: var(--bg-white);
  font-size: 0.88rem;
  font-weight: 600;
  border-radius: 2px;
  margin-top: 16px;
}

.footer-cta-btn:hover {
  background-color: #23453c;
  color: var(--bg-white);
}

/* Recommended Links Section 115 */
.footer-rec-row {
  padding: 18px 32px;
  border-bottom: 1px solid var(--border-color);
  background-color: var(--bg-footer);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 16px 32px;
  font-size: 0.82rem;
  color: var(--text-muted);
}

.footer-rec-title {
  font-family: var(--font-mono);
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--text-muted);
}

.footer-rec-links {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
}

.footer-rec-links a {
  color: var(--text-body);
  text-decoration: underline;
  text-underline-offset: 3px;
}

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

/* Footer Bottom Strip */
.footer-bottom-strip {
  padding: 16px 32px;
  background-color: var(--bg-footer);
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.8rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

.footer-legal-links {
  display: flex;
  gap: 20px;
}

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

/* ==========================================================================
   Editorial Article & Archive Styles (Articles & Categories)
   ========================================================================== */

/* Breadcrumbs */
.breadcrumb-nav {
  margin-bottom: 24px;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-muted);
}

.breadcrumb-nav ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
}

.breadcrumb-nav li::after {
  content: "/";
  margin-left: 8px;
  color: var(--stone);
}

.breadcrumb-nav li:last-child::after {
  content: "";
}

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

/* Article Sidebar TOC (Col A) */
.article-toc {
  position: sticky;
  top: 96px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.article-toc-title {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--text-muted);
  text-transform: uppercase;
  margin-bottom: 8px;
}

.article-toc-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.article-toc-list a {
  font-size: 0.85rem;
  color: var(--text-body);
  line-height: 1.4;
  padding-left: 8px;
  border-left: 2px solid transparent;
}

.article-toc-list a:hover {
  color: var(--accent-green);
  border-left-color: var(--accent-green);
}

/* Article Main Content (Col B) */
.article-h1 {
  font-size: 2.6rem;
  font-weight: 800;
  line-height: 1.2;
  color: var(--text-primary);
  letter-spacing: -0.03em;
  margin-bottom: 24px;
}

/* GEO Quick Answer Box (Section 84) */
.quick-answer {
  background-color: var(--bg-white);
  border-left: 4px solid var(--accent-green);
  border-top: 1px solid var(--border-color);
  border-right: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
  padding: 24px 28px;
  margin-bottom: 36px;
}

.quick-answer h2 {
  font-family: var(--font-mono);
  font-size: 0.95rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--accent-green);
  margin-bottom: 12px;
  text-transform: uppercase;
}

.quick-answer p {
  font-size: 1.05rem;
  line-height: 1.7;
  color: var(--text-primary);
  font-weight: 500;
}

/* Article Prose */
.article-prose {
  font-size: 1.05rem;
  line-height: 1.85;
  color: var(--text-body);
}

.article-prose h2 {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.02em;
  margin-top: 48px;
  margin-bottom: 18px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border-subtle);
}

.article-prose h3 {
  font-size: 1.35rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-top: 32px;
  margin-bottom: 14px;
}

.article-prose p {
  margin-bottom: 20px;
}

.article-prose ol {
  list-style: decimal;
  padding-left: 24px;
  margin-bottom: 24px;
}

.article-prose ol li {
  margin-bottom: 12px;
  line-height: 1.7;
}

.article-prose ul {
  list-style: disc;
  padding-left: 24px;
  margin-bottom: 24px;
}

.article-prose ul li {
  margin-bottom: 10px;
  line-height: 1.7;
}

.article-prose a {
  color: var(--accent-green);
  text-decoration: underline;
  text-underline-offset: 3px;
  font-weight: 500;
}

.article-prose a:hover {
  color: #1a3830;
}

/* Editorial Tables */
.article-table-wrap {
  width: 100%;
  overflow-x: auto;
  margin: 32px 0;
  border: 1px solid var(--border-color);
  background-color: var(--bg-white);
}

.article-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.92rem;
}

.article-table th {
  background-color: var(--bg-col-a);
  padding: 14px 18px;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.05em;
  font-weight: 700;
  color: var(--text-primary);
  border-bottom: 1px solid var(--border-color);
  border-right: 1px solid var(--border-subtle);
}

.article-table th:last-child {
  border-right: none;
}

.article-table td {
  padding: 14px 18px;
  border-bottom: 1px solid var(--border-subtle);
  border-right: 1px solid var(--border-subtle);
  color: var(--text-body);
}

.article-table td:last-child {
  border-right: none;
}

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

/* Article Sidebar Meta (Col C) */
.article-sidebar-meta {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.sidebar-meta-block {
  padding-bottom: 18px;
  border-bottom: 1px solid var(--border-subtle);
}

