/* ==========================================================================
   贝贝云机场官网 (beibeiyunvpn.click) — Corporate SaaS Design System
   Style Reference: Clean Enterprise White/Slate + Electric Royal Blue (#0D55FF)
   ========================================================================== */

:root {
  --bg-page: #f7f9fc;
  --bg-radial: radial-gradient(circle at 50% 0%, #ffffff 0%, #f4f7fb 55%, #eef2f8 100%);
  --surface: #ffffff;
  --surface-muted: #f3f6fb;
  --surface-hover: #f8faff;
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;
  --border-light: #e2e8f0;
  --border-medium: #cbd5e1;

  --brand-blue: #0d55ff;
  --brand-blue-hover: #0044e6;
  --brand-blue-soft: #e8f0ff;
  --brand-blue-glow: rgba(13, 85, 255, 0.22);

  --status-green: #10b981;
  --status-green-soft: #ecfdf5;
  --status-amber: #f59e0b;
  --status-amber-soft: #fffbeb;

  --shadow-xs: 0 1px 2px rgba(15, 23, 42, 0.04);
  --shadow-sm: 0 4px 12px rgba(15, 23, 42, 0.05);
  --shadow-md: 0 12px 32px -4px rgba(15, 23, 42, 0.08), 0 4px 10px -2px rgba(15, 23, 42, 0.04);
  --shadow-lg: 0 24px 48px -12px rgba(13, 85, 255, 0.14), 0 8px 20px -4px rgba(15, 23, 42, 0.06);

  --radius-sm: 10px;
  --radius-md: 16px;
  --radius-lg: 22px;
  --radius-xl: 28px;

  --font-sans: "Inter", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-mono: "JetBrains Mono", "SFMono-Regular", Consolas, monospace;

  --container-max: 1200px;
  --transition: 0.24s cubic-bezier(0.22, 1, 0.36, 1);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  color: var(--text-primary);
  background: var(--bg-page);
  background-image: var(--bg-radial);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

a {
  color: var(--brand-blue);
  text-decoration: none;
  transition: color var(--transition);
}

a:hover {
  color: var(--brand-blue-hover);
}

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

/* Subtle Dynamic Grid + Ambient Glow Backdrop */
.ambient-backdrop {
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  overflow: hidden;
}

.ambient-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, rgba(148, 163, 184, 0.08) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(148, 163, 184, 0.08) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: radial-gradient(ellipse 75% 55% at 50% 15%, #000 35%, transparent 100%);
}

.ambient-orb {
  position: absolute;
  border-radius: 999px;
  filter: blur(80px);
  opacity: 0.45;
  animation: float-orb 16s ease-in-out infinite alternate;
}

.ambient-orb--one {
  width: 460px;
  height: 460px;
  top: -120px;
  left: 12%;
  background: radial-gradient(circle, rgba(13, 85, 255, 0.16), transparent 70%);
}

.ambient-orb--two {
  width: 400px;
  height: 400px;
  top: 220px;
  right: 8%;
  background: radial-gradient(circle, rgba(56, 189, 248, 0.15), transparent 70%);
  animation-delay: -6s;
}

@keyframes float-orb {
  0% { transform: translate3d(0, 0, 0) scale(1); }
  100% { transform: translate3d(28px, 34px, 0) scale(1.08); }
}

.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 24px;
}

/* Reading Progress Bar (Articles) */
.reading-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 3px;
  width: 0%;
  background: linear-gradient(90deg, var(--brand-blue), #38bdf8);
  z-index: 120;
  transition: width 0.1s linear;
}

/* ==========================================================================
   Navigation Header
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.86);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid rgba(226, 232, 240, 0.8);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
  gap: 20px;
}

.brand-logo {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

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

.brand-icon-box {
  width: 38px;
  height: 38px;
  border-radius: 11px;
  background: var(--brand-blue-soft);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  box-shadow: inset 0 0 0 1px rgba(13, 85, 255, 0.12);
}

.brand-icon-core {
  width: 20px;
  height: 20px;
  border-radius: 6px;
  background: var(--brand-blue);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: #ffffff;
}

.brand-tag {
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--brand-blue);
  background: var(--brand-blue-soft);
  padding: 2px 8px;
  border-radius: 999px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 6px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-links a {
  display: inline-flex;
  align-items: center;
  padding: 8px 14px;
  border-radius: 10px;
  color: var(--text-secondary);
  font-size: 0.93rem;
  font-weight: 500;
  transition: all var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--brand-blue);
  background: var(--brand-blue-soft);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-family: inherit;
  font-weight: 600;
  font-size: 0.94rem;
  padding: 11px 20px;
  border-radius: 12px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: all var(--transition);
  white-space: nowrap;
}

