/* ==========================================================================
   FastNode.lol - Pure Native CSS Design System (Zero JS / Instant Load)
   ========================================================================== */

:root {
  --bg-void: #050914;
  --bg-deep: #091022;
  --surface: rgba(10, 19, 40, 0.86);
  --surface-strong: rgba(14, 25, 52, 0.94);
  --surface-hover: rgba(18, 32, 64, 0.92);
  --border-subtle: rgba(148, 163, 184, 0.16);
  --border-glow: rgba(0, 229, 255, 0.42);

  --cyan: #00e5ff;
  --cyan-soft: rgba(0, 229, 255, 0.14);
  --blue: #3b82f6;
  --indigo: #6366f1;
  --emerald: #10b981;
  --emerald-soft: rgba(16, 185, 129, 0.15);
  --amber: #f59e0b;

  --text-main: #f1f5f9;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;

  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-pill: 999px;

  --shadow-card: 0 18px 42px -18px rgba(0, 0, 0, 0.72);
  --shadow-cyan: 0 12px 32px -10px rgba(0, 229, 255, 0.35);

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace;
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  background-color: var(--bg-void);
  overflow-x: clip;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  color: var(--text-main);
  background: transparent;
  line-height: 1.7;
  min-height: 100vh;
  overflow-x: clip;
  position: relative;
}

main, header, footer {
  position: relative;
  z-index: 1;
}

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

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

a:hover {
  color: #7df3ff;
}

:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
}

/* ==========================================================================
   Dynamic Animated Cyber-Node Background (Pure CSS, GPU-Composited)
   ========================================================================== */
.bg-stage {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  overflow: hidden;
  background:
    radial-gradient(1200px 700px at 15% -10%, rgba(0, 229, 255, 0.11), transparent 60%),
    radial-gradient(900px 600px at 90% 10%, rgba(99, 102, 241, 0.14), transparent 60%),
    linear-gradient(180deg, #050914 0%, #070e20 55%, #050914 100%);
}

.bg-grid {
  position: absolute;
  inset: -96px;
  background-image:
    radial-gradient(circle at 1px 1px, rgba(0, 229, 255, 0.24) 1.2px, transparent 0),
    linear-gradient(to right, rgba(59, 130, 246, 0.06) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(59, 130, 246, 0.06) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: radial-gradient(ellipse 85% 75% at 50% 35%, #000 30%, transparent 95%);
  -webkit-mask-image: radial-gradient(ellipse 85% 75% at 50% 35%, #000 30%, transparent 95%);
  animation: gridPan 22s linear infinite;
  will-change: transform;
}

.bg-aurora {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  opacity: 0.42;
  will-change: transform, opacity;
}

.bg-aurora-a {
  width: 540px;
  height: 540px;
  top: -120px;
  left: -80px;
  background: radial-gradient(circle, rgba(0, 229, 255, 0.42), rgba(59, 130, 246, 0.08) 70%, transparent);
  animation: orbDriftA 18s ease-in-out infinite alternate;
}

.bg-aurora-b {
  width: 620px;
  height: 620px;
  top: 25%;
  right: -180px;
  background: radial-gradient(circle, rgba(99, 102, 241, 0.38), rgba(0, 229, 255, 0.06) 72%, transparent);
  animation: orbDriftB 24s ease-in-out infinite alternate;
}

.bg-aurora-c {
  width: 480px;
  height: 480px;
  bottom: -140px;
  left: 32%;
  background: radial-gradient(circle, rgba(16, 185, 129, 0.24), rgba(59, 130, 246, 0.08) 70%, transparent);
  animation: orbDriftA 26s ease-in-out infinite alternate-reverse;
}

.bg-beam {
  position: absolute;
  background: linear-gradient(90deg, transparent, rgba(0, 229, 255, 0.55), transparent);
  height: 1.5px;
  width: 280px;
  opacity: 0;
  will-change: transform, opacity;
}

.bg-beam-1 {
  top: 18%;
  left: -300px;
  animation: beamSweepH 9s linear infinite;
}

