:root {
  --bg-deep: #040914;
  --bg-navy: #081326;
  --surface: rgba(11, 23, 46, 0.72);
  --surface-strong: rgba(13, 27, 54, 0.9);
  --surface-hover: rgba(18, 36, 70, 0.85);
  --border-subtle: rgba(74, 158, 255, 0.18);
  --border-glow: rgba(0, 242, 254, 0.48);
  --text-main: #edf4ff;
  --text-muted: #9eb4d6;
  --text-dim: #738cb3;
  --cyan: #00f2fe;
  --sky: #38bdf8;
  --indigo: #5b73ff;
  --emerald: #22d3aa;
  --amber: #fbbf24;
  --grad-brand: linear-gradient(135deg, #00f2fe 0%, #38bdf8 48%, #5b73ff 100%);
  --grad-soft: linear-gradient(135deg, rgba(0, 242, 254, 0.14), rgba(91, 115, 255, 0.14));
  --shadow-card: 0 20px 50px rgba(2, 8, 22, 0.55);
  --shadow-glow: 0 0 36px rgba(0, 242, 254, 0.18);
  --radius-sm: 10px;
  --radius-md: 16px;
  --radius-lg: 22px;
  --container: 1200px;
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
}

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

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

body {
  margin: 0;
  font-family: var(--font-sans);
  background-color: var(--bg-deep);
  color: var(--text-main);
  line-height: 1.7;
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--sky);
  text-decoration: none;
  transition: color 0.2s ease, opacity 0.2s ease, transform 0.2s ease;
}

a:hover {
  color: var(--cyan);
}

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

/* =========================================================
   Pure-CSS Dynamic Animated Background Stage
   ========================================================= */
.bg-stage {
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  overflow: hidden;
  background:
    radial-gradient(circle at 18% 15%, rgba(0, 242, 254, 0.08), transparent 42%),
    radial-gradient(circle at 82% 85%, rgba(91, 115, 255, 0.1), transparent 45%),
    linear-gradient(160deg, #030711 0%, #071225 52%, #050c1b 100%);
}

.bg-grid {
  position: absolute;
  inset: -120px;
  background-image:
    linear-gradient(rgba(56, 189, 248, 0.065) 1px, transparent 1px),
    linear-gradient(90deg, rgba(56, 189, 248, 0.065) 1px, transparent 1px);
  background-size: 64px 64px;
  mask-image: radial-gradient(ellipse 80% 70% at 50% 35%, #000 35%, transparent 100%);
  -webkit-mask-image: radial-gradient(ellipse 80% 70% at 50% 35%, #000 35%, transparent 100%);
  animation: latticeDrift 28s linear infinite;
}

.aurora {
  position: absolute;
  border-radius: 999px;
  filter: blur(75px);
  opacity: 0.46;
  will-change: transform;
}

.aurora-1 {
  width: 560px;
  height: 560px;
  top: -160px;
  left: -120px;
  background: radial-gradient(circle, rgba(0, 242, 254, 0.36) 0%, rgba(56, 189, 248, 0.08) 65%, transparent 100%);
  animation: auroraOrbitA 22s ease-in-out infinite alternate;
}

.aurora-2 {
  width: 620px;
  height: 620px;
  top: 25%;
  right: -180px;
  background: radial-gradient(circle, rgba(91, 115, 255, 0.38) 0%, rgba(56, 189, 248, 0.06) 65%, transparent 100%);
  animation: auroraOrbitB 26s ease-in-out infinite alternate;
}

.aurora-3 {
  width: 500px;
  height: 500px;
  bottom: -180px;
  left: 28%;
  background: radial-gradient(circle, rgba(34, 211, 170, 0.24) 0%, rgba(0, 242, 254, 0.05) 68%, transparent 100%);
  animation: auroraOrbitC 20s ease-in-out infinite alternate;
}