.btn-primary {
  background: var(--brand-blue);
  color: #ffffff;
  box-shadow: 0 6px 18px rgba(13, 85, 255, 0.25);
  position: relative;
  overflow: hidden;
}

.btn-primary::after {
  content: "";
  position: absolute;
  top: 0;
  left: -100%;
  width: 60%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.24), transparent);
  transition: left 0.55s ease;
}

.btn-primary:hover {
  background: var(--brand-blue-hover);
  color: #ffffff;
  transform: translateY(-1px);
  box-shadow: 0 10px 24px rgba(13, 85, 255, 0.32);
}

.btn-primary:hover::after {
  left: 140%;
}

.btn-secondary {
  background: var(--surface);
  color: var(--text-primary);
  border-color: var(--border-light);
  box-shadow: var(--shadow-xs);
}

.btn-secondary:hover {
  border-color: var(--brand-blue);
  color: var(--brand-blue);
  background: var(--surface-hover);
  transform: translateY(-1px);
}

.btn-soft {
  background: var(--surface-muted);
  color: var(--text-primary);
  border-color: var(--border-light);
}

.btn-soft:hover {
  background: var(--brand-blue-soft);
  color: var(--brand-blue);
  border-color: rgba(13, 85, 255, 0.25);
}

.btn-lg {
  padding: 14px 28px;
  font-size: 1rem;
  border-radius: 14px;
}

.mobile-menu-btn {
  display: none;
  background: var(--surface);
  border: 1px solid var(--border-light);
  border-radius: 10px;
  width: 40px;
  height: 40px;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  color: var(--text-primary);
}

/* ==========================================================================
   Hero Section (Corporate Card Inspired by Fig.1 + Dynamic Flourishes)
   ========================================================================== */
.hero-section {
  padding: 68px 0 64px;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.12fr 0.88fr;
  gap: 44px;
  align-items: center;
}

.status-pill {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 7px 15px;
  border-radius: 999px;
  background: var(--surface);
  border: 1px solid var(--border-light);
  box-shadow: var(--shadow-xs);
  font-size: 0.84rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 20px;
}

.pulse-dot {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--status-green);
  position: relative;
  display: inline-block;
}

.pulse-dot::after {
  content: "";
  position: absolute;
  inset: -4px;
  border-radius: 50%;
  border: 2px solid var(--status-green);
  animation: pulse-ring 2s cubic-bezier(0.24, 0, 0.38, 1) infinite;
}

@keyframes pulse-ring {
  0% { transform: scale(0.7); opacity: 0.9; }
  100% { transform: scale(1.9); opacity: 0; }
}

.hero-title {
  margin: 0 0 18px;
  font-size: clamp(2.1rem, 4vw, 3.15rem);
  line-height: 1.18;
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--text-primary);
}

.hero-title .highlight {
  color: var(--brand-blue);
  background: linear-gradient(120deg, #0d55ff 0%, #2563eb 60%, #0284c7 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-desc {
  margin: 0 0 28px;
  font-size: 1.08rem;
  color: var(--text-secondary);
  max-width: 600px;
}

.hero-cta-group {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-bottom: 30px;
}

.hero-metrics {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
  padding-top: 22px;
  border-top: 1px solid var(--border-light);
}

.metric-item strong {
  display: block;
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.metric-item span {
  font-size: 0.82rem;
  color: var(--text-muted);
}

/* Fig.1 Inspired Floating Corporate Portal Card */
.hero-card-wrapper {
  position: relative;
}

.corporate-portal-card {
  background: var(--surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-xl);
  padding: 34px 32px;
  box-shadow: var(--shadow-lg);
  position: relative;
  overflow: hidden;
  transition: transform var(--transition), box-shadow var(--transition);
}

.corporate-portal-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 30px 60px -14px rgba(13, 85, 255, 0.18), 0 10px 24px -6px rgba(15, 23, 42, 0.08);
}

.portal-card-head {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 14px;
}

.portal-badge-icon {
  width: 56px;
  height: 56px;
  border-radius: 16px;
  background: var(--brand-blue-soft);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.portal-badge-square {
  width: 28px;
  height: 28px;
  border-radius: 8px;
  background: var(--brand-blue);
  box-shadow: 0 4px 12px rgba(13, 85, 255, 0.35);
}