.bg-beam-2 {
  top: 58%;
  left: -300px;
  width: 340px;
  background: linear-gradient(90deg, transparent, rgba(99, 102, 241, 0.55), transparent);
  animation: beamSweepH 13s linear 3.5s infinite;
}

.bg-beam-v {
  position: absolute;
  width: 1.5px;
  height: 240px;
  top: -260px;
  left: 72%;
  background: linear-gradient(180deg, transparent, rgba(0, 229, 255, 0.45), transparent);
  opacity: 0;
  animation: beamSweepV 11s linear 1.8s infinite;
}

@keyframes gridPan {
  0% { transform: translate3d(0, 0, 0); }
  100% { transform: translate3d(48px, 48px, 0); }
}

@keyframes orbDriftA {
  0% { transform: translate3d(0, 0, 0) scale(1); }
  50% { transform: translate3d(70px, 45px, 0) scale(1.08); }
  100% { transform: translate3d(-20px, 80px, 0) scale(0.96); }
}

@keyframes orbDriftB {
  0% { transform: translate3d(0, 0, 0) scale(1); }
  50% { transform: translate3d(-90px, -40px, 0) scale(1.1); }
  100% { transform: translate3d(-30px, 60px, 0) scale(0.95); }
}

@keyframes beamSweepH {
  0% { transform: translate3d(0, 0, 0); opacity: 0; }
  15% { opacity: 0.75; }
  85% { opacity: 0.55; }
  100% { transform: translate3d(calc(100vw + 640px), 0, 0); opacity: 0; }
}

@keyframes beamSweepV {
  0% { transform: translate3d(0, 0, 0); opacity: 0; }
  20% { opacity: 0.65; }
  80% { opacity: 0.45; }
  100% { transform: translate3d(0, calc(100vh + 520px), 0); opacity: 0; }
}

/* ==========================================================================
   Pure CSS Dynamic Lightning & Electric Discharge Layer
   ========================================================================== */
.bg-flash {
  position: absolute;
  inset: 0;
  z-index: 1;
  background:
    radial-gradient(580px 420px at 14% 20%, rgba(0, 229, 255, 0.28), transparent 70%),
    radial-gradient(600px 440px at 86% 24%, rgba(59, 130, 246, 0.26), transparent 70%),
    radial-gradient(520px 380px at 50% 80%, rgba(99, 102, 241, 0.22), transparent 72%);
  opacity: 0.15;
  animation: skyDischarge 4.8s ease-out infinite;
  will-change: opacity;
}

.bg-bolt {
  position: absolute;
  z-index: 2;
  overflow: visible;
  pointer-events: none;
  opacity: 0.4;
  will-change: opacity, transform;
}

.bg-bolt-1 {
  top: -2%;
  left: 0%;
  width: min(360px, 42vw);
  height: auto;
  animation: lightningStrikeA 5.2s ease-in-out -0.15s infinite;
}

.bg-bolt-2 {
  top: -1%;
  right: 0%;
  width: min(390px, 44vw);
  height: auto;
  animation: lightningStrikeB 6.4s ease-in-out -2.1s infinite;
}

.bg-bolt-3 {
  bottom: -2%;
  left: 28%;
  width: min(340px, 38vw);
  height: auto;
  animation: lightningStrikeC 7.4s ease-in-out -4.2s infinite;
}

.bg-bolt-4 {
  top: 38%;
  left: -1%;
  width: min(290px, 32vw);
  height: auto;
  animation: lightningStrikeB 6.8s ease-in-out -0.35s infinite;
}

.bolt-halo {
  fill: none;
  stroke: rgba(0, 212, 255, 0.34);
  stroke-width: 14;
  stroke-linecap: round;
  stroke-linejoin: round;
  filter: blur(5px);
}

.bg-bolt-2 .bolt-halo {
  stroke: rgba(59, 130, 246, 0.36);
}

.bg-bolt-3 .bolt-halo,
.bg-bolt-4 .bolt-halo {
  stroke: rgba(99, 102, 241, 0.32);
}

