/* ==========================================================================
   SUFE — Swiss International Style (Swiss Grid Standard)
   Palette:
     - Background: #FFFFFF
     - Surface:    #F3F4F6
     - Ink:        #0F172A
     - Accent:     #2563EB
   ========================================================================== */

:root {
  --bg-primary: #FFFFFF;
  --bg-secondary: #F3F4F6;
  --ink-primary: #0F172A;
  --ink-secondary: #475569;
  --ink-muted: #64748B;
  --accent: #2563EB;
  --accent-soft: rgba(37, 99, 235, 0.06);
  --status-ok: #10B981;
  --status-warn: #F59E0B;
  --border-light: #E2E8F0;
  --border-strong: #0F172A;
  --header-h: 64px;
  --max-w: 1440px;
  --font-sans: 'Inter', 'Noto Sans SC', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
}

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 16px);
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--ink-primary);
  line-height: 1.65;
  overflow-x: clip;
}

a {
  color: inherit;
  text-decoration: none;
}

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

ul, ol {
  list-style: none;
}

/* Container & Grid Scaffolding */
.container {
  width: 100%;
  max-width: var(--max-w);
  margin: 0 auto;
  border-left: 1px solid var(--border-light);
  border-right: 1px solid var(--border-light);
  background: var(--bg-primary);
}

.swiss-grid-3 {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  width: 100%;
}

.swiss-cell {
  padding: 2.25rem 2rem;
  border-bottom: 1px solid var(--border-light);
  border-right: 1px solid var(--border-light);
}

.swiss-cell:nth-child(3n) {
  border-right: none;
}

.mono {
  font-family: var(--font-mono);
}

.spec-tag {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
}

.spec-tag--dark {
  color: var(--ink-primary);
}

/* ==========================================================================
   Top Navigation Bar
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-h);
  background: rgba(255, 255, 255, 0.94);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-strong);
}

.header-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 2rem;
  border-left: 1px solid var(--border-light);
  border-right: 1px solid var(--border-light);
}

.brand-mark {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  font-weight: 800;
  font-size: 1.125rem;
  letter-spacing: -0.02em;
  color: var(--ink-primary);
}

.brand-square {
  width: 22px;
  height: 22px;
  background: var(--ink-primary);
  display: inline-grid;
  place-items: center;
  position: relative;
}

.brand-square::after {
  content: '';
  width: 8px;
  height: 8px;
  background: var(--accent);
}

.brand-sub {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 500;
  color: var(--ink-muted);
  border-left: 1px solid var(--border-light);
  padding-left: 0.75rem;
  letter-spacing: 0.06em;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.nav-link {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--ink-secondary);
  padding: 0.45rem 0.75rem;
  border: 1px solid transparent;
  transition: color 0.15s ease, border-color 0.15s ease, background-color 0.15s ease;
  white-space: nowrap;
}

.nav-link:hover,
.nav-link.is-active {
  color: var(--accent);
  background: var(--accent-soft);
}

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

.btn-ghost {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.625rem 1.25rem;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--ink-primary);
  background: transparent;
  border: 1px solid var(--border-strong);
  transition: background-color 0.18s ease, color 0.18s ease, border-color 0.18s ease;
}

.btn-ghost:hover {
  background: var(--ink-primary);
  color: var(--bg-primary);
}

.btn-ghost--accent {
  border-color: var(--accent);
  color: var(--accent);
}

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

.btn-solid {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--bg-primary);
  background: var(--accent);
  border: 1px solid var(--accent);
  transition: background-color 0.18s ease, transform 0.15s ease;
}

.btn-solid:hover {
  background: #1D4ED8;
}

.mobile-menu-btn {
  display: none;
  width: 38px;
  height: 38px;
  border: 1px solid var(--border-light);
  align-items: center;
  justify-content: center;
  color: var(--ink-primary);
}

/* ==========================================================================
   Hero Section with Kinetic Swiss Grid Canvas
   ========================================================================== */
.hero-section {
  position: relative;
  border-bottom: 1px solid var(--border-strong);
  overflow: hidden;
  background: var(--bg-primary);
}

.hero-canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 0;
}

.hero-content {
  position: relative;
  z-index: 1;
}

.hero-top-bar {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  border-bottom: 1px solid var(--border-light);
  background: rgba(255, 255, 255, 0.78);
}