.fiber-beam {
  position: absolute;
  height: 2px;
  width: 280px;
  background: linear-gradient(90deg, transparent 0%, rgba(0, 242, 254, 0.78) 55%, #ffffff 100%);
  box-shadow: 0 0 14px rgba(0, 242, 254, 0.65);
  border-radius: 999px;
  opacity: 0;
}

.fiber-1 {
  top: 18%;
  left: -300px;
  animation: fiberSweep 9s linear infinite;
}

.fiber-2 {
  top: 48%;
  left: -320px;
  width: 340px;
  animation: fiberSweep 12s linear infinite 3.5s;
}

.fiber-3 {
  top: 76%;
  left: -260px;
  width: 240px;
  background: linear-gradient(90deg, transparent 0%, rgba(91, 115, 255, 0.8) 60%, #a5f3fc 100%);
  animation: fiberSweep 10.5s linear infinite 6s;
}

.node-beacon {
  position: absolute;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--cyan);
  box-shadow: 0 0 12px var(--cyan);
}

.node-beacon::after {
  content: "";
  position: absolute;
  inset: -10px;
  border-radius: 50%;
  border: 1px solid rgba(0, 242, 254, 0.55);
  animation: beaconPulse 3.6s ease-out infinite;
}

.beacon-1 { top: 22%; left: 14%; }
.beacon-2 { top: 34%; right: 12%; }
.beacon-2::after { animation-delay: 1.1s; }
.beacon-3 { bottom: 26%; left: 22%; }
.beacon-3::after { animation-delay: 2.2s; }
.beacon-4 { bottom: 18%; right: 18%; }
.beacon-4::after { animation-delay: 0.6s; }

@keyframes latticeDrift {
  0% { transform: translate3d(0, 0, 0); }
  100% { transform: translate3d(64px, 64px, 0); }
}

@keyframes auroraOrbitA {
  0% { transform: translate3d(0, 0, 0) scale(1); }
  50% { transform: translate3d(90px, 70px, 0) scale(1.12); }
  100% { transform: translate3d(30px, 130px, 0) scale(0.95); }
}

@keyframes auroraOrbitB {
  0% { transform: translate3d(0, 0, 0) scale(1); }
  50% { transform: translate3d(-110px, -60px, 0) scale(1.08); }
  100% { transform: translate3d(-50px, 80px, 0) scale(0.94); }
}

@keyframes auroraOrbitC {
  0% { transform: translate3d(0, 0, 0) scale(1); }
  100% { transform: translate3d(100px, -90px, 0) scale(1.15); }
}

@keyframes fiberSweep {
  0% { transform: translate3d(0, 0, 0); opacity: 0; }
  8% { opacity: 0.72; }
  85% { opacity: 0.5; }
  100% { transform: translate3d(calc(100vw + 420px), 0, 0); opacity: 0; }
}

@keyframes beaconPulse {
  0% { transform: scale(0.4); opacity: 0.85; }
  100% { transform: scale(2.8); opacity: 0; }
}

/* =========================================================
   Dynamic World Map & Global POP Node Layer
   ========================================================= */
.world-map-wrap {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0.82;
  mask-image: radial-gradient(ellipse 92% 86% at 50% 46%, #000 58%, transparent 100%);
  -webkit-mask-image: radial-gradient(ellipse 92% 86% at 50% 46%, #000 58%, transparent 100%);
}

.world-map-svg {
  width: 100%;
  height: 100%;
  max-width: none;
  object-fit: cover;
  filter: drop-shadow(0 0 18px rgba(0, 242, 254, 0.08));
}

.map-graticule {
  stroke: rgba(56, 189, 248, 0.08);
  stroke-width: 0.7;
  fill: none;
}

.map-land {
  fill: rgba(14, 37, 74, 0.6);
  stroke: rgba(56, 189, 248, 0.34);
  stroke-width: 1.05;
  stroke-linejoin: round;
}

.map-arc-base {
  fill: none;
  stroke: rgba(56, 189, 248, 0.22);
  stroke-width: 1.4;
}