.bolt-mid {
  fill: none;
  stroke: #00e5ff;
  stroke-width: 3.6;
  stroke-linecap: round;
  stroke-linejoin: round;
  opacity: 0.85;
  filter: blur(1.2px);
}

.bg-bolt-2 .bolt-mid {
  stroke: #38bdf8;
}

.bolt-core {
  fill: none;
  stroke: #ffffff;
  stroke-width: 1.45;
  stroke-linecap: round;
  stroke-linejoin: round;
  filter: drop-shadow(0 0 4px #ffffff) drop-shadow(0 0 10px rgba(0, 229, 255, 0.95));
}

.bolt-branch {
  fill: none;
  stroke: rgba(125, 243, 255, 0.85);
  stroke-width: 1.15;
  stroke-linecap: round;
  stroke-linejoin: round;
  filter: drop-shadow(0 0 4px rgba(0, 229, 255, 0.8));
}

.bolt-twig {
  fill: none;
  stroke: rgba(165, 243, 252, 0.58);
  stroke-width: 0.72;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.bolt-flare {
  fill: radial-gradient(circle, rgba(0, 229, 255, 0.5), transparent);
  opacity: 0.75;
}

@keyframes skyDischarge {
  0%, 100% { opacity: 0.08; }
  4% { opacity: 0.65; }
  8% { opacity: 0.18; }
  12% { opacity: 0.55; }
  24% { opacity: 0.1; }
  52% { opacity: 0.08; }
  56% { opacity: 0.52; }
  60% { opacity: 0.15; }
  64% { opacity: 0.44; }
  76% { opacity: 0.08; }
}

@keyframes lightningStrikeA {
  0%, 100% { opacity: 0.36; transform: translate3d(0, 0, 0) scale(1); }
  2% { opacity: 1; transform: translate3d(0, 0, 0) scale(1.015); }
  5% { opacity: 0.25; }
  8% { opacity: 0.98; }
  16% { opacity: 0.58; }
  28% { opacity: 0.36; transform: translate3d(0, 0, 0) scale(1); }
}

@keyframes lightningStrikeB {
  0%, 100% { opacity: 0.32; transform: translate3d(0, 0, 0) scale(1); }
  26% { opacity: 0.32; }
  29% { opacity: 1; transform: translate3d(0, 0, 0) scale(1.015); }
  32% { opacity: 0.24; }
  35% { opacity: 0.96; }
  43% { opacity: 0.54; }
  56% { opacity: 0.32; transform: translate3d(0, 0, 0) scale(1); }
}

@keyframes lightningStrikeC {
  0%, 100% { opacity: 0.3; }
  54% { opacity: 0.3; }
  57% { opacity: 0.96; }
  60% { opacity: 0.24; }
  63% { opacity: 0.92; }
  74% { opacity: 0.36; }
}

@keyframes pulseDot {
  0%, 100% { box-shadow: 0 0 0 0 rgba(16, 185, 129, 0.65); }
  50% { box-shadow: 0 0 0 7px rgba(16, 185, 129, 0); }
}

@media (prefers-reduced-motion: reduce) {
  .bg-grid, .bg-aurora, .bg-beam, .bg-beam-v, .bg-flash, .bg-bolt, .bolt-core, .live-dot {
    animation: none !important;
  }
}

/* ==========================================================================
   Layout Container & Utility Classes
   ========================================================================== */
.container {
  width: min(1180px, 100% - 2rem);
  margin-inline: auto;
}

.section {
  padding-block: 4.5rem;
}

.section-head {
  text-align: center;
  max-width: 860px;
  margin: 0 auto 2.75rem;
}

.section-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--cyan);
  background: var(--cyan-soft);
  border: 1px solid rgba(0, 229, 255, 0.25);
  padding: 0.3rem 0.85rem;
  border-radius: var(--radius-pill);
  margin-bottom: 0.85rem;
}

.section-title {
  font-size: clamp(1.65rem, 2.8vw, 2.25rem);
  line-height: 1.28;
  margin: 0 0 0.75rem;
  letter-spacing: -0.02em;
  text-wrap: balance;
}