.hero-meta-cell {
  padding: 0.875rem 2rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--ink-secondary);
  border-right: 1px solid var(--border-light);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.hero-meta-cell:last-child {
  border-right: none;
}

.status-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--status-ok);
  display: inline-block;
  flex-shrink: 0;
  box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.16);
}

.hero-main-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.hero-headline-box {
  grid-column: span 2;
  padding: 3.75rem 2rem 3.5rem;
  border-right: 1px solid var(--border-light);
  background: rgba(255, 255, 255, 0.72);
}

.hero-title {
  font-size: clamp(2.15rem, 3.8vw, 3.5rem);
  font-weight: 800;
  line-height: 1.12;
  letter-spacing: -0.03em;
  color: var(--ink-primary);
  margin: 1rem 0 1.25rem;
}

.hero-title .accent-word {
  color: var(--accent);
}

.hero-subtitle {
  font-size: 1.0625rem;
  color: var(--ink-secondary);
  max-width: 660px;
  line-height: 1.75;
  margin-bottom: 2rem;
}

.hero-cta-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 1rem;
}

.hero-highlights-box {
  padding: 2.5rem 2rem;
  background: rgba(243, 244, 246, 0.82);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 1.5rem;
}

.highlight-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.highlight-item {
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border-light);
}

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

.highlight-item h3 {
  font-size: 0.9375rem;
  font-weight: 700;
  margin-bottom: 0.25rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.highlight-item p {
  font-size: 0.8125rem;
  color: var(--ink-secondary);
}

.hero-kpi-strip {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  border-top: 1px solid var(--border-light);
  background: rgba(255, 255, 255, 0.88);
}

.kpi-cell {
  padding: 1.25rem 2rem;
  border-right: 1px solid var(--border-light);
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
}

.kpi-cell:last-child {
  border-right: none;
}

.kpi-label {
  font-size: 0.8125rem;
  color: var(--ink-secondary);
}

.kpi-value {
  font-family: var(--font-mono);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--ink-primary);
}

/* ==========================================================================
   Core 3-Column Swiss Standard Flow
   Col 1 (33.3% Sticky): Brand, Summary, Ghost CTA
   Col 2 (33.3%): Real-time Node Latency & Packet Loss List
   Col 3 (33.3%): Vertically Stacked Technical Spec Pricing Cards
   ========================================================================== */
.core-tri-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  border-bottom: 1px solid var(--border-strong);
  align-items: stretch;
}

.tri-col {
  border-right: 1px solid var(--border-light);
  min-width: 0;
}

.tri-col:last-child {
  border-right: none;
}

/* Column 1: Sticky Fixed Column */
.tri-col-brand {
  background: var(--bg-primary);
  position: relative;
}

.sticky-brand-panel {
  position: sticky;
  top: var(--header-h);
  padding: 2.75rem 2rem;
  display: flex;
  flex-direction: column;
  gap: 1.75rem;
}

.sticky-brand-title {
  font-size: clamp(3rem, 4.5vw, 4.25rem);
  font-weight: 900;
  letter-spacing: -0.04em;
  line-height: 0.95;
  color: var(--ink-primary);
}

.sticky-brand-code {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--accent);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom: 0.5rem;
  display: block;
}

.sticky-brand-desc {
  font-size: 0.9375rem;
  color: var(--ink-secondary);
  line-height: 1.75;
}

.sticky-spec-list {
  border-top: 1px solid var(--border-light);
  border-bottom: 1px solid var(--border-light);
  padding: 1rem 0;
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
}

.sticky-spec-row {
  display: flex;
  justify-content: space-between;
  font-size: 0.8125rem;
}

.sticky-spec-row span:first-child {
  color: var(--ink-muted);
  font-family: var(--font-mono);
}

.sticky-spec-row span:last-child {
  font-weight: 600;
  color: var(--ink-primary);
}

.btn-ghost-hero {
  width: 100%;
  padding: 0.95rem 1.5rem;
  font-size: 0.9375rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  border: 1px solid var(--border-strong);
  background: transparent;
  color: var(--ink-primary);
  display: inline-flex;
  align-items: center;
  justify-content: space-between;
  transition: all 0.18s ease;
}

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

.sticky-quick-jump {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  padding-top: 0.5rem;
}

.sticky-quick-jump a {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--ink-muted);
  padding: 0.25rem 0;
  transition: color 0.15s ease;
}