.map-arc-flow {
  fill: none;
  stroke: url(#mapRouteGrad);
  stroke-width: 2;
  stroke-linecap: round;
  stroke-dasharray: 12 22;
  animation: mapRouteFlow 5s linear infinite;
}

.map-arc-flow.arc-alt {
  stroke-dasharray: 16 26;
  animation-duration: 6.8s;
  animation-direction: reverse;
}

.map-node .node-pulse {
  fill: rgba(0, 242, 254, 0.16);
  stroke: rgba(0, 242, 254, 0.72);
  stroke-width: 1.3;
  transform-box: fill-box;
  transform-origin: center;
  animation: mapNodePing 3.2s ease-out infinite;
}

.map-node.delay-1 .node-pulse { animation-delay: 0.6s; }
.map-node.delay-2 .node-pulse { animation-delay: 1.2s; }
.map-node.delay-3 .node-pulse { animation-delay: 1.8s; }
.map-node.delay-4 .node-pulse { animation-delay: 2.4s; }

.map-node .node-halo {
  fill: rgba(0, 242, 254, 0.28);
}

.map-node .node-dot {
  fill: #00f2fe;
  stroke: #e0f9ff;
  stroke-width: 1.2;
}

.map-node.node-hub .node-dot {
  fill: #22d3aa;
}

.map-node .node-label-bg {
  fill: rgba(5, 13, 30, 0.78);
  stroke: rgba(0, 242, 254, 0.34);
  stroke-width: 0.85;
}

.map-node .node-label {
  fill: #d8eeff;
  font-family: var(--font-sans);
  font-size: 10.5px;
  font-weight: 700;
  letter-spacing: 0.02em;
}

@keyframes mapRouteFlow {
  from { stroke-dashoffset: 152; }
  to { stroke-dashoffset: 0; }
}

@keyframes mapNodePing {
  0% { transform: scale(0.6); opacity: 0.9; }
  75% { transform: scale(2.65); opacity: 0.12; }
  100% { transform: scale(3.1); opacity: 0; }
}

@media (prefers-reduced-motion: reduce) {
  .bg-grid,
  .aurora,
  .fiber-beam,
  .node-beacon::after,
  .map-arc-flow,
  .map-node .node-pulse {
    animation: none !important;
  }
}

/* =========================================================
   Layout Containers & Utilities
   ========================================================= */
.container {
  width: min(var(--container), calc(100% - 2rem));
  margin-inline: auto;
}

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

.section-header {
  text-align: center;
  max-width: 760px;
  margin: 0 auto 2.75rem;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.34rem 0.9rem;
  border-radius: 999px;
  font-size: 0.82rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--cyan);
  background: rgba(0, 242, 254, 0.1);
  border: 1px solid rgba(0, 242, 254, 0.28);
  margin-bottom: 0.9rem;
}

.section-title {
  margin: 0 0 0.85rem;
  font-size: clamp(1.65rem, 3vw, 2.35rem);
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: -0.01em;
}

.section-desc {
  margin: 0;
  color: var(--text-muted);
  font-size: 1.02rem;
}

.gradient-text {
  background: var(--grad-brand);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

/* =========================================================
   Buttons
   ========================================================= */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.82rem 1.55rem;
  border-radius: 12px;
  font-weight: 700;
  font-size: 0.96rem;
  cursor: pointer;
  border: 1px solid transparent;
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease, background 0.2s ease;
  text-align: center;
  white-space: nowrap;
}

.btn-primary {
  background: var(--grad-brand);
  color: #031122;
  box-shadow: 0 10px 28px rgba(0, 242, 254, 0.26);
}

.btn-primary:hover {
  color: #020c1a;
  transform: translateY(-2px);
  box-shadow: 0 14px 34px rgba(0, 242, 254, 0.38);
}

.btn-secondary {
  background: rgba(15, 31, 61, 0.78);
  color: var(--text-main);
  border-color: var(--border-subtle);
}