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

.text-gradient {
  background: linear-gradient(120deg, #ffffff 10%, #67f5ff 55%, #60a5fa 95%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

/* ==========================================================================
   Buttons & CTA Links
   ========================================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.45rem;
  font-weight: 700;
  font-size: 0.96rem;
  padding: 0.78rem 1.45rem;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  cursor: pointer;
  white-space: nowrap;
  transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease, border-color 0.2s ease;
}

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

.btn-primary {
  background: linear-gradient(135deg, #00e5ff 0%, #2563eb 100%);
  color: #031024;
  box-shadow: var(--shadow-cyan);
}

.btn-primary:hover {
  color: #020b1a;
  box-shadow: 0 16px 36px -8px rgba(0, 229, 255, 0.5);
}

.btn-secondary {
  background: rgba(15, 26, 54, 0.82);
  color: var(--text-main);
  border-color: rgba(148, 163, 184, 0.28);
}

.btn-secondary:hover {
  color: var(--cyan);
  border-color: var(--cyan);
  background: rgba(20, 34, 68, 0.95);
}

.btn-sm {
  padding: 0.55rem 1.05rem;
  font-size: 0.88rem;
  border-radius: 10px;
}

.btn-block {
  width: 100%;
}

/* ==========================================================================
   Header & Top-Left Brand Logo (Pure CSS Mobile Toggle)
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(6, 11, 24, 0.78);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-subtle);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: 70px;
}

.brand-logo {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  color: var(--text-main);
  flex-shrink: 0;
}

.brand-logo:hover {
  color: var(--text-main);
  opacity: 0.94;
}

.brand-logo img {
  width: 40px;
  height: 40px;
  filter: drop-shadow(0 0 10px rgba(0, 229, 255, 0.35));
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.1;
}

.brand-name {
  font-size: 1.15rem;
  font-weight: 800;
  letter-spacing: -0.02em;
}

.brand-sub {
  font-size: 0.68rem;
  font-family: var(--font-mono);
  color: var(--cyan);
  letter-spacing: 0.08em;
}

.nav-toggle-check {
  display: none;
}

.nav-toggle-btn {
  display: none;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  border-radius: 10px;
  border: 1px solid var(--border-subtle);
  background: var(--surface);
  color: var(--text-main);
  cursor: pointer;
  font-size: 1.25rem;
  user-select: none;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 1.45rem;
}

.main-nav a {
  color: var(--text-secondary);
  font-size: 0.92rem;
  font-weight: 500;
}

.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;
}

@media (max-width: 960px) {
  .nav-toggle-btn {
    display: inline-flex;
    order: 3;
  }

  .header-inner {
    flex-wrap: wrap;
    padding-block: 0.65rem;
    gap: 0.6rem;
  }

  .main-nav {
    display: none;
    width: 100%;
    flex-direction: column;
    align-items: flex-start;
    gap: 0.75rem;
    padding: 1rem 0 0.5rem;
    border-top: 1px solid var(--border-subtle);
    order: 4;
  }

  .nav-toggle-check:checked ~ .main-nav {
    display: flex;
  }

  .header-actions {
    margin-left: auto;
    order: 2;
  }
}

@media (max-width: 440px) {
  .brand-logo img {
    width: 34px;
    height: 34px;
  }
  .brand-name {
    font-size: 1.02rem;
  }
  .header-actions .btn-sm {
    padding: 0.48rem 0.78rem;
    font-size: 0.82rem;
  }
}

/* ==========================================================================
   Hero Section
   ========================================================================== */
.hero {
  padding-block: 4.5rem 3.5rem;
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
  gap: 2.5rem;
  align-items: center;
}

.hero-grid > * {
  min-width: 0;
}

.live-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  padding: 0.38rem 0.95rem;
  border-radius: var(--radius-pill);
  background: var(--emerald-soft);
  border: 1px solid rgba(16, 185, 129, 0.35);
  color: #6ee7b7;
  font-size: 0.82rem;
  font-weight: 600;
  margin-bottom: 1.2rem;
}

.live-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--emerald);
  animation: pulseDot 2s infinite;
}