.sticky-quick-jump a:hover {
  color: var(--accent);
}

/* Column 2: Real-Time Node Monitor */
.tri-col-nodes {
  padding: 2.5rem 2rem;
  background: var(--bg-primary);
  transition: background-color 0.3s ease;
}

.col-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border-strong);
  margin-bottom: 1.25rem;
}

.col-header h2 {
  font-size: 1.375rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-top: 0.35rem;
}

.ping-refresh-btn {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  padding: 0.4rem 0.7rem;
  border: 1px solid var(--border-light);
  color: var(--ink-secondary);
  background: var(--bg-secondary);
  transition: all 0.15s ease;
  white-space: nowrap;
}

.ping-refresh-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.node-table-head {
  display: grid;
  grid-template-columns: 1.5fr 0.75fr 0.75fr;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-muted);
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--border-light);
}

.node-list {
  display: flex;
  flex-direction: column;
}

.node-row {
  display: grid;
  grid-template-columns: 1.5fr 0.75fr 0.75fr;
  align-items: center;
  padding: 0.8rem 0;
  border-bottom: 1px solid var(--border-light);
  font-size: 0.875rem;
}

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

.node-name-wrap {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  min-width: 0;
}

.node-title {
  font-weight: 600;
  color: var(--ink-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.node-route {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  color: var(--ink-muted);
  display: block;
}

.node-latency {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--ink-primary);
}

.node-loss {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--ink-secondary);
  text-align: right;
}

.node-footer-note {
  margin-top: 1.25rem;
  padding: 0.875rem 1rem;
  background: var(--bg-secondary);
  font-size: 0.75rem;
  color: var(--ink-secondary);
  font-family: var(--font-mono);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

/* Column 3: Pricing Spec Cards */
.tri-col-pricing {
  padding: 2.5rem 2rem;
  background: var(--bg-secondary);
  transition: background-color 0.3s ease;
}

.spec-card-stack {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.spec-card {
  background: var(--bg-primary);
  border: 1px solid var(--border-light);
  padding: 1.5rem;
  transition: border-color 0.18s ease, box-shadow 0.18s ease;
}

.spec-card:hover {
  border-color: var(--ink-primary);
}

.spec-card--featured {
  border: 1.5px solid var(--accent);
}

.spec-card-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--border-light);
  margin-bottom: 1rem;
}

.spec-badge {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  padding: 0.2rem 0.5rem;
  background: var(--bg-secondary);
  color: var(--ink-primary);
  font-weight: 600;
}

.spec-card--featured .spec-badge {
  background: var(--accent);
  color: var(--bg-primary);
}

.spec-price-row {
  display: flex;
  align-items: baseline;
  gap: 0.35rem;
  margin-bottom: 0.75rem;
}

.spec-price {
  font-family: var(--font-mono);
  font-size: 2.125rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--ink-primary);
}

.spec-cycle {
  font-size: 0.875rem;
  color: var(--ink-muted);
}

.spec-features {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
  margin-bottom: 1.25rem;
  font-size: 0.8125rem;
  color: var(--ink-secondary);
}

.spec-features li {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.spec-features li::before {
  content: '—';
  font-family: var(--font-mono);
  color: var(--accent);
  font-weight: 700;
}

.spec-card-btn {
  width: 100%;
  padding: 0.65rem 1rem;
  font-size: 0.8125rem;
  font-weight: 600;
  border: 1px solid var(--border-strong);
  display: inline-flex;
  align-items: center;
  justify-content: space-between;
  transition: all 0.15s ease;
}

.spec-card-btn:hover {
  background: var(--ink-primary);
  color: var(--bg-primary);
}

.spec-card--featured .spec-card-btn {
  border-color: var(--accent);
  color: var(--accent);
}

.spec-card--featured .spec-card-btn:hover {
  background: var(--accent);
  color: var(--bg-primary);
}

.col-pulse {
  background-color: rgba(37, 99, 235, 0.06) !important;
}

/* ==========================================================================
   Section Header Band (3-Column Swiss Alignment)
   ========================================================================== */
.section-band {
  border-bottom: 1px solid var(--border-strong);
}

.section-header-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  border-bottom: 1px solid var(--border-light);
  background: var(--bg-secondary);
}