.btn-secondary:hover {
  color: var(--cyan);
  border-color: var(--border-glow);
  background: rgba(20, 41, 80, 0.92);
  transform: translateY(-2px);
}

.btn-sm {
  padding: 0.56rem 1.15rem;
  font-size: 0.88rem;
  border-radius: 10px;
}

.btn-block {
  width: 100%;
}

/* =========================================================
   Top Navigation Header (Left-Aligned Official Brand Logo)
   ========================================================= */
.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background: rgba(5, 11, 24, 0.78);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  border-bottom: 1px solid rgba(56, 189, 248, 0.14);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.25rem;
  min-height: 74px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  flex-shrink: 0;
  color: var(--text-main);
}

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

.brand-logo {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  box-shadow: 0 0 20px rgba(11, 130, 255, 0.42);
  flex-shrink: 0;
}

.brand-meta {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
}

.brand-name {
  font-size: 1.18rem;
  font-weight: 800;
  letter-spacing: -0.01em;
}

.brand-domain {
  font-size: 0.75rem;
  color: var(--cyan);
  font-family: var(--font-mono);
  letter-spacing: 0.03em;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 1.35rem;
}

.main-nav a {
  color: var(--text-muted);
  font-size: 0.93rem;
  font-weight: 500;
  white-space: nowrap;
}

.main-nav a:hover,
.main-nav a[aria-current="page"] {
  color: var(--cyan);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-shrink: 0;
}

.mobile-nav {
  display: none;
  position: relative;
}

.mobile-nav summary {
  list-style: none;
  cursor: pointer;
  padding: 0.5rem 0.85rem;
  border-radius: 10px;
  background: rgba(15, 31, 61, 0.85);
  border: 1px solid var(--border-subtle);
  color: var(--text-main);
  font-size: 0.9rem;
  font-weight: 600;
}

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

.mobile-drawer {
  position: absolute;
  right: 0;
  top: calc(100% + 0.65rem);
  width: 240px;
  padding: 0.85rem;
  border-radius: var(--radius-md);
  background: rgba(7, 16, 34, 0.97);
  border: 1px solid var(--border-glow);
  box-shadow: var(--shadow-card);
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
}

.mobile-drawer a {
  padding: 0.55rem 0.75rem;
  border-radius: 8px;
  color: var(--text-main);
  font-size: 0.93rem;
}

.mobile-drawer a:hover {
  background: rgba(0, 242, 254, 0.1);
  color: var(--cyan);
}

@media (max-width: 980px) {
  .main-nav {
    display: none;
  }
  .mobile-nav {
    display: block;
  }
}

/* =========================================================
   Hero Section
   ========================================================= */
.hero {
  padding: 5.5rem 0 4.25rem;
}

.hero-centered {
  max-width: 840px;
  margin-inline: auto;
  text-align: center;
  padding: 2.2rem 1.75rem;
  border-radius: 28px;
  background: radial-gradient(ellipse at center, rgba(4, 9, 20, 0.72) 0%, rgba(4, 9, 20, 0.35) 68%, transparent 100%);
}

.hero-title {
  margin: 0 0 1.2rem;
  font-size: clamp(2.1rem, 4.4vw, 3.35rem);
  font-weight: 900;
  line-height: 1.18;
  letter-spacing: -0.02em;
  text-shadow: 0 4px 24px rgba(2, 6, 18, 0.85);
}

.hero-lead {
  margin: 0 auto 1.9rem;
  font-size: 1.09rem;
  color: #c5d7f2;
  max-width: 680px;
  text-shadow: 0 2px 14px rgba(2, 6, 18, 0.9);
}

.hero-cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.9rem;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.85rem;
}

.hero-badges {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.65rem;
}

.badge-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.36rem 0.78rem;
  border-radius: 999px;
  background: rgba(13, 27, 54, 0.78);
  border: 1px solid var(--border-subtle);
  color: var(--text-muted);
  font-size: 0.82rem;
}