.hero-title {
  font-size: clamp(2rem, 4.1vw, 3.15rem);
  line-height: 1.18;
  margin: 0 0 1.15rem;
  letter-spacing: -0.025em;
}

.hero-lead {
  font-size: 1.07rem;
  color: var(--text-secondary);
  margin: 0 0 1.65rem;
  max-width: 620px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.9rem;
  margin-bottom: 1.8rem;
}

.hero-metrics {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.9rem;
}

.metric-chip {
  background: var(--surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 0.85rem 1rem;
}

.metric-val {
  display: block;
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--cyan);
  line-height: 1.25;
}

.metric-lbl {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* Right Hero Telemetry Panel */
.telemetry-card {
  background: linear-gradient(160deg, rgba(14, 25, 52, 0.88), rgba(7, 13, 30, 0.94));
  border: 1px solid rgba(0, 229, 255, 0.28);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  box-shadow: var(--shadow-card), 0 0 50px -20px rgba(0, 229, 255, 0.25);
  backdrop-filter: blur(16px);
}

.telemetry-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: 0.9rem;
  margin-bottom: 1rem;
  border-bottom: 1px solid var(--border-subtle);
}

.telemetry-title {
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--text-main);
}

.telemetry-proto {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  padding: 0.2rem 0.6rem;
  border-radius: 6px;
  background: var(--cyan-soft);
  color: var(--cyan);
  border: 1px solid rgba(0, 229, 255, 0.25);
}

.node-list {
  list-style: none;
  padding: 0;
  margin: 0 0 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.68rem;
}

.node-row {
  display: grid;
  grid-template-columns: 1fr auto auto;
  align-items: center;
  gap: 0.75rem;
  padding: 0.65rem 0.85rem;
  border-radius: 10px;
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid rgba(148, 163, 184, 0.1);
  font-size: 0.88rem;
}

.node-name {
  font-weight: 600;
  color: var(--text-main);
}

.node-tag {
  font-size: 0.72rem;
  color: var(--text-muted);
  background: rgba(148, 163, 184, 0.12);
  padding: 0.15rem 0.5rem;
  border-radius: 6px;
}

.node-ping {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 700;
  color: #34d399;
}

.telemetry-unlock {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  padding-top: 0.9rem;
  border-top: 1px solid var(--border-subtle);
}

.unlock-pill {
  font-size: 0.75rem;
  padding: 0.25rem 0.62rem;
  border-radius: 6px;
  background: rgba(59, 130, 246, 0.14);
  border: 1px solid rgba(59, 130, 246, 0.28);
  color: #bfdbfe;
}

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

@media (max-width: 560px) {
  .hero {
    padding-block: 2.6rem 2.2rem;
  }
  .hero-title {
    font-size: clamp(1.65rem, 7.2vw, 2.2rem);
  }
  .hero-actions .btn {
    width: 100%;
    white-space: normal;
    text-align: center;
  }
  .hero-metrics {
    grid-template-columns: minmax(0, 1fr);
  }
  .telemetry-card {
    padding: 1.15rem;
  }
  .telemetry-top {
    flex-wrap: wrap;
    gap: 0.5rem;
  }
  .node-row {
    grid-template-columns: 1fr auto;
    gap: 0.4rem 0.65rem;
    font-size: 0.84rem;
  }
  .node-tag {
    display: none;
  }
}

/* ==========================================================================
   GEO Quick Summary / Entity Fact Strip
   ========================================================================== */
.tldr-box {
  background: linear-gradient(135deg, rgba(0, 229, 255, 0.08), rgba(59, 130, 246, 0.08));
  border: 1px solid rgba(0, 229, 255, 0.24);
  border-left: 4px solid var(--cyan);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.45rem;
  margin-block: 1.5rem;
}

.tldr-label {
  display: inline-block;
  font-size: 0.76rem;
  font-weight: 800;
  letter-spacing: 0.06em;
  color: var(--cyan);
  text-transform: uppercase;
  margin-bottom: 0.4rem;
}

.tldr-box p {
  margin: 0;
  color: var(--text-secondary);
  font-size: 0.96rem;
}

