/* ============================================================
   光速云 Design System v2.0 — 极简玻璃拟态风
   gsycloud.homes | 2025
   ============================================================ */

/* ── Google Fonts ─────────────────────────────────────────── */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800;900&family=Noto+Sans+SC:wght@300;400;500;700;900&display=swap');

/* ── Design Tokens ────────────────────────────────────────── */
:root {
  /* Color Palette */
  --bg-primary:       #E2E8F0;
  --bg-secondary:     #EFF3F9;
  --bg-card:          rgba(255, 255, 255, 0.60);
  --bg-card-hover:    rgba(255, 255, 255, 0.80);
  --bg-nav:           rgba(242, 246, 252, 0.82);
  --bg-footer:        #0F172A;

  /* Brand Colors */
  --blue-primary:     #3B82F6;
  --blue-bright:      #2563EB;
  --blue-dark:        #1D4ED8;
  --blue-light:       #DBEAFE;
  --blue-pale:        #EFF6FF;
  --purple-accent:    #A78BFA;
  --purple-dark:      #7C3AED;
  --purple-light:     #EDE9FE;
  --cyan-accent:      #06B6D4;
  --cyan-light:       #CFFAFE;

  /* Text */
  --text-primary:     #0F172A;
  --text-secondary:   #334155;
  --text-muted:       #64748B;
  --text-light:       #94A3B8;
  --text-on-dark:     #F8FAFC;

  /* State Colors */
  --success:          #10B981;
  --success-bg:       #D1FAE5;
  --warning:          #F59E0B;
  --warning-bg:       #FEF3C7;
  --danger:           #EF4444;
  --danger-bg:        #FEE2E2;
  --info:             #3B82F6;
  --info-bg:          #DBEAFE;

  /* Glass System */
  --glass-bg:         rgba(255, 255, 255, 0.60);
  --glass-bg-strong:  rgba(255, 255, 255, 0.80);
  --glass-border:     rgba(255, 255, 255, 0.90);
  --glass-border-sub: rgba(255, 255, 255, 0.55);
  --glass-shadow:     0 8px 32px rgba(59, 130, 246, 0.10), 0 1px 3px rgba(0,0,0,0.06);
  --glass-shadow-lg:  0 20px 60px rgba(59, 130, 246, 0.14), 0 4px 12px rgba(0,0,0,0.08);
  --glass-shadow-hover: 0 24px 64px rgba(59, 130, 246, 0.18), 0 6px 20px rgba(0,0,0,0.10);
  --glass-inner:      inset 0 1px 0 rgba(255, 255, 255, 0.95);
  --glass-blur:       blur(20px) saturate(180%);
  --glass-blur-sm:    blur(12px) saturate(160%);

  /* Border */
  --border-subtle:    rgba(148, 163, 184, 0.20);
  --border-card:      rgba(255, 255, 255, 0.90);
  --border-brand:     rgba(59, 130, 246, 0.30);

  /* Gradients */
  --grad-brand:       linear-gradient(135deg, #3B82F6 0%, #A78BFA 100%);
  --grad-blue:        linear-gradient(135deg, #3B82F6 0%, #2563EB 100%);
  --grad-purple:      linear-gradient(135deg, #A78BFA 0%, #7C3AED 100%);
  --grad-hero:        linear-gradient(135deg, rgba(59,130,246,0.08) 0%, rgba(167,139,250,0.06) 100%);
  --grad-card:        linear-gradient(145deg, rgba(255,255,255,0.70) 0%, rgba(255,255,255,0.45) 100%);
  --grad-text:        linear-gradient(135deg, #3B82F6 0%, #A78BFA 100%);

  /* Spacing */
  --space-xs:   4px;
  --space-sm:   8px;
  --space-md:   16px;
  --space-lg:   24px;
  --space-xl:   40px;
  --space-2xl:  64px;
  --space-3xl:  96px;

  /* Border Radius */
  --radius-sm:  8px;
  --radius-md:  12px;
  --radius-lg:  20px;
  --radius-xl:  28px;
  --radius-2xl: 40px;
  --radius-full: 9999px;

  /* Typography */
  --font-sans:  'Inter', 'Noto Sans SC', system-ui, sans-serif;
  --font-zh:    'Noto Sans SC', 'Inter', sans-serif;

  /* Transitions */
  --ease-out:   cubic-bezier(0.16, 1, 0.3, 1);
  --ease-in:    cubic-bezier(0.4, 0, 1, 1);
  --dur-fast:   150ms;
  --dur-base:   250ms;
  --dur-slow:   400ms;

  /* Layout */
  --container:  1200px;
  --nav-h:      72px;
}

/* ── Reset & Base ─────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
  position: relative;
}

/* Page background with light orbs + tech grid */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background:
    radial-gradient(ellipse 60% 50% at 15% 15%, rgba(59,130,246,0.10) 0%, transparent 60%),
    radial-gradient(ellipse 50% 60% at 85% 80%, rgba(167,139,250,0.10) 0%, transparent 60%),
    radial-gradient(ellipse 40% 40% at 50% 50%, rgba(6,182,212,0.04) 0%, transparent 60%),
    linear-gradient(135deg, #E2E8F0 0%, #EAF0FB 40%, #EDE9FE 100%);
  z-index: -2;
  pointer-events: none;
}

