/* ==========================================================================
   Tanz Cloud 飞毯加速 (tanzcloud.mom) — Pure Native CSS Design System
   Zero JS Runtime | Zero External Frameworks | GPU-Accelerated Dynamic Backdrop
   ========================================================================== */

:root {
  --bg-canvas: #07060d;
  --bg-layer: rgba(15, 13, 28, 0.78);
  --bg-layer-solid: #110f20;
  --bg-card-hover: rgba(24, 20, 44, 0.9);
  --border-hairline: rgba(255, 255, 255, 0.09);
  --border-cyan: rgba(0, 224, 255, 0.42);
  --border-flame: rgba(255, 123, 41, 0.52);

  --ink-primary: #f8fafc;
  --ink-secondary: #cbd5e1;
  --ink-muted: #94a3b8;

  --cyan: #00e0ff;
  --flame: #ff7b29;
  --magenta: #ff2e88;
  --emerald: #34d399;
  --amber: #fbbf24;

  --grad-aurora: linear-gradient(125deg, #00e0ff 0%, #ff7b29 52%, #ff2e88 100%);
  --grad-cta-hot: linear-gradient(135deg, #ff7b29 0%, #ff2e88 100%);
  --grad-cta-cool: linear-gradient(135deg, #00c4ff 0%, #2563eb 100%);

  --radius-sm: 10px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-pill: 999px;

  --shadow-card: 0 22px 50px -20px rgba(0, 0, 0, 0.82);
  --shadow-flame: 0 12px 34px -8px rgba(255, 123, 41, 0.36);
  --shadow-cyan: 0 12px 32px -10px rgba(0, 224, 255, 0.28);

  --container: 1200px;
  --font-sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "HarmonyOS Sans SC",
    "Microsoft YaHei", "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  background-color: var(--bg-canvas);
  color: var(--ink-primary);
  font-family: var(--font-sans);
  line-height: 1.7;
  overflow-x: hidden;
  position: relative;
}

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

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

/* ==========================================================================
   Dynamic Pure-CSS Animated Background (Zero JS)
   ========================================================================== */
.ambient-stage {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  overflow: hidden;
  background: radial-gradient(circle at 18% 15%, rgba(255, 123, 41, 0.12), transparent 44%),
    radial-gradient(circle at 82% 20%, rgba(0, 224, 255, 0.12), transparent 42%),
    radial-gradient(circle at 50% 88%, rgba(255, 46, 136, 0.1), transparent 48%),
    var(--bg-canvas);
}

.aurora-ribbon {
  position: absolute;
  border-radius: 50%;
  filter: blur(78px);
  will-change: transform, opacity;
  opacity: 0.42;
}

.ribbon-a {
  width: 680px;
  height: 420px;
  top: -120px;
  left: -100px;
  background: radial-gradient(circle, rgba(255, 123, 41, 0.55) 0%, rgba(255, 46, 136, 0.25) 55%, transparent 75%);
  animation: ribbonDriftA 20s ease-in-out infinite alternate;
}

.ribbon-b {
  width: 720px;
  height: 460px;
  top: 12%;
  right: -160px;
  background: radial-gradient(circle, rgba(0, 224, 255, 0.48) 0%, rgba(56, 189, 248, 0.18) 55%, transparent 75%);
  animation: ribbonDriftB 24s ease-in-out infinite alternate;
}

.ribbon-c {
  width: 620px;
  height: 380px;
  bottom: -110px;
  left: 26%;
  background: radial-gradient(circle, rgba(139, 92, 246, 0.42) 0%, rgba(255, 46, 136, 0.2) 55%, transparent 75%);
  animation: ribbonDriftC 26s ease-in-out infinite alternate;
}