.badge-chip strong {
  color: var(--cyan);
}

/* =========================================================
   Feature / Node Highlights Grid
   ========================================================= */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1.35rem;
}

.glass-card {
  background: var(--surface);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.55rem;
  box-shadow: var(--shadow-card);
  transition: transform 0.25s ease, border-color 0.25s ease, background 0.25s ease;
}

.glass-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-glow);
  background: var(--surface-hover);
}

.card-icon {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  display: grid;
  place-items: center;
  background: var(--grad-soft);
  border: 1px solid rgba(0, 242, 254, 0.28);
  color: var(--cyan);
  font-weight: 800;
  font-size: 1.1rem;
  margin-bottom: 1rem;
}

.glass-card h3 {
  margin: 0 0 0.55rem;
  font-size: 1.12rem;
  font-weight: 700;
}

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

@media (max-width: 860px) {
  .features-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 580px) {
  .features-grid {
    grid-template-columns: 1fr;
  }
}

/* =========================================================
   Pricing Section — Strictly Same Row (所有价格要同排)
   Pure CSS Billing Cycle Toggle
   ========================================================= */
.billing-switch-wrap {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.billing-radio {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.billing-tabs {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.35rem;
  border-radius: 14px;
  background: rgba(8, 19, 38, 0.9);
  border: 1px solid var(--border-subtle);
  margin-bottom: 2.2rem;
}

.billing-tab {
  cursor: pointer;
  padding: 0.55rem 1.25rem;
  border-radius: 10px;
  font-size: 0.92rem;
  font-weight: 700;
  color: var(--text-muted);
  transition: background 0.2s ease, color 0.2s ease;
  user-select: none;
}

.billing-tab .save-tag {
  display: inline-block;
  margin-left: 0.35rem;
  padding: 0.1rem 0.45rem;
  border-radius: 999px;
  font-size: 0.72rem;
  background: rgba(34, 211, 170, 0.16);
  color: var(--emerald);
}

#bill-annual:checked ~ .billing-tabs label[for="bill-annual"],
#bill-monthly:checked ~ .billing-tabs label[for="bill-monthly"] {
  background: var(--grad-brand);
  color: #031122;
}

#bill-annual:checked ~ .billing-tabs label[for="bill-annual"] .save-tag {
  background: rgba(3, 17, 34, 0.18);
  color: #031122;
}

.price-monthly-view {
  display: none;
}

#bill-monthly:checked ~ .pricing-row .price-annual-view {
  display: none;
}

#bill-monthly:checked ~ .pricing-row .price-monthly-view {
  display: block;
}

/* Strictly 1 horizontal row across all desktop/tablet/mobile viewports */
.pricing-row {
  width: 100%;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1.5rem;
  align-items: stretch;
}

.pricing-card {
  position: relative;
  display: flex;
  flex-direction: column;
  background: var(--surface-strong);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 2rem 1.65rem 1.75rem;
  box-shadow: var(--shadow-card);
  transition: transform 0.25s ease, border-color 0.25s ease;
  min-width: 0;
}

.pricing-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-glow);
}

.pricing-card.featured {
  border-color: var(--cyan);
  background: linear-gradient(180deg, rgba(11, 31, 64, 0.96) 0%, rgba(9, 20, 44, 0.95) 100%);
  box-shadow: 0 24px 55px rgba(0, 242, 254, 0.16);
}

.plan-badge {
  position: absolute;
  top: -13px;
  left: 50%;
  transform: translateX(-50%);
  padding: 0.28rem 0.95rem;
  border-radius: 999px;
  background: var(--grad-brand);
  color: #031122;
  font-size: 0.78rem;
  font-weight: 800;
  white-space: nowrap;
}

.plan-name {
  margin: 0 0 0.35rem;
  font-size: 1.32rem;
  font-weight: 800;
}

.plan-sub {
  margin: 0 0 1.25rem;
  color: var(--text-muted);
  font-size: 0.88rem;
  min-height: 2.6em;
}