/* Tech grid lines */
body::after {
  content: '';
  position: fixed;
  inset: 0;
  background-image:
    linear-gradient(rgba(59,130,246,0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(59,130,246,0.04) 1px, transparent 1px);
  background-size: 60px 60px;
  z-index: -1;
  pointer-events: none;
  mask-image: radial-gradient(ellipse at center, rgba(0,0,0,0.4) 0%, transparent 80%);
}

/* Floating orb decoration */
.page-body {
  position: relative;
}

a { color: var(--blue-primary); text-decoration: none; transition: color var(--dur-fast); }
a:hover { color: var(--blue-bright); }
img { max-width: 100%; display: block; }
ul, ol { list-style: none; }
button { cursor: pointer; border: none; background: none; font-family: inherit; }

/* ── Reading Progress ─────────────────────────────────────── */
.reading-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  z-index: 1000;
  background: rgba(59,130,246,0.12);
}
.reading-progress-bar {
  height: 100%;
  width: 0%;
  background: var(--grad-brand);
  transition: width 100ms linear;
  border-radius: 0 2px 2px 0;
  box-shadow: 0 0 12px rgba(59,130,246,0.5);
}

/* ── Container ────────────────────────────────────────────── */
.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

/* ── Navigation ───────────────────────────────────────────── */
.gsyc-nav {
  position: sticky;
  top: 0;
  z-index: 200;
  height: var(--nav-h);
  background: rgba(242, 246, 252, 0.82);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border-bottom: 1px solid rgba(255,255,255,0.80);
  box-shadow: 0 1px 0 rgba(148,163,184,0.15), 0 4px 20px rgba(59,130,246,0.06);
  transition: background var(--dur-base), box-shadow var(--dur-base);
}

.gsyc-nav.scrolled {
  background: rgba(235, 242, 252, 0.92);
  box-shadow: 0 1px 0 rgba(148,163,184,0.20), 0 8px 32px rgba(59,130,246,0.10);
}

.nav-inner {
  display: flex;
  align-items: center;
  gap: var(--space-xl);
  height: 100%;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  text-decoration: none;
  flex-shrink: 0;
}

.nav-logo-icon {
  width: 36px;
  height: 36px;
  background: var(--grad-brand);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  box-shadow: 0 4px 12px rgba(59,130,246,0.30);
  flex-shrink: 0;
}

.nav-logo-text {
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--text-primary);
  background: var(--grad-text);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: -0.01em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 4px;
  flex: 1;
}

.nav-links li a {
  display: block;
  padding: 7px 14px;
  font-size: .88rem;
  font-weight: 500;
  color: var(--text-secondary);
  border-radius: var(--radius-sm);
  transition: all var(--dur-fast);
  white-space: nowrap;
  text-decoration: none;
}

.nav-links li a:hover {
  color: var(--blue-primary);
  background: rgba(59,130,246,0.08);
}

.nav-links li a.active {
  color: var(--blue-primary);
  background: rgba(59,130,246,0.10);
  font-weight: 600;
}

.nav-cta {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 9px 20px;
  background: var(--grad-brand);
  color: #fff !important;
  border-radius: var(--radius-full);
  font-size: .88rem;
  font-weight: 700;
  white-space: nowrap;
  box-shadow: 0 4px 16px rgba(59,130,246,0.30);
  transition: all var(--dur-base) var(--ease-out);
  flex-shrink: 0;
  text-decoration: none;
  -webkit-text-fill-color: #fff;
}

.nav-cta:hover {
  transform: translateY(-1px);
  box-shadow: 0 8px 24px rgba(59,130,246,0.40);
  color: #fff !important;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 8px;
  margin-left: auto;
}
.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-secondary);
  border-radius: 2px;
  transition: all var(--dur-base);
}

/* ── Buttons ──────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 28px;
  font-size: .95rem;
  font-weight: 700;
  border-radius: var(--radius-full);
  border: none;
  cursor: pointer;
  transition: all var(--dur-base) var(--ease-out);
  text-decoration: none;
  white-space: nowrap;
  font-family: var(--font-sans);
  letter-spacing: -0.01em;
}

.btn-primary {
  background: var(--grad-brand);
  color: #fff;
  box-shadow: 0 4px 16px rgba(59,130,246,0.30);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 28px rgba(59,130,246,0.40);
  color: #fff;
}
.btn-primary:active { transform: translateY(0); }

.btn-secondary {
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur-sm);
  -webkit-backdrop-filter: var(--glass-blur-sm);
  color: var(--blue-primary);
  border: 1.5px solid rgba(59,130,246,0.30);
  box-shadow: var(--glass-shadow);
}
.btn-secondary:hover {
  background: var(--glass-bg-strong);
  transform: translateY(-2px);
  box-shadow: var(--glass-shadow-hover);
  color: var(--blue-bright);
  border-color: rgba(59,130,246,0.50);
}