.star-layer {
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(1.5px 1.5px at 14% 22%, rgba(255, 255, 255, 0.7), transparent),
    radial-gradient(2px 2px at 28% 68%, rgba(0, 224, 255, 0.8), transparent),
    radial-gradient(1.5px 1.5px at 44% 16%, rgba(255, 123, 41, 0.8), transparent),
    radial-gradient(1.5px 1.5px at 63% 44%, rgba(255, 255, 255, 0.65), transparent),
    radial-gradient(2px 2px at 78% 26%, rgba(255, 46, 136, 0.7), transparent),
    radial-gradient(1.5px 1.5px at 88% 74%, rgba(0, 224, 255, 0.75), transparent),
    radial-gradient(1.5px 1.5px at 9% 84%, rgba(255, 255, 255, 0.55), transparent),
    radial-gradient(2px 2px at 54% 86%, rgba(255, 123, 41, 0.65), transparent);
  animation: starBreath 6s ease-in-out infinite alternate;
}

/* ==========================================================================
   Dynamic 3D Spinning Earth & Marked Global Nodes (Pure CSS + SVG, Zero JS)
   ========================================================================== */
.earth-system {
  position: absolute;
  left: 50%;
  top: 52%;
  transform: translate(-50%, -50%);
  width: min(94vw, 790px);
  height: min(94vw, 790px);
  opacity: 0.82;
}

.earth-aura {
  position: absolute;
  inset: -12%;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(0, 224, 255, 0.24) 36%, rgba(255, 123, 41, 0.14) 56%, transparent 74%);
  filter: blur(26px);
  animation: auraPulse 8s ease-in-out infinite alternate;
}

.earth-sphere {
  position: relative;
  width: 100%;
  height: 100%;
  border-radius: 50%;
  overflow: hidden;
  background: radial-gradient(circle at 32% 28%, #16305f 0%, #0b1734 55%, #040712 100%);
  border: 1px solid rgba(0, 224, 255, 0.34);
  box-shadow:
    inset -72px -48px 125px rgba(2, 3, 10, 0.88),
    inset 36px 26px 86px rgba(0, 224, 255, 0.24),
    0 0 95px rgba(0, 224, 255, 0.2);
}

.earth-map-track {
  position: absolute;
  left: 0;
  top: 10%;
  width: 300%;
  height: 80%;
  max-width: none;
  opacity: 0.96;
  will-change: transform;
  animation: earthSpin 52s linear infinite;
}

.earth-graticule {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 2;
}

.earth-orbit {
  position: absolute;
  left: 50%;
  top: 50%;
  border-radius: 50%;
  border: 1px dashed rgba(0, 224, 255, 0.25);
  pointer-events: none;
}

.orbit-1 {
  width: 118%;
  height: 118%;
  transform: translate(-50%, -50%) rotateX(70deg) rotateZ(-16deg);
  animation: orbitSpinA 24s linear infinite;
}

.orbit-2 {
  width: 130%;
  height: 130%;
  border-color: rgba(255, 123, 41, 0.24);
  transform: translate(-50%, -50%) rotateX(68deg) rotateZ(22deg);
  animation: orbitSpinB 32s linear infinite reverse;
}

.sat-dot {
  position: absolute;
  top: -5px;
  left: 50%;
  width: 10px;
  height: 10px;
  margin-left: -5px;
  border-radius: 50%;
  background: var(--cyan);
  box-shadow: 0 0 14px var(--cyan), 0 0 28px rgba(0, 224, 255, 0.8);
}

.sat-dot.hot {
  background: var(--flame);
  box-shadow: 0 0 14px var(--flame), 0 0 28px rgba(255, 123, 41, 0.85);
}

@keyframes earthSpin {
  0% { transform: translate3d(-11.3333%, 0, 0); }
  100% { transform: translate3d(-44.6667%, 0, 0); }
}

@keyframes auraPulse {
  0% { opacity: 0.72; transform: scale(0.98); }
  100% { opacity: 1; transform: scale(1.03); }
}

@keyframes orbitSpinA {
  0% { transform: translate(-50%, -50%) rotateX(70deg) rotateZ(-16deg) rotate(0deg); }
  100% { transform: translate(-50%, -50%) rotateX(70deg) rotateZ(-16deg) rotate(360deg); }
}