.sidebar-meta-block:last-child {
  border-bottom: none;
}

.sidebar-meta-label {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  color: var(--text-muted);
  text-transform: uppercase;
}

.sidebar-meta-val {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-top: 4px;
}

.sidebar-related-links {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-top: 10px;
}

.sidebar-related-links a {
  font-size: 0.88rem;
  line-height: 1.45;
  color: var(--text-body);
  padding-left: 8px;
  border-left: 2px solid var(--accent-blue);
}

.sidebar-related-links a:hover {
  color: var(--accent-green);
  border-left-color: var(--accent-green);
}

.sidebar-cta-card {
  padding: 20px;
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  margin-top: 12px;
}

.sidebar-cta-title {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 8px;
}

.sidebar-cta-desc {
  font-size: 0.85rem;
  color: var(--text-body);
  line-height: 1.5;
  margin-bottom: 16px;
}

.sidebar-cta-btn {
  display: block;
  text-align: center;
  padding: 10px 14px;
  background-color: var(--accent-green);
  color: var(--bg-white);
  font-size: 0.88rem;
  font-weight: 600;
  border-radius: 2px;
}

.sidebar-cta-btn:hover {
  background-color: #23453c;
  color: var(--bg-white);
}

/* Category Archive Specifics */
.archive-desc-box {
  padding: 24px 0;
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 32px;
}

.archive-desc-p {
  font-size: 1.1rem;
  line-height: 1.75;
  color: var(--text-body);
}

/* 404 Page Specifics */
.error-404-number {
  font-family: var(--font-mono);
  font-size: 6rem;
  font-weight: 800;
  line-height: 1;
  color: var(--accent-terracotta);
}

/* ==========================================================================
   Responsive Architecture & Breakpoints
   Mobile rules (Sections 135-143):
   Stack linearly into single column while preserving numbers, dividers, studio tags.
   ========================================================================== */

@media (max-width: 1080px) {
  .site-header {
    height: auto;
  }
  
  .masthead-row {
    grid-template-columns: 1fr auto;
    height: 64px;
  }
  
  .masthead-col-b,
  .masthead-col-c {
    display: none;
  }
  
  .masthead-col-a {
    border-right: none;
    width: 100%;
  }

  .mobile-nav-toggle {
    display: block;
  }

  /* Linear collapse for all multi-column rows */
  .tri-row,
  .ratio-hero,
  .ratio-overview,
  .ratio-global,
  .ratio-devices,
  .ratio-ai,
  .ratio-media,
  .ratio-plans,
  .ratio-journal,
  .ratio-notes,
  .ratio-faq,
  .ratio-footer,
  .ratio-article,
  .ratio-archive {
    grid-template-columns: 1fr;
    min-height: auto;
  }

  .col-a,
  .col-b,
  .col-c {
    border-right: none;
    border-bottom: 1px solid var(--border-color);
    padding: 32px 24px;
  }

  .col-c {
    border-bottom: none;
  }

  /* Hero adjustments */
  .hero-brand-name {
    font-size: 2.2rem;
  }

  .hero-headline {
    font-size: 2.3rem;
  }

  .hero-h1-semantic {
    font-size: 1.3rem;
  }

  /* Footer stack */
  .footer-row {
    grid-template-columns: 1fr;
    max-height: none;
    min-height: auto;
  }

  .footer-col-a,
  .footer-col-b,
  .footer-col-c {
    border-right: none;
    border-bottom: 1px solid var(--border-color);
  }

  .footer-col-b {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .footer-col-c {
    border-bottom: none;
  }

  .footer-bottom-strip {
    flex-direction: column;
    gap: 12px;
    align-items: flex-start;
  }
  
  .article-h1 {
    font-size: 2rem;
  }

  .article-toc {
    position: static;
  }
}

@media (max-width: 640px) {
  .col-a,
  .col-b,
  .col-c {
    padding: 24px 16px;
  }

  .hero-brand-name {
    font-size: 1.95rem;
  }

  .hero-headline {
    font-size: 2.05rem;
  }

  .sec-h2 {
    font-size: 1.65rem;
  }

  .index-num {
    font-size: 2.4rem;
  }

  .ai-tools-grid {
    grid-template-columns: 1fr;
  }

  .plan-row-item-c {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }

  .journal-entry-c {
    padding-top: 0;
  }
}

/* Accessibility: Focus visible */
:focus-visible {
  outline: 2px solid var(--accent-green);
  outline-offset: 2px;
}

/* Accessibility: prefers-reduced-motion */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *, *::before, *::after {
    transition: none !important;
    animation: none !important;
  }
}