.section-header-title {
  grid-column: span 2;
  padding: 2.25rem 2rem;
  border-right: 1px solid var(--border-light);
}

.section-header-title h2 {
  font-size: clamp(1.5rem, 2.5vw, 2rem);
  font-weight: 800;
  letter-spacing: -0.025em;
  margin-top: 0.35rem;
}

.section-header-meta {
  padding: 2.25rem 2rem;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 0.5rem;
  font-size: 0.875rem;
  color: var(--ink-secondary);
}

/* ==========================================================================
   Core Advantages (3-Column Grid)
   ========================================================================== */
.adv-card h3 {
  font-size: 1.0625rem;
  font-weight: 700;
  margin: 0.75rem 0 0.5rem;
}

.adv-card p {
  font-size: 0.875rem;
  color: var(--ink-secondary);
  line-height: 1.7;
}

.adv-metric {
  margin-top: 1.25rem;
  padding-top: 0.875rem;
  border-top: 1px solid var(--border-light);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--ink-muted);
  display: flex;
  justify-content: space-between;
}

/* ==========================================================================
   FAQ Section (3-Column Grid)
   ========================================================================== */
.faq-card {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.faq-toggle {
  width: 100%;
  text-align: left;
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 1rem;
  font-size: 1rem;
  font-weight: 700;
  color: var(--ink-primary);
  line-height: 1.45;
}

.faq-toggle .faq-icon {
  font-family: var(--font-mono);
  font-size: 1.125rem;
  color: var(--accent);
  flex-shrink: 0;
  transition: transform 0.2s ease;
}

.faq-card.is-open .faq-icon {
  transform: rotate(45deg);
}

.faq-answer {
  font-size: 0.875rem;
  color: var(--ink-secondary);
  line-height: 1.75;
  display: none;
  padding-top: 0.5rem;
  border-top: 1px solid var(--border-light);
}

.faq-card.is-open .faq-answer {
  display: block;
}

/* ==========================================================================
   Knowledge Base & Tutorials (3-Column Grid + Filter)
   ========================================================================== */
.kb-filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  padding: 1.25rem 2rem;
  border-bottom: 1px solid var(--border-light);
  background: var(--bg-primary);
}

.kb-filter-btn {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  padding: 0.45rem 0.9rem;
  border: 1px solid var(--border-light);
  color: var(--ink-secondary);
  background: var(--bg-primary);
  transition: all 0.15s ease;
}

.kb-filter-btn:hover,
.kb-filter-btn.is-active {
  border-color: var(--accent);
  background: var(--accent);
  color: var(--bg-primary);
}

.kb-card {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 1rem;
  transition: background-color 0.15s ease;
}

.kb-card:hover {
  background: var(--bg-secondary);
}

.kb-card.is-hidden {
  display: none;
}

.kb-card-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.kb-cat {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  padding: 0.2rem 0.5rem;
  border: 1px solid var(--border-light);
  color: var(--ink-secondary);
}

.kb-card h3 {
  font-size: 1.0625rem;
  font-weight: 700;
  line-height: 1.4;
  color: var(--ink-primary);
}

.kb-card p {
  font-size: 0.875rem;
  color: var(--ink-secondary);
  line-height: 1.68;
}

.kb-card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 0.875rem;
  border-top: 1px solid var(--border-light);
  font-family: var(--font-mono);
  font-size: 0.75rem;
}

.kb-read-link {
  color: var(--accent);
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
}

.kb-read-link:hover {
  text-decoration: underline;
}

/* ==========================================================================
   User Reviews (3-Column Grid)
   ========================================================================== */
.review-card {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 1.25rem;
}

.review-quote {
  font-size: 0.9375rem;
  color: var(--ink-primary);
  line-height: 1.75;
}

.review-meta {
  padding-top: 1rem;
  border-top: 1px solid var(--border-light);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.8125rem;
}

.review-author {
  font-weight: 700;
  color: var(--ink-primary);
}

.review-tag {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  color: var(--accent);
  background: var(--accent-soft);
  padding: 0.2rem 0.5rem;
}

/* ==========================================================================
   Footer (Strictly NO sitemap.xml or robots.txt links!)
   ========================================================================== */
.site-footer {
  background: var(--bg-secondary);
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.footer-cell {
  padding: 2.5rem 2rem;
  border-right: 1px solid var(--border-light);
}