/* ==========================================================================
   Pricing Section — STRICTLY SAME ROW ON TABLET/DESKTOP (所有价格同排)
   ========================================================================== */
.pricing-grid {
  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);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 2rem 1.65rem;
  box-shadow: var(--shadow-card);
  transition: transform 0.25s ease, border-color 0.25s ease, background 0.25s ease;
}

.pricing-card:hover {
  transform: translateY(-4px);
  border-color: rgba(0, 229, 255, 0.45);
  background: var(--surface-hover);
}

.pricing-card.is-featured {
  background: linear-gradient(175deg, rgba(14, 30, 64, 0.92), rgba(9, 18, 40, 0.96));
  border: 1.5px solid var(--cyan);
  box-shadow: var(--shadow-card), 0 0 42px -14px rgba(0, 229, 255, 0.4);
}

.plan-badge {
  position: absolute;
  top: -13px;
  right: 1.4rem;
  background: linear-gradient(135deg, #00e5ff, #3b82f6);
  color: #031024;
  font-size: 0.74rem;
  font-weight: 800;
  padding: 0.28rem 0.85rem;
  border-radius: var(--radius-pill);
  letter-spacing: 0.03em;
}

.plan-tier {
  font-size: 1.25rem;
  font-weight: 800;
  margin: 0 0 0.35rem;
}

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

.plan-price-wrap {
  display: flex;
  align-items: baseline;
  gap: 0.35rem;
  margin-bottom: 0.35rem;
}

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

.plan-amount {
  font-size: 2.65rem;
  font-weight: 900;
  line-height: 1;
  color: #ffffff;
  letter-spacing: -0.03em;
}

.plan-cycle {
  font-size: 0.92rem;
  color: var(--text-muted);
}

.plan-annual {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.82rem;
  font-weight: 600;
  color: #6ee7b7;
  background: var(--emerald-soft);
  border: 1px solid rgba(16, 185, 129, 0.28);
  padding: 0.25rem 0.68rem;
  border-radius: 8px;
  margin-bottom: 1.35rem;
  align-self: flex-start;
}

.plan-specs {
  list-style: none;
  padding: 1.15rem 0 0;
  margin: 0 0 1.65rem;
  border-top: 1px solid var(--border-subtle);
  display: flex;
  flex-direction: column;
  gap: 0.7rem;
  font-size: 0.93rem;
  color: var(--text-secondary);
}

.plan-specs li {
  display: flex;
  align-items: flex-start;
  gap: 0.55rem;
}

.plan-specs li::before {
  content: "✓";
  color: var(--cyan);
  font-weight: 900;
  flex-shrink: 0;
}

.pricing-card .btn {
  margin-top: auto;
}

@media (max-width: 767px) {
  .pricing-grid {
    grid-template-columns: minmax(0, 1fr);
  }
}

.pricing-footnote {
  margin-top: 1.5rem;
  text-align: center;
  font-size: 0.9rem;
  color: var(--text-muted);
}

/* Comparison Table */
.table-wrap {
  margin-top: 2rem;
  overflow-x: auto;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-subtle);
  background: var(--surface);
}

.spec-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.93rem;
  min-width: 640px;
}

.spec-table th,
.spec-table td {
  padding: 0.95rem 1.15rem;
  text-align: left;
  border-bottom: 1px solid var(--border-subtle);
}

.spec-table thead th {
  background: rgba(0, 229, 255, 0.08);
  color: #ffffff;
  font-weight: 700;
}

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

.spec-table tbody tr:hover {
  background: rgba(255, 255, 255, 0.025);
}

.pricing-grid > *,
.grid-3 > *,
.grid-2 > *,
.articles-grid > *,
.reviews-grid > * {
  min-width: 0;
}

@media (max-width: 560px) {
  .btn {
    white-space: normal;
    text-align: center;
  }
}

/* ==========================================================================
   Feature / Client / Architecture Grids
   ========================================================================== */
.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1.35rem;
}