.portal-card-head h2 {
  margin: 0;
  font-size: 1.4rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.portal-card-head p {
  margin: 2px 0 0;
  font-size: 0.9rem;
  color: var(--text-muted);
}

.portal-subcopy {
  color: var(--text-secondary);
  font-size: 0.96rem;
  margin: 0 0 22px;
}

.portal-live-list {
  display: grid;
  gap: 10px;
  margin-bottom: 24px;
}

.portal-live-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 11px 14px;
  border-radius: 12px;
  background: var(--surface-muted);
  border: 1px solid rgba(226, 232, 240, 0.7);
  font-size: 0.88rem;
}

.portal-live-row .node-name {
  display: flex;
  align-items: center;
  gap: 9px;
  font-weight: 600;
  color: var(--text-primary);
}

.portal-live-row .ping-badge {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--status-green);
  background: var(--status-green-soft);
  padding: 2px 9px;
  border-radius: 999px;
}

.portal-cta-full {
  width: 100%;
  padding: 15px 24px;
  font-size: 1.02rem;
  border-radius: 14px;
}

.portal-card-foot {
  margin-top: 14px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* ==========================================================================
   Section Common Headers
   ========================================================================== */
.section {
  padding: 72px 0;
}

.section-alt {
  background: rgba(255, 255, 255, 0.72);
  border-top: 1px solid var(--border-light);
  border-bottom: 1px solid var(--border-light);
}

.section-header {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 44px;
}

.section-kicker {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 13px;
  border-radius: 999px;
  background: var(--brand-blue-soft);
  color: var(--brand-blue);
  font-size: 0.82rem;
  font-weight: 700;
  margin-bottom: 12px;
}

.section-title {
  margin: 0 0 12px;
  font-size: clamp(1.65rem, 3vw, 2.25rem);
  font-weight: 800;
  letter-spacing: -0.025em;
  color: var(--text-primary);
}

.section-subtitle {
  margin: 0;
  font-size: 1rem;
  color: var(--text-secondary);
}

/* ==========================================================================
   Node Status Monitor
   ========================================================================== */
.node-toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  margin-bottom: 22px;
  padding: 16px 20px;
  background: var(--surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-xs);
}

.node-filters {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.filter-chip {
  padding: 7px 14px;
  border-radius: 999px;
  border: 1px solid var(--border-light);
  background: var(--surface-muted);
  color: var(--text-secondary);
  font-size: 0.86rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
}

.filter-chip:hover {
  border-color: var(--brand-blue);
  color: var(--brand-blue);
}

.filter-chip.active {
  background: var(--brand-blue);
  color: #ffffff;
  border-color: var(--brand-blue);
}

.node-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.node-card {
  background: var(--surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  padding: 20px;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition);
}

.node-card:hover {
  transform: translateY(-3px);
  border-color: rgba(13, 85, 255, 0.32);
  box-shadow: var(--shadow-md);
}

.node-card-top {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 14px;
}

.node-title-wrap h3 {
  margin: 0 0 4px;
  font-size: 1.03rem;
  font-weight: 700;
}

.node-proto {
  font-size: 0.78rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

.node-online-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--status-green);
  background: var(--status-green-soft);
  padding: 4px 10px;
  border-radius: 999px;
  white-space: nowrap;
}

.node-stats-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 8px;
}

.latency-bar {
  height: 6px;
  width: 100%;
  background: var(--surface-muted);
  border-radius: 999px;
  overflow: hidden;
  margin-bottom: 12px;
}

.latency-fill {
  height: 100%;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--status-green), var(--brand-blue));
  transition: width 0.5s ease;
}

.node-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.node-tag {
  font-size: 0.74rem;
  font-weight: 600;
  color: var(--text-secondary);
  background: var(--surface-muted);
  padding: 3px 8px;
  border-radius: 6px;
}

/* ==========================================================================
   Core Advantages Grid
   ========================================================================== */
.advantages-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 20px;
}

.advantage-card {
  background: var(--surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 28px;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition);
}

.advantage-card:hover {
  transform: translateY(-4px);
  border-color: rgba(13, 85, 255, 0.3);
  box-shadow: var(--shadow-md);
}

.adv-icon {
  width: 48px;
  height: 48px;
  border-radius: 14px;
  background: var(--brand-blue-soft);
  color: var(--brand-blue);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 18px;
}

.advantage-card h3 {
  margin: 0 0 10px;
  font-size: 1.15rem;
  font-weight: 700;
}