@keyframes orbitSpinB {
  0% { transform: translate(-50%, -50%) rotateX(68deg) rotateZ(22deg) rotate(0deg); }
  100% { transform: translate(-50%, -50%) rotateX(68deg) rotateZ(22deg) rotate(360deg); }
}

@keyframes ribbonDriftA {
  0% { transform: translate3d(0, 0, 0) scale(1) rotate(0deg); }
  100% { transform: translate3d(90px, 60px, 0) scale(1.12) rotate(12deg); }
}

@keyframes ribbonDriftB {
  0% { transform: translate3d(0, 0, 0) scale(1) rotate(0deg); }
  100% { transform: translate3d(-110px, 85px, 0) scale(1.1) rotate(-14deg); }
}

@keyframes ribbonDriftC {
  0% { transform: translate3d(0, 0, 0) scale(1); }
  100% { transform: translate3d(-70px, -65px, 0) scale(1.14); }
}

@keyframes starBreath {
  0% { opacity: 0.45; }
  100% { opacity: 0.9; }
}

@media (prefers-reduced-motion: reduce) {
  .aurora-ribbon,
  .star-layer,
  .earth-aura,
  .earth-map-track,
  .earth-orbit {
    animation: none !important;
  }
}

/* ==========================================================================
   Layout Utilities & Typography
   ========================================================================== */
.site-shell {
  position: relative;
  z-index: 1;
}

.container {
  width: min(var(--container), calc(100% - 32px));
  margin-inline: auto;
}

.section {
  padding: 72px 0;
}

.section-tight {
  padding: 48px 0;
}

.section-head {
  text-align: center;
  max-width: 760px;
  margin: 0 auto 44px;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  border-radius: var(--radius-pill);
  background: rgba(0, 224, 255, 0.08);
  border: 1px solid rgba(0, 224, 255, 0.28);
  color: var(--cyan);
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  margin-bottom: 14px;
}

.eyebrow-flame {
  background: rgba(255, 123, 41, 0.12);
  border-color: rgba(255, 123, 41, 0.36);
  color: #ffb07a;
}

.section-title {
  margin: 0 0 12px;
  font-size: clamp(1.7rem, 3vw, 2.35rem);
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: -0.02em;
}

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

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

.tnum {
  font-variant-numeric: tabular-nums;
}

/* ==========================================================================
   Sticky Top Bar with Top-Left Logo
   ========================================================================== */
.topbar {
  position: sticky;
  top: 0;
  z-index: 60;
  background: rgba(7, 6, 13, 0.82);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  border-bottom: 1px solid var(--border-hairline);
}

.topbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  min-height: 74px;
}

.brand-link {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
}

.brand-avatar {
  width: 46px;
  height: 46px;
  border-radius: 50%;
  padding: 2px;
  background: var(--grad-aurora);
  box-shadow: 0 0 22px rgba(255, 123, 41, 0.4);
  flex-shrink: 0;
}

.brand-avatar img {
  width: 100%;
  height: 100%;
  border-radius: 50%;
  object-fit: cover;
  background: #0d0a19;
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}

.brand-name {
  font-size: 1.08rem;
  font-weight: 800;
  letter-spacing: -0.01em;
}

.brand-sub {
  font-size: 0.76rem;
  color: var(--ink-muted);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 22px;
  font-size: 0.93rem;
  color: var(--ink-secondary);
}

.nav-links a {
  padding: 6px 2px;
  transition: color 0.2s ease;
  white-space: nowrap;
}

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

.nav-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

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

.mobile-nav summary {
  list-style: none;
  cursor: pointer;
  padding: 8px 14px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--border-hairline);
  background: rgba(255, 255, 255, 0.04);
  font-size: 0.88rem;
  font-weight: 600;
}