.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1.5rem;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.55rem;
  box-shadow: var(--shadow-card);
  transition: border-color 0.22s ease, transform 0.22s ease;
}

.card:hover {
  border-color: rgba(0, 229, 255, 0.36);
  transform: translateY(-3px);
}

.card-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: 12px;
  background: var(--cyan-soft);
  border: 1px solid rgba(0, 229, 255, 0.25);
  color: var(--cyan);
  font-weight: 800;
  font-size: 1.15rem;
  margin-bottom: 1rem;
}

.card h3 {
  font-size: 1.12rem;
  margin: 0 0 0.55rem;
  color: #ffffff;
}

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

@media (max-width: 900px) {
  .grid-3 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 640px) {
  .grid-3, .grid-2 {
    grid-template-columns: minmax(0, 1fr);
  }
}

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

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

@media (max-width: 640px) {
  .articles-grid {
    grid-template-columns: minmax(0, 1fr);
  }
}

.article-card {
  display: flex;
  flex-direction: column;
  background: var(--surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.45rem;
  transition: transform 0.22s ease, border-color 0.22s ease;
}

.article-card:hover {
  transform: translateY(-4px);
  border-color: rgba(0, 229, 255, 0.45);
}

.article-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
}

.article-tag {
  background: var(--cyan-soft);
  color: var(--cyan);
  border: 1px solid rgba(0, 229, 255, 0.22);
  padding: 0.18rem 0.6rem;
  border-radius: 6px;
  font-weight: 600;
}

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

.article-card h3 a {
  color: #ffffff;
}

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

.article-excerpt {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin: 0 0 1.2rem;
  flex-grow: 1;
}

.article-more {
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--cyan);
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
}

/* Single Article Shell */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.45rem;
  font-size: 0.86rem;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
}

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

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

.article-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 310px;
  gap: 2.2rem;
  align-items: start;
  padding-block: 2.5rem 4rem;
}

@media (max-width: 960px) {
  .article-layout {
    grid-template-columns: minmax(0, 1fr);
  }
}

.article-main {
  background: var(--surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: clamp(1.5rem, 3.2vw, 2.75rem);
  box-shadow: var(--shadow-card);
}

.article-header {
  border-bottom: 1px solid var(--border-subtle);
  padding-bottom: 1.35rem;
  margin-bottom: 1.65rem;
}

.article-header h1 {
  font-size: clamp(1.6rem, 2.9vw, 2.25rem);
  line-height: 1.3;
  margin: 0.75rem 0 0.9rem;
}

.article-info-row {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  font-size: 0.86rem;
  color: var(--text-muted);
}

.article-prose {
  font-size: 1.03rem;
  line-height: 1.88;
  color: var(--text-secondary);
}

.article-prose h2 {
  font-size: 1.38rem;
  color: #ffffff;
  margin: 2.1rem 0 0.85rem;
  padding-left: 0.8rem;
  border-left: 3.5px solid var(--cyan);
  line-height: 1.35;
}

.article-prose h3 {
  font-size: 1.12rem;
  color: #e2e8f0;
  margin: 1.45rem 0 0.6rem;
}

.article-prose p {
  margin: 0 0 1.15rem;
}

.article-prose ul,
.article-prose ol {
  margin: 0 0 1.25rem;
  padding-left: 1.35rem;
}

.article-prose li {
  margin-bottom: 0.5rem;
}

.article-prose strong {
  color: #ffffff;
}

.article-prose code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  background: rgba(0, 229, 255, 0.1);
  color: #7df3ff;
  padding: 0.14rem 0.42rem;
  border-radius: 5px;
}

.inline-cta-banner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin: 2rem 0;
  padding: 1.35rem 1.5rem;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, rgba(0, 229, 255, 0.12), rgba(37, 99, 235, 0.16));
  border: 1px solid rgba(0, 229, 255, 0.35);
}

.inline-cta-banner p {
  margin: 0;
  color: var(--text-main);
  font-size: 0.96rem;
}

.article-sidebar {
  display: flex;
  flex-direction: column;
  gap: 1.35rem;
  position: sticky;
  top: 90px;
}