.advantage-card p {
  margin: 0;
  font-size: 0.94rem;
  color: var(--text-secondary);
}

/* Platform Strip */
.platform-strip {
  margin-top: 28px;
  background: var(--surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 22px 26px;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  box-shadow: var(--shadow-xs);
}

.platform-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.platform-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 7px 14px;
  border-radius: 10px;
  background: var(--surface-muted);
  border: 1px solid var(--border-light);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-primary);
}

/* ==========================================================================
   Pricing Section (Faithful to Fig.2 Layout & Corporate Style)
   ========================================================================== */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 24px;
  align-items: stretch;
}

.pricing-card {
  background: var(--surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 34px 28px 28px;
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  position: relative;
  transition: all var(--transition);
}

.pricing-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.pricing-card.featured {
  border: 2px solid var(--brand-blue);
  box-shadow: var(--shadow-lg);
}

.pricing-badge {
  position: absolute;
  top: -15px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--brand-blue);
  color: #ffffff;
  font-size: 0.8rem;
  font-weight: 700;
  padding: 5px 18px;
  border-radius: 999px;
  box-shadow: 0 6px 14px rgba(13, 85, 255, 0.28);
  white-space: nowrap;
}

.pricing-name {
  margin: 0 0 6px;
  font-size: 1.45rem;
  font-weight: 800;
}

.pricing-desc {
  margin: 0 0 22px;
  font-size: 0.88rem;
  color: var(--text-muted);
  min-height: 24px;
}

.pricing-price {
  display: flex;
  align-items: baseline;
  gap: 4px;
  padding-bottom: 22px;
  margin-bottom: 22px;
  border-bottom: 1px solid var(--border-light);
}

.pricing-currency {
  color: var(--brand-blue);
  font-weight: 700;
  font-size: 1.25rem;
}

.pricing-amount {
  font-size: 2.65rem;
  font-weight: 800;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--text-primary);
}

.pricing-period {
  font-size: 0.95rem;
  color: var(--text-muted);
}

.pricing-features {
  list-style: none;
  margin: 0 0 28px;
  padding: 0;
  display: grid;
  gap: 13px;
  flex: 1;
}

.pricing-features li {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.94rem;
  color: var(--text-secondary);
}

.check-icon {
  color: var(--brand-blue);
  font-weight: 800;
  flex-shrink: 0;
}

.pricing-btn {
  width: 100%;
  padding: 13px 20px;
  border-radius: 12px;
  font-size: 0.96rem;
}

/* ==========================================================================
   50-Question FAQ Center
   ========================================================================== */
.faq-controls {
  background: var(--surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  padding: 18px 20px;
  margin-bottom: 22px;
  box-shadow: var(--shadow-xs);
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.faq-search-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
  justify-content: space-between;
}

.faq-search-input {
  flex: 1;
  min-width: 240px;
  padding: 11px 16px;
  border-radius: 10px;
  border: 1px solid var(--border-medium);
  font-family: inherit;
  font-size: 0.95rem;
  outline: none;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.faq-search-input:focus {
  border-color: var(--brand-blue);
  box-shadow: 0 0 0 3px rgba(13, 85, 255, 0.14);
}

.faq-count-badge {
  font-size: 0.86rem;
  font-weight: 600;
  color: var(--text-secondary);
  background: var(--surface-muted);
  padding: 7px 14px;
  border-radius: 999px;
}

.faq-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
  align-items: start;
}

.faq-item {
  background: var(--surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.faq-item[open] {
  border-color: rgba(13, 85, 255, 0.35);
  box-shadow: var(--shadow-sm);
}

.faq-item summary {
  list-style: none;
  cursor: pointer;
  padding: 16px 18px;
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--text-primary);
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
  user-select: none;
}

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

.faq-q-num {
  display: inline-block;
  min-width: 26px;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--brand-blue);
  background: var(--brand-blue-soft);
  padding: 2px 6px;
  border-radius: 6px;
  text-align: center;
  margin-right: 6px;
}

.faq-chevron {
  flex-shrink: 0;
  color: var(--text-muted);
  transition: transform 0.2s ease;
}

.faq-item[open] .faq-chevron {
  transform: rotate(180deg);
  color: var(--brand-blue);
}

.faq-answer {
  padding: 0 18px 16px;
  font-size: 0.9rem;
  color: var(--text-secondary);
  border-top: 1px solid var(--surface-muted);
  padding-top: 12px;
}

/* ==========================================================================
   Knowledge Base & Articles Grid
   ========================================================================== */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 20px;
}