.price-block {
  padding: 1rem 0 1.25rem;
  margin-bottom: 1.25rem;
  border-top: 1px solid rgba(74, 158, 255, 0.14);
  border-bottom: 1px solid rgba(74, 158, 255, 0.14);
}

.price-main {
  display: flex;
  align-items: baseline;
  gap: 0.25rem;
}

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

.amount {
  font-size: 2.55rem;
  font-weight: 900;
  line-height: 1;
  color: var(--text-main);
  letter-spacing: -0.02em;
}

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

.price-note {
  margin: 0.45rem 0 0;
  font-size: 0.82rem;
  color: var(--emerald);
  font-weight: 600;
}

.plan-specs {
  list-style: none;
  margin: 0 0 1.75rem;
  padding: 0;
  display: grid;
  gap: 0.7rem;
}

.plan-specs li {
  display: flex;
  align-items: flex-start;
  gap: 0.55rem;
  font-size: 0.92rem;
  color: var(--text-muted);
}

.plan-specs li::before {
  content: "✓";
  color: var(--cyan);
  font-weight: 800;
  flex-shrink: 0;
}

.plan-specs strong {
  color: var(--text-main);
}

.plan-cta {
  margin-top: auto;
}

.mobile-scroll-hint {
  display: none;
  margin-top: 0.85rem;
  font-size: 0.82rem;
  color: var(--sky);
}

@media (max-width: 860px) {
  .pricing-row {
    grid-template-columns: repeat(3, minmax(268px, 1fr));
    overflow-x: auto;
    scroll-snap-type: x mandatory;
    padding: 1rem 0.25rem 0.9rem;
    gap: 1rem;
  }
  .pricing-card {
    scroll-snap-align: start;
  }
  .mobile-scroll-hint {
    display: block;
  }
}

/* Comparison Table for GEO & Quick Scan */
.table-wrap {
  margin-top: 2.5rem;
  width: 100%;
  overflow-x: auto;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-subtle);
  background: var(--surface-strong);
}

.spec-table {
  width: 100%;
  border-collapse: collapse;
  min-width: 680px;
  font-size: 0.92rem;
}

.spec-table th,
.spec-table td {
  padding: 0.95rem 1.15rem;
  text-align: left;
  border-bottom: 1px solid rgba(74, 158, 255, 0.12);
}

.spec-table th {
  background: rgba(0, 242, 254, 0.08);
  color: var(--cyan);
  font-weight: 700;
}

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

/* =========================================================
   Articles Grid & Cross-Links
   ========================================================= */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1.35rem;
}

.article-card {
  display: flex;
  flex-direction: column;
  background: var(--surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  box-shadow: var(--shadow-card);
  transition: transform 0.25s ease, border-color 0.25s ease;
}

.article-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-glow);
}

.article-tag-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin-bottom: 0.85rem;
}

.tag-pill {
  font-size: 0.74rem;
  font-weight: 600;
  padding: 0.2rem 0.6rem;
  border-radius: 6px;
  background: rgba(56, 189, 248, 0.12);
  color: var(--sky);
}

.article-card h3 {
  margin: 0 0 0.65rem;
  font-size: 1.08rem;
  line-height: 1.42;
}

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

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

.article-card p {
  margin: 0 0 1.2rem;
  color: var(--text-muted);
  font-size: 0.91rem;
  flex-grow: 1;
}

.article-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.83rem;
  color: var(--text-dim);
  padding-top: 0.85rem;
  border-top: 1px solid rgba(74, 158, 255, 0.12);
}

.article-meta a {
  font-weight: 700;
  color: var(--cyan);
}

@media (max-width: 920px) {
  .articles-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 600px) {
  .articles-grid {
    grid-template-columns: 1fr;
  }
}

/* =========================================================
   External Authority Links
   ========================================================= */
.ext-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1.15rem;
}