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

.sidebar-box h3 {
  font-size: 1.02rem;
  margin: 0 0 0.85rem;
  color: #ffffff;
}

.sidebar-links {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
  font-size: 0.89rem;
}

.sidebar-links a {
  color: var(--text-secondary);
  display: block;
  padding-bottom: 0.45rem;
  border-bottom: 1px dashed rgba(148, 163, 184, 0.15);
}

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

.article-pager {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  margin-top: 2.25rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border-subtle);
}

.pager-link {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  padding: 1rem 1.15rem;
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--border-subtle);
}

.pager-link:hover {
  border-color: var(--cyan);
  background: rgba(0, 229, 255, 0.06);
}

.pager-dir {
  font-size: 0.76rem;
  color: var(--text-muted);
}

.pager-title {
  font-size: 0.92rem;
  font-weight: 700;
  color: var(--text-main);
}

@media (max-width: 640px) {
  .article-pager {
    grid-template-columns: minmax(0, 1fr);
  }
}

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

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

@media (max-width: 600px) {
  .reviews-grid {
    grid-template-columns: minmax(0, 1fr);
  }
}

.review-card {
  display: flex;
  flex-direction: column;
  background: var(--surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.45rem;
}

.review-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.75rem;
}

.review-stars {
  color: #fbbf24;
  letter-spacing: 0.08em;
  font-size: 0.95rem;
}

.review-plan {
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.18rem 0.55rem;
  border-radius: 6px;
  background: var(--cyan-soft);
  color: var(--cyan);
}

.review-body {
  margin: 0 0 1rem;
  font-size: 0.93rem;
  color: var(--text-secondary);
  flex-grow: 1;
}

.review-author {
  font-size: 0.82rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border-subtle);
  padding-top: 0.75rem;
}

/* ==========================================================================
   Pure HTML/CSS Interactive FAQ Accordion (<details>/<summary>)
   ========================================================================== */
.faq-list {
  max-width: 880px;
  margin-inline: auto;
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

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

.faq-item[open] {
  border-color: rgba(0, 229, 255, 0.45);
}

.faq-q {
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1.15rem 1.35rem;
  font-weight: 700;
  font-size: 1.02rem;
  color: #ffffff;
  cursor: pointer;
  user-select: none;
}

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

.faq-q::after {
  content: "+";
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: 8px;
  background: var(--cyan-soft);
  color: var(--cyan);
  font-size: 1.15rem;
  font-weight: 800;
  flex-shrink: 0;
  transition: transform 0.2s ease;
}

.faq-item[open] .faq-q::after {
  content: "−";
  background: var(--cyan);
  color: #031024;
}

.faq-a {
  padding: 0 1.35rem 1.25rem;
  color: var(--text-secondary);
  font-size: 0.95rem;
  border-top: 1px solid rgba(148, 163, 184, 0.1);
  padding-top: 0.95rem;
}

.faq-a p {
  margin: 0;
}

/* ==========================================================================
   Bottom CTA & Footer (with Outbound Authority Links)
   ========================================================================== */
.cta-banner {
  background: linear-gradient(135deg, rgba(0, 229, 255, 0.14), rgba(59, 130, 246, 0.18));
  border: 1px solid rgba(0, 229, 255, 0.35);
  border-radius: var(--radius-lg);
  padding: clamp(2rem, 4vw, 3.2rem);
  text-align: center;
}

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

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

.site-footer {
  border-top: 1px solid var(--border-subtle);
  background: rgba(4, 8, 18, 0.92);
  padding-block: 3.5rem 2rem;
  margin-top: 3rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1.1fr 1.1fr;
  gap: 2rem;
  margin-bottom: 2.5rem;
}

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

@media (max-width: 560px) {
  .footer-grid {
    grid-template-columns: minmax(0, 1fr);
  }
}

.footer-col h4 {
  font-size: 0.96rem;
  color: #ffffff;
  margin: 0 0 1rem;
}

.footer-links {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
  font-size: 0.88rem;
}

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

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

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border-subtle);
  font-size: 0.82rem;
  color: var(--text-muted);
}