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

.mobile-drawer {
  position: absolute;
  right: 0;
  top: calc(100% + 10px);
  width: 220px;
  padding: 12px;
  border-radius: var(--radius-md);
  background: #120f24;
  border: 1px solid var(--border-hairline);
  box-shadow: var(--shadow-card);
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.mobile-drawer a {
  padding: 8px 10px;
  border-radius: 8px;
  font-size: 0.92rem;
  color: var(--ink-secondary);
}

.mobile-drawer a:hover {
  background: rgba(255, 255, 255, 0.06);
  color: var(--cyan);
}

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

/* ==========================================================================
   Buttons (Zero-JS Shimmer & Hover Lift)
   ========================================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 22px;
  border-radius: var(--radius-pill);
  font-weight: 700;
  font-size: 0.95rem;
  border: 1px solid transparent;
  transition: transform 0.22s ease, box-shadow 0.22s ease, border-color 0.22s ease, background 0.22s ease;
  cursor: pointer;
  white-space: nowrap;
}

.btn:hover {
  transform: translateY(-2px);
}

.btn-flame {
  background: var(--grad-cta-hot);
  color: #ffffff;
  box-shadow: var(--shadow-flame);
}

.btn-flame:hover {
  box-shadow: 0 16px 38px -8px rgba(255, 46, 136, 0.5);
}

.btn-cyan {
  background: var(--grad-cta-cool);
  color: #ffffff;
  box-shadow: var(--shadow-cyan);
}

.btn-ghost {
  background: rgba(255, 255, 255, 0.04);
  border-color: var(--border-hairline);
  color: var(--ink-primary);
}

.btn-ghost:hover {
  border-color: var(--border-cyan);
  background: rgba(0, 224, 255, 0.08);
}

.btn-sm {
  padding: 9px 16px;
  font-size: 0.86rem;
}

.btn-block {
  width: 100%;
}

/* ==========================================================================
   Hero Centered Section
   ========================================================================== */
.hero {
  padding: 68px 0 46px;
}

.hero-single {
  max-width: 920px;
  margin-inline: auto;
  text-align: center;
  padding: 28px 20px;
  border-radius: 32px;
  background: radial-gradient(ellipse at 50% 42%, rgba(7, 6, 13, 0.72) 0%, rgba(7, 6, 13, 0.34) 56%, transparent 82%);
}

.status-pill {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 7px 14px;
  border-radius: var(--radius-pill);
  background: rgba(10, 22, 24, 0.76);
  backdrop-filter: blur(8px);
  border: 1px solid rgba(52, 211, 153, 0.4);
  color: #a7f3d0;
  font-size: 0.84rem;
  font-weight: 600;
  margin-bottom: 18px;
}

.pulse-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--emerald);
  box-shadow: 0 0 0 4px rgba(52, 211, 153, 0.25);
}

.hero-title {
  margin: 0 0 18px;
  font-size: clamp(2.1rem, 4.4vw, 3.25rem);
  font-weight: 900;
  line-height: 1.18;
  letter-spacing: -0.025em;
  text-shadow: 0 4px 26px rgba(7, 6, 13, 0.95);
}

.hero-lead {
  margin: 0 auto 28px;
  color: var(--ink-primary);
  font-size: 1.07rem;
  max-width: 68ch;
  text-shadow: 0 2px 18px rgba(7, 6, 13, 0.96);
}

.hero-cta-row {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 14px;
  margin-bottom: 34px;
}

.hero-metrics {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
}

.metric-box {
  padding: 16px 14px;
  border-radius: var(--radius-md);
  background: rgba(12, 11, 24, 0.8);
  backdrop-filter: blur(12px);
  border: 1px solid var(--border-hairline);
  text-align: center;
}

.metric-val {
  display: block;
  font-size: 1.28rem;
  font-weight: 800;
  color: var(--cyan);
  line-height: 1.2;
}

.metric-label {
  display: block;
  font-size: 0.8rem;
  color: var(--ink-muted);
  margin-top: 4px;
}

@media (max-width: 960px) {
  .hero-metrics {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

/* ==========================================================================
   Pricing Section — Strict Single Horizontal Row ("所有价格要同排")
   Pure CSS Radio Billing Toggle (Zero JS)
   ========================================================================== */
.pricing-stage {
  position: relative;
}