.article-card {
  background: var(--surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  transition: all var(--transition);
}

.article-card:hover {
  transform: translateY(-4px);
  border-color: rgba(13, 85, 255, 0.35);
  box-shadow: var(--shadow-md);
}

.article-meta-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  margin-bottom: 12px;
}

.article-cat {
  font-size: 0.76rem;
  font-weight: 700;
  color: var(--brand-blue);
  background: var(--brand-blue-soft);
  padding: 3px 10px;
  border-radius: 999px;
}

.article-readtime {
  font-size: 0.78rem;
  color: var(--text-muted);
}

.article-card h3 {
  margin: 0 0 10px;
  font-size: 1.07rem;
  line-height: 1.45;
  font-weight: 700;
}

.article-card h3 a {
  color: var(--text-primary);
}

.article-card h3 a:hover {
  color: var(--brand-blue);
}

.article-card p {
  margin: 0 0 16px;
  font-size: 0.9rem;
  color: var(--text-secondary);
  flex: 1;
}

.article-keywords {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 14px;
}

.kw-pill {
  font-size: 0.73rem;
  color: var(--text-muted);
  background: var(--surface-muted);
  padding: 2px 8px;
  border-radius: 6px;
}

.article-readmore {
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--brand-blue);
  display: inline-flex;
  align-items: center;
  gap: 5px;
}

/* ==========================================================================
   Article Page Layout (Standalone 12 SEO/GEO Pages)
   ========================================================================== */
.article-page-wrap {
  padding: 36px 0 72px;
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-size: 0.86rem;
  color: var(--text-muted);
  margin-bottom: 24px;
}

.breadcrumb a {
  color: var(--text-secondary);
}

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

.article-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 320px;
  gap: 30px;
  align-items: start;
}

.article-main {
  background: var(--surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 38px 40px;
  box-shadow: var(--shadow-sm);
}

.article-header {
  padding-bottom: 24px;
  margin-bottom: 26px;
  border-bottom: 1px solid var(--border-light);
}

.article-header h1 {
  margin: 12px 0 14px;
  font-size: clamp(1.65rem, 3vw, 2.15rem);
  line-height: 1.3;
  font-weight: 800;
  letter-spacing: -0.02em;
}

.article-byline {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  font-size: 0.86rem;
  color: var(--text-muted);
}

.geo-summary-box {
  background: linear-gradient(135deg, #f0f5ff 0%, #f8faff 100%);
  border: 1px solid rgba(13, 85, 255, 0.2);
  border-left: 4px solid var(--brand-blue);
  border-radius: 14px;
  padding: 18px 20px;
  margin-bottom: 26px;
}

.geo-summary-box strong {
  display: block;
  color: var(--brand-blue);
  margin-bottom: 6px;
  font-size: 0.95rem;
}

.geo-summary-box p {
  margin: 0;
  font-size: 0.93rem;
  color: var(--text-secondary);
}

.article-body h2 {
  margin: 30px 0 14px;
  font-size: 1.38rem;
  font-weight: 700;
  color: var(--text-primary);
  padding-bottom: 8px;
  border-bottom: 1px solid var(--surface-muted);
}

.article-body h3 {
  margin: 22px 0 10px;
  font-size: 1.12rem;
  font-weight: 700;
  color: var(--text-primary);
}

.article-body p {
  margin: 0 0 16px;
  color: var(--text-secondary);
  font-size: 1rem;
  line-height: 1.82;
}

.article-body ul,
.article-body ol {
  margin: 0 0 18px;
  padding-left: 22px;
  color: var(--text-secondary);
}

.article-body li {
  margin-bottom: 8px;
  line-height: 1.75;
}

.article-table-wrap {
  overflow-x: auto;
  margin: 20px 0 24px;
  border: 1px solid var(--border-light);
  border-radius: 12px;
}

.article-body table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}

.article-body th,
.article-body td {
  padding: 12px 14px;
  text-align: left;
  border-bottom: 1px solid var(--border-light);
}

.article-body th {
  background: var(--surface-muted);
  font-weight: 700;
  color: var(--text-primary);
}

.article-cta-banner {
  margin: 30px 0;
  padding: 24px;
  border-radius: 16px;
  background: linear-gradient(135deg, #0d55ff 0%, #1d4ed8 100%);
  color: #ffffff;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.article-cta-banner h3 {
  margin: 0 0 4px;
  color: #ffffff;
  font-size: 1.15rem;
}