.ext-card {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
  padding: 1.25rem;
  border-radius: var(--radius-md);
  background: var(--surface);
  border: 1px solid var(--border-subtle);
  transition: border-color 0.2s ease, transform 0.2s ease;
}

.ext-card:hover {
  border-color: var(--border-glow);
  transform: translateY(-3px);
}

.ext-card strong {
  color: var(--text-main);
  font-size: 1rem;
}

.ext-card span {
  color: var(--text-muted);
  font-size: 0.86rem;
}

.ext-url {
  font-family: var(--font-mono);
  font-size: 0.76rem;
  color: var(--cyan);
  margin-top: auto;
  word-break: break-all;
}

@media (max-width: 860px) {
  .ext-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 560px) {
  .ext-grid {
    grid-template-columns: 1fr;
  }
}

/* =========================================================
   User Reviews Section
   ========================================================= */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1.35rem;
}

.review-card {
  background: var(--surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.review-stars {
  color: var(--amber);
  font-size: 0.95rem;
  letter-spacing: 0.08em;
}

.review-text {
  margin: 0;
  color: var(--text-main);
  font-size: 0.94rem;
  line-height: 1.68;
  flex-grow: 1;
}

.reviewer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 0.75rem;
  border-top: 1px solid rgba(74, 158, 255, 0.12);
  font-size: 0.83rem;
}

.reviewer strong {
  color: var(--cyan);
}

.reviewer span {
  color: var(--text-dim);
}

@media (max-width: 900px) {
  .reviews-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 600px) {
  .reviews-grid {
    grid-template-columns: 1fr;
  }
}

/* =========================================================
   Pure-CSS Native FAQ Accordion (<details> / <summary>)
   ========================================================= */
.faq-list {
  max-width: 880px;
  margin: 0 auto;
  display: grid;
  gap: 0.9rem;
}

.faq-item {
  background: var(--surface-strong);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: border-color 0.2s ease;
}

.faq-item[open] {
  border-color: var(--border-glow);
}

.faq-item summary {
  list-style: none;
  cursor: pointer;
  padding: 1.15rem 1.4rem;
  font-weight: 700;
  font-size: 1.02rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  color: var(--text-main);
}

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

.faq-item summary::after {
  content: "+";
  font-size: 1.35rem;
  font-weight: 400;
  color: var(--cyan);
  transition: transform 0.2s ease;
  flex-shrink: 0;
}

.faq-item[open] summary::after {
  transform: rotate(45deg);
}

.faq-answer {
  padding: 0 1.4rem 1.25rem;
  color: var(--text-muted);
  font-size: 0.95rem;
  border-top: 1px solid rgba(74, 158, 255, 0.1);
  padding-top: 0.9rem;
}

/* =========================================================
   Bottom CTA Banner & Footer
   ========================================================= */
.cta-banner {
  background: linear-gradient(135deg, rgba(0, 242, 254, 0.14), rgba(91, 115, 255, 0.2));
  border: 1px solid rgba(0, 242, 254, 0.35);
  border-radius: var(--radius-lg);
  padding: 2.8rem 2rem;
  text-align: center;
  box-shadow: var(--shadow-glow);
}

.cta-banner h2 {
  margin: 0 0 0.75rem;
  font-size: clamp(1.5rem, 3vw, 2.15rem);
}

.cta-banner p {
  margin: 0 auto 1.6rem;
  max-width: 640px;
  color: var(--text-muted);
}

.site-footer {
  border-top: 1px solid rgba(74, 158, 255, 0.14);
  background: rgba(4, 9, 20, 0.85);
  padding: 3.2rem 0 2rem;
  margin-top: 2rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1fr;
  gap: 2rem;
  margin-bottom: 2.2rem;
}

.footer-col h4 {
  margin: 0 0 0.95rem;
  font-size: 0.98rem;
  color: var(--text-main);
}