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

.billing-switch-wrap {
  display: flex;
  justify-content: center;
  margin-bottom: 30px;
}

.billing-switch {
  display: inline-flex;
  padding: 5px;
  border-radius: var(--radius-pill);
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--border-hairline);
  gap: 4px;
}

.billing-label {
  cursor: pointer;
  padding: 8px 20px;
  border-radius: var(--radius-pill);
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--ink-secondary);
  transition: background 0.2s ease, color 0.2s ease;
}

.save-tag {
  font-size: 0.72rem;
  padding: 2px 7px;
  border-radius: var(--radius-pill);
  background: rgba(255, 123, 41, 0.2);
  color: #ffb07a;
  margin-left: 6px;
}

#bill-monthly:checked ~ .billing-switch-wrap label[for="bill-monthly"],
#bill-annual:checked ~ .billing-switch-wrap label[for="bill-annual"] {
  background: var(--grad-cta-hot);
  color: #ffffff;
}

.price-annual {
  display: none;
}

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

#bill-annual:checked ~ .pricing-grid .price-annual {
  display: inline-flex;
}

/* All 3 plans strictly in ONE horizontal row */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 22px;
  align-items: stretch;
}

@media (max-width: 820px) {
  .pricing-grid {
    grid-template-columns: repeat(3, minmax(268px, 1fr));
    overflow-x: auto;
    scroll-snap-type: x mandatory;
    padding-bottom: 14px;
  }
  .pricing-card {
    scroll-snap-align: start;
  }
}

.pricing-card {
  position: relative;
  display: flex;
  flex-direction: column;
  padding: 28px 24px;
  border-radius: var(--radius-lg);
  background: var(--bg-layer);
  border: 1px solid var(--border-hairline);
  box-shadow: var(--shadow-card);
  backdrop-filter: blur(14px);
  transition: transform 0.24s ease, border-color 0.24s ease;
}

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

.pricing-card.featured {
  background: linear-gradient(180deg, rgba(255, 123, 41, 0.11) 0%, rgba(18, 15, 32, 0.92) 42%);
  border-color: var(--border-flame);
  box-shadow: 0 24px 56px -18px rgba(255, 123, 41, 0.34);
}

.plan-badge {
  position: absolute;
  top: -13px;
  right: 22px;
  padding: 4px 12px;
  border-radius: var(--radius-pill);
  background: var(--grad-cta-hot);
  color: #ffffff;
  font-size: 0.76rem;
  font-weight: 800;
  letter-spacing: 0.03em;
}

.plan-tier {
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--cyan);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.pricing-card.featured .plan-tier {
  color: #ffb07a;
}

.plan-name {
  margin: 4px 0 8px;
  font-size: 1.45rem;
  font-weight: 800;
}

.plan-desc {
  margin: 0 0 18px;
  color: var(--ink-muted);
  font-size: 0.9rem;
  min-height: 44px;
}

.plan-price-row {
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  margin-bottom: 6px;
}

.currency {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--ink-primary);
}

.amount {
  font-size: 2.75rem;
  font-weight: 900;
  line-height: 1;
  letter-spacing: -0.03em;
}

.period {
  color: var(--ink-muted);
  font-size: 0.92rem;
}

.plan-alt-price {
  font-size: 0.84rem;
  color: #cbd5e1;
  margin-bottom: 18px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border-hairline);
}

.plan-specs {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
  margin-bottom: 18px;
}

.spec-pill {
  padding: 10px;
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.035);
  border: 1px solid rgba(255, 255, 255, 0.06);
  text-align: center;
}

.spec-pill strong {
  display: block;
  font-size: 1.02rem;
  color: var(--ink-primary);
}

.spec-pill span {
  font-size: 0.76rem;
  color: var(--ink-muted);
}

.plan-features {
  list-style: none;
  margin: 0 0 24px;
  padding: 0;
  display: grid;
  gap: 10px;
  flex: 1;
  font-size: 0.92rem;
  color: var(--ink-secondary);
}