.article-cta-banner p {
  margin: 0;
  color: rgba(255, 255, 255, 0.88);
  font-size: 0.92rem;
}

.article-cta-banner .btn-white {
  background: #ffffff;
  color: var(--brand-blue);
  font-weight: 700;
  padding: 12px 22px;
  border-radius: 11px;
}

.article-cta-banner .btn-white:hover {
  background: #eff6ff;
}

.article-faq-section {
  margin-top: 34px;
  padding-top: 26px;
  border-top: 1px solid var(--border-light);
}

.article-faq-list {
  display: grid;
  gap: 12px;
}

.article-nav-links {
  margin-top: 30px;
  padding-top: 24px;
  border-top: 1px solid var(--border-light);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.article-nav-card {
  display: block;
  padding: 14px 16px;
  border: 1px solid var(--border-light);
  border-radius: 12px;
  background: var(--surface-muted);
  transition: all var(--transition);
}

.article-nav-card:hover {
  border-color: var(--brand-blue);
  background: var(--surface-hover);
}

.article-nav-card span {
  display: block;
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-bottom: 4px;
}

.article-nav-card strong {
  font-size: 0.92rem;
  color: var(--text-primary);
}

.related-articles-box {
  margin-top: 28px;
}

.related-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.related-mini-card {
  display: block;
  padding: 16px;
  border: 1px solid var(--border-light);
  border-radius: 12px;
  background: var(--surface);
  transition: all var(--transition);
}

.related-mini-card:hover {
  border-color: var(--brand-blue);
  transform: translateY(-2px);
}

.related-mini-card strong {
  display: block;
  font-size: 0.93rem;
  color: var(--text-primary);
  margin-bottom: 4px;
}

.related-mini-card span {
  font-size: 0.8rem;
  color: var(--brand-blue);
}

/* Article Sidebar */
.article-sidebar {
  position: sticky;
  top: 92px;
  display: grid;
  gap: 18px;
}

.sidebar-card {
  background: var(--surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  padding: 22px;
  box-shadow: var(--shadow-xs);
}

.sidebar-card h3 {
  margin: 0 0 12px;
  font-size: 1rem;
  font-weight: 700;
}

.sidebar-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.sidebar-list a {
  display: block;
  font-size: 0.88rem;
  color: var(--text-secondary);
  padding: 6px 10px;
  border-radius: 8px;
  background: var(--surface-muted);
}

.sidebar-list a:hover {
  background: var(--brand-blue-soft);
  color: var(--brand-blue);
}

/* ==========================================================================
   Footer
   ========================================================================== */
.site-footer {
  background: var(--surface);
  border-top: 1px solid var(--border-light);
  padding: 52px 0 28px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1fr;
  gap: 30px;
  margin-bottom: 36px;
}

.footer-brand p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin: 12px 0 0;
  max-width: 320px;
}

.footer-col h4 {
  margin: 0 0 14px;
  font-size: 0.95rem;
  font-weight: 700;
}

.footer-col ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 9px;
}

.footer-col a {
  font-size: 0.88rem;
  color: var(--text-secondary);
}

.footer-col a:hover {
  color: var(--brand-blue);
}

.footer-bottom {
  padding-top: 22px;
  border-top: 1px solid var(--border-light);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  font-size: 0.84rem;
  color: var(--text-muted);
}

/* Scroll Reveal Animation */
.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.55s ease, transform 0.55s ease;
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* ==========================================================================
   Responsive Breakpoints
   ========================================================================== */
@media (max-width: 1024px) {
  .hero-grid,
  .article-layout {
    grid-template-columns: 1fr;
  }
  .node-grid,
  .advantages-grid,
  .pricing-grid,
  .articles-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .footer-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .article-sidebar {
    position: static;
  }
}

@media (max-width: 768px) {
  .nav-links,
  .header-actions .btn-secondary {
    display: none;
  }
  .mobile-menu-btn {
    display: inline-flex;
  }
  .nav-links.open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 72px;
    left: 0;
    right: 0;
    background: var(--surface);
    border-bottom: 1px solid var(--border-light);
    padding: 16px 24px 20px;
    box-shadow: var(--shadow-md);
    align-items: stretch;
  }
  .hero-metrics {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .node-grid,
  .advantages-grid,
  .pricing-grid,
  .faq-grid,
  .articles-grid,
  .article-nav-links,
  .related-grid,
  .footer-grid {
    grid-template-columns: 1fr;
  }
  .article-main {
    padding: 24px 20px;
  }
}