.footer-cell:last-child {
  border-right: none;
}

.footer-cell h4 {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-muted);
  margin-bottom: 1rem;
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  font-size: 0.875rem;
}

.footer-links a:hover {
  color: var(--accent);
}

.footer-bottom {
  border-top: 1px solid var(--border-light);
  padding: 1.25rem 2rem;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--ink-muted);
}

/* ==========================================================================
   Standalone Knowledge Base Article Layout (3-Column Swiss Grid)
   ========================================================================== */
.article-tri-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  border-bottom: 1px solid var(--border-strong);
}

.article-sidebar-left {
  border-right: 1px solid var(--border-light);
  background: var(--bg-secondary);
}

.article-sticky-box {
  position: sticky;
  top: var(--header-h);
  padding: 2.25rem 2rem;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.article-main {
  grid-column: span 2;
  padding: 3rem 3rem 4rem;
  background: var(--bg-primary);
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--ink-muted);
  margin-bottom: 1.5rem;
}

.breadcrumb a:hover {
  color: var(--accent);
}

.article-header {
  padding-bottom: 1.75rem;
  border-bottom: 1px solid var(--border-strong);
  margin-bottom: 2rem;
}

.article-header h1 {
  font-size: clamp(1.75rem, 3vw, 2.5rem);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.025em;
  margin: 0.75rem 0 1rem;
}

.article-meta-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 1.25rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--ink-muted);
}

.article-body h2 {
  font-size: 1.3125rem;
  font-weight: 800;
  margin: 2rem 0 0.85rem;
  padding-left: 0.85rem;
  border-left: 3px solid var(--accent);
}

.article-body h3 {
  font-size: 1.0625rem;
  font-weight: 700;
  margin: 1.5rem 0 0.6rem;
}

.article-body p {
  font-size: 1rem;
  line-height: 1.85;
  color: #1E293B;
  margin-bottom: 1.15rem;
}

.article-body ul,
.article-body ol {
  margin: 0.75rem 0 1.25rem 1.25rem;
  list-style: disc;
  color: #1E293B;
}

.article-body li {
  margin-bottom: 0.5rem;
  line-height: 1.75;
}

.article-callout {
  margin: 1.75rem 0;
  padding: 1.25rem 1.5rem;
  background: var(--bg-secondary);
  border-left: 3px solid var(--border-strong);
  font-size: 0.9375rem;
}

.article-jump-box {
  margin-top: 2.5rem;
  padding: 1.75rem;
  border: 1px solid var(--border-strong);
  background: var(--bg-secondary);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.article-nav-links {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
  font-size: 0.8125rem;
}

.article-nav-links a {
  color: var(--ink-secondary);
  padding: 0.25rem 0;
  border-bottom: 1px solid transparent;
}

.article-nav-links a:hover {
  color: var(--accent);
}

/* ==========================================================================
   Responsive Breakpoints
   ========================================================================== */
@media (max-width: 1080px) {
  .main-nav {
    display: none;
    position: absolute;
    top: var(--header-h);
    left: 0;
    right: 0;
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border-strong);
    flex-direction: column;
    align-items: stretch;
    padding: 1rem 2rem;
    gap: 0.25rem;
  }

  .main-nav.is-open {
    display: flex;
  }

  .mobile-menu-btn {
    display: inline-flex;
  }

  .core-tri-grid,
  .swiss-grid-3,
  .hero-main-grid,
  .hero-top-bar,
  .hero-kpi-strip,
  .section-header-grid,
  .footer-grid,
  .article-tri-grid {
    grid-template-columns: 1fr;
  }

  .hero-headline-box,
  .section-header-title,
  .article-main {
    grid-column: span 1;
    border-right: none;
  }

  .swiss-cell,
  .tri-col,
  .hero-meta-cell,
  .kpi-cell,
  .footer-cell,
  .article-sidebar-left {
    border-right: none;
    border-bottom: 1px solid var(--border-light);
  }

  .sticky-brand-panel,
  .article-sticky-box {
    position: static;
  }
}

@media (max-width: 640px) {
  .header-inner,
  .swiss-cell,
  .tri-col-nodes,
  .tri-col-pricing,
  .sticky-brand-panel,
  .hero-headline-box,
  .hero-highlights-box,
  .article-main {
    padding-left: 1.25rem;
    padding-right: 1.25rem;
  }

  .brand-sub {
    display: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}