.plan-features li {
  display: flex;
  align-items: flex-start;
  gap: 8px;
}

.check-icon {
  flex-shrink: 0;
  width: 18px;
  height: 18px;
  margin-top: 3px;
  color: var(--emerald);
}

/* Comparison Table */
.table-wrap {
  margin-top: 32px;
  overflow-x: auto;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-hairline);
  background: var(--bg-layer);
}

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

.compare-table th,
.compare-table td {
  padding: 14px 16px;
  text-align: left;
  border-bottom: 1px solid var(--border-hairline);
}

.compare-table th {
  background: rgba(255, 255, 255, 0.03);
  color: var(--ink-primary);
  font-weight: 700;
}

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

.pricing-footnote {
  margin-top: 16px;
  text-align: center;
  color: var(--ink-muted);
  font-size: 0.86rem;
}

/* ==========================================================================
   Feature Pillars, Node Architecture & External Resources
   ========================================================================== */
.cards-4 {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 18px;
}

.cards-3 {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 20px;
}

.cards-2 {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px;
}

@media (max-width: 1024px) {
  .cards-4 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 720px) {
  .cards-4,
  .cards-3,
  .cards-2 {
    grid-template-columns: 1fr;
  }
}

.glass-card {
  padding: 24px;
  border-radius: var(--radius-md);
  background: var(--bg-layer);
  border: 1px solid var(--border-hairline);
  box-shadow: var(--shadow-card);
  transition: border-color 0.2s ease, transform 0.2s ease;
}

.glass-card:hover {
  border-color: rgba(0, 224, 255, 0.34);
  transform: translateY(-3px);
}

.icon-badge {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  display: grid;
  place-items: center;
  background: rgba(0, 224, 255, 0.1);
  border: 1px solid rgba(0, 224, 255, 0.25);
  color: var(--cyan);
  margin-bottom: 14px;
}

.icon-badge.flame {
  background: rgba(255, 123, 41, 0.12);
  border-color: rgba(255, 123, 41, 0.32);
  color: var(--flame);
}

.glass-card h3 {
  margin: 0 0 8px;
  font-size: 1.1rem;
  font-weight: 700;
}

.glass-card p {
  margin: 0;
  color: var(--ink-secondary);
  font-size: 0.92rem;
}

/* Node Topology Frame */
.topology-frame {
  padding: 18px;
  border-radius: var(--radius-lg);
  background: var(--bg-layer);
  border: 1px solid var(--border-hairline);
  margin-bottom: 26px;
}

.topology-frame img {
  width: 100%;
  height: auto;
  border-radius: 14px;
}

/* External Links Ecosystem Cards */
.ext-card {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 12px;
}

.ext-link-cta {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--cyan);
}

.ext-link-cta:hover {
  text-decoration: underline;
}

/* ==========================================================================
   Articles Knowledge Base Cards
   ========================================================================== */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px;
}

@media (max-width: 820px) {
  .articles-grid {
    grid-template-columns: 1fr;
  }
}

.article-card {
  display: flex;
  flex-direction: column;
  padding: 24px;
  border-radius: var(--radius-md);
  background: var(--bg-layer);
  border: 1px solid var(--border-hairline);
  transition: transform 0.2s ease, border-color 0.2s ease;
}

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

.tag-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 12px;
}

.tag-pill {
  font-size: 0.74rem;
  padding: 3px 9px;
  border-radius: var(--radius-pill);
  background: rgba(255, 123, 41, 0.11);
  border: 1px solid rgba(255, 123, 41, 0.28);
  color: #ffc59e;
  font-weight: 600;
}

.article-card h3 {
  margin: 0 0 10px;
  font-size: 1.14rem;
  line-height: 1.4;
}

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

.article-card p {
  margin: 0 0 16px;
  color: var(--ink-secondary);
  font-size: 0.92rem;
  flex: 1;
}