.footer-links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.55rem;
  font-size: 0.89rem;
}

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

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

.footer-bottom {
  padding-top: 1.4rem;
  border-top: 1px solid rgba(74, 158, 255, 0.1);
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  justify-content: space-between;
  font-size: 0.83rem;
  color: var(--text-dim);
}

@media (max-width: 860px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 540px) {
  .footer-grid {
    grid-template-columns: 1fr;
  }
}

/* =========================================================
   Article Detail Page Styles
   ========================================================= */
.article-shell {
  padding: 2.8rem 0 4.5rem;
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.45rem;
  font-size: 0.87rem;
  color: var(--text-dim);
  margin-bottom: 1.5rem;
}

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

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

.article-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 310px;
  gap: 2.2rem;
  align-items: start;
}

.article-main {
  background: var(--surface-strong);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 2.2rem 2.3rem;
  box-shadow: var(--shadow-card);
}

.article-main h1 {
  margin: 0 0 1rem;
  font-size: clamp(1.55rem, 2.8vw, 2.15rem);
  line-height: 1.32;
}

.article-byline {
  display: flex;
  flex-wrap: wrap;
  gap: 0.9rem;
  padding-bottom: 1.25rem;
  margin-bottom: 1.65rem;
  border-bottom: 1px solid rgba(74, 158, 255, 0.14);
  font-size: 0.85rem;
  color: var(--text-muted);
}

.geo-summary-box {
  padding: 1.15rem 1.3rem;
  margin-bottom: 1.75rem;
  border-radius: var(--radius-md);
  background: rgba(0, 242, 254, 0.07);
  border-left: 3px solid var(--cyan);
  font-size: 0.94rem;
}

.geo-summary-box strong {
  color: var(--cyan);
}

.article-body h2 {
  margin: 1.9rem 0 0.85rem;
  font-size: 1.3rem;
  color: var(--text-main);
  padding-bottom: 0.35rem;
  border-bottom: 1px solid rgba(74, 158, 255, 0.12);
}

.article-body h3 {
  margin: 1.35rem 0 0.6rem;
  font-size: 1.08rem;
  color: var(--sky);
}

.article-body p {
  margin: 0 0 1.05rem;
  color: #d6e3f7;
  line-height: 1.85;
  font-size: 1rem;
}

.article-body ul,
.article-body ol {
  margin: 0 0 1.15rem;
  padding-left: 1.35rem;
  color: #d6e3f7;
}

.article-body li {
  margin-bottom: 0.48rem;
}

.article-pager {
  margin-top: 2.2rem;
  padding-top: 1.4rem;
  border-top: 1px solid rgba(74, 158, 255, 0.16);
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.pager-link {
  padding: 1rem 1.15rem;
  border-radius: var(--radius-md);
  background: rgba(7, 16, 36, 0.85);
  border: 1px solid var(--border-subtle);
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.pager-link:hover {
  border-color: var(--border-glow);
}

.pager-link span {
  font-size: 0.78rem;
  color: var(--text-dim);
}

.pager-link strong {
  font-size: 0.93rem;
  color: var(--text-main);
}

.article-sidebar {
  position: sticky;
  top: 94px;
  display: grid;
  gap: 1.25rem;
}

.sidebar-card {
  background: var(--surface-strong);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.35rem;
}

.sidebar-card h3 {
  margin: 0 0 0.85rem;
  font-size: 1.02rem;
  color: var(--cyan);
}

.sidebar-links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.6rem;
  font-size: 0.89rem;
}

.sidebar-links a {
  color: var(--text-muted);
}

.sidebar-links a:hover {
  color: var(--cyan);
}

@media (max-width: 960px) {
  .article-layout {
    grid-template-columns: 1fr;
  }
  .article-main {
    padding: 1.55rem 1.35rem;
  }
  .article-sidebar {
    position: static;
  }
}

@media (max-width: 600px) {
  .article-pager {
    grid-template-columns: 1fr;
  }
}