.article-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.82rem;
  color: var(--ink-muted);
  padding-top: 12px;
  border-top: 1px solid var(--border-hairline);
}

.read-more {
  color: var(--cyan);
  font-weight: 700;
}

/* ==========================================================================
   User Reviews Section (Bottom)
   ========================================================================== */
.rating-summary {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 18px;
  padding: 18px 24px;
  border-radius: var(--radius-md);
  background: rgba(255, 123, 41, 0.08);
  border: 1px solid rgba(255, 123, 41, 0.3);
  max-width: 720px;
  margin: 0 auto 30px;
}

.rating-score {
  font-size: 2rem;
  font-weight: 900;
  color: var(--amber);
  line-height: 1;
}

.stars {
  color: var(--amber);
  letter-spacing: 2px;
  font-size: 1.05rem;
}

.review-card {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.review-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
}

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

.avatar-circle {
  width: 38px;
  height: 38px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  font-weight: 800;
  font-size: 0.9rem;
  background: var(--grad-aurora);
  color: #07060d;
}

.reviewer-name {
  font-weight: 700;
  font-size: 0.95rem;
}

.reviewer-role {
  font-size: 0.78rem;
  color: var(--ink-muted);
}

.review-plan {
  font-size: 0.74rem;
  padding: 3px 9px;
  border-radius: var(--radius-pill);
  background: rgba(0, 224, 255, 0.1);
  color: var(--cyan);
}

/* ==========================================================================
   Pure-HTML Interactive FAQ Accordion
   ========================================================================== */
.faq-list {
  max-width: 900px;
  margin-inline: auto;
  display: grid;
  gap: 12px;
}

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

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

.faq-item summary {
  list-style: none;
  cursor: pointer;
  padding: 18px 22px;
  font-weight: 700;
  font-size: 1rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

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

.faq-item summary::after {
  content: "+";
  font-size: 1.3rem;
  color: var(--cyan);
  line-height: 1;
  transition: transform 0.2s ease;
}

.faq-item[open] summary::after {
  content: "−";
  color: var(--flame);
}

.faq-body {
  padding: 0 22px 18px;
  color: var(--ink-secondary);
  font-size: 0.94rem;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  padding-top: 14px;
}

/* ==========================================================================
   CTA Banner & Footer
   ========================================================================== */
.cta-banner {
  padding: 42px 32px;
  border-radius: var(--radius-lg);
  background: linear-gradient(135deg, rgba(255, 123, 41, 0.16), rgba(0, 224, 255, 0.11));
  border: 1px solid rgba(255, 123, 41, 0.36);
  text-align: center;
  box-shadow: var(--shadow-card);
}

.cta-banner h2 {
  margin: 0 0 12px;
  font-size: clamp(1.5rem, 2.8vw, 2.1rem);
}

.cta-banner p {
  margin: 0 auto 24px;
  max-width: 640px;
  color: var(--ink-secondary);
}

.site-footer {
  margin-top: 40px;
  padding: 52px 0 32px;
  border-top: 1px solid var(--border-hairline);
  background: rgba(5, 4, 10, 0.85);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1fr;
  gap: 28px;
  margin-bottom: 34px;
}

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

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

.footer-col h4 {
  margin: 0 0 12px;
  font-size: 0.96rem;
  color: var(--ink-primary);
}

.footer-links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 8px;
  font-size: 0.88rem;
  color: var(--ink-muted);
}

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

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 12px;
  padding-top: 22px;
  border-top: 1px solid var(--border-hairline);
  font-size: 0.82rem;
  color: var(--ink-muted);
}

/* Utility Page Prose (sitemap.html, privacy.html, terms.html) */
.page-card {
  padding: 34px;
  border-radius: var(--radius-lg);
  background: var(--bg-layer);
  border: 1px solid var(--border-hairline);
  box-shadow: var(--shadow-card);
}

.page-card h1 {
  margin-top: 0;
}

.inline-link {
  color: var(--cyan);
  text-decoration: underline;
  text-underline-offset: 3px;
}