.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
  border: 1.5px solid rgba(148,163,184,0.30);
}
.btn-ghost:hover {
  background: rgba(255,255,255,0.60);
  color: var(--text-primary);
}

.btn-sm { padding: 8px 18px; font-size: .82rem; }
.btn-lg { padding: 16px 36px; font-size: 1.05rem; }

/* ── Glass Card ───────────────────────────────────────────── */
.gsyc-card {
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: 28px;
  box-shadow: var(--glass-shadow), var(--glass-inner);
  transition: all var(--dur-base) var(--ease-out);
  position: relative;
  overflow: hidden;
}

.gsyc-card::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(255,255,255,0.40) 0%, transparent 60%);
  pointer-events: none;
  border-radius: inherit;
}

.gsyc-card:hover {
  background: var(--glass-bg-strong);
  transform: translateY(-4px);
  box-shadow: var(--glass-shadow-hover), var(--glass-inner);
  border-color: rgba(255,255,255,1);
}

.gsyc-card-icon {
  font-size: 1.8rem;
  margin-bottom: 14px;
  display: block;
  filter: drop-shadow(0 2px 4px rgba(59,130,246,0.15));
}

.gsyc-card-title {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 8px;
  line-height: 1.4;
}

.gsyc-card-desc {
  font-size: .9rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* Plan Cards */
.plan-card {
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-xl);
  padding: 36px 28px;
  box-shadow: var(--glass-shadow), var(--glass-inner);
  transition: all var(--dur-base) var(--ease-out);
  position: relative;
  overflow: hidden;
  text-align: center;
}

.plan-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: linear-gradient(90deg, transparent, rgba(59,130,246,0.3), transparent);
}

.plan-card.featured {
  background: linear-gradient(145deg, rgba(59,130,246,0.12) 0%, rgba(167,139,250,0.08) 100%);
  border-color: rgba(59,130,246,0.35);
  box-shadow: 0 12px 40px rgba(59,130,246,0.18), var(--glass-inner);
  transform: scale(1.02);
}

.plan-card.featured::before {
  background: var(--grad-brand);
  height: 4px;
}

.plan-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--glass-shadow-hover), var(--glass-inner);
}

.plan-card.featured:hover {
  transform: scale(1.02) translateY(-6px);
}

/* ── Hero Section ─────────────────────────────────────────── */
.gsyc-hero {
  position: relative;
  padding: calc(var(--nav-h) + 60px) 0 80px;
  overflow: hidden;
}

.gsyc-hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 70% 60% at 80% 20%, rgba(167,139,250,0.12) 0%, transparent 60%),
    radial-gradient(ellipse 60% 70% at 20% 80%, rgba(59,130,246,0.10) 0%, transparent 60%);
  pointer-events: none;
}

/* Decorative orbs */
.orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  pointer-events: none;
}

.orb-blue { background: rgba(59,130,246,0.18); }
.orb-purple { background: rgba(167,139,250,0.15); }
.orb-cyan { background: rgba(6,182,212,0.12); }

/* Tech lines decoration */
.tech-lines {
  position: absolute;
  inset: 0;
  overflow: hidden;
  pointer-events: none;
  opacity: 0.4;
}

.tech-lines::before {
  content: '';
  position: absolute;
  width: 600px;
  height: 600px;
  top: -100px;
  right: -100px;
  border: 1px solid rgba(59,130,246,0.15);
  border-radius: 50%;
  animation: rotate 30s linear infinite;
}

.tech-lines::after {
  content: '';
  position: absolute;
  width: 400px;
  height: 400px;
  top: 0;
  right: 50px;
  border: 1px solid rgba(167,139,250,0.12);
  border-radius: 50%;
  animation: rotate 20s linear infinite reverse;
}

@keyframes rotate {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

.hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur-sm);
  -webkit-backdrop-filter: var(--glass-blur-sm);
  border: 1px solid rgba(59,130,246,0.25);
  border-radius: var(--radius-full);
  font-size: .82rem;
  font-weight: 600;
  color: var(--blue-primary);
  margin-bottom: 24px;
  box-shadow: 0 2px 12px rgba(59,130,246,0.10);
}

.hero-title {
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  font-weight: 900;
  color: var(--text-primary);
  line-height: 1.1;
  letter-spacing: -0.03em;
  margin-bottom: 20px;
}

.hero-title .grad {
  background: var(--grad-text);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-desc {
  font-size: 1.1rem;
  color: var(--text-secondary);
  max-width: 560px;
  line-height: 1.8;
  margin-bottom: 36px;
}

.hero-cta {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

/* ── Sections ─────────────────────────────────────────────── */
.section {
  padding: var(--space-3xl) 0;
}

.section-sm {
  padding: var(--space-2xl) 0;
}

.section-bg {
  background: rgba(255,255,255,0.35);
  backdrop-filter: blur(8px);
  border-top: 1px solid rgba(255,255,255,0.70);
  border-bottom: 1px solid rgba(255,255,255,0.70);
}

.section-header {
  text-align: center;
  margin-bottom: 56px;
}

.section-label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: .78rem;
  font-weight: 700;
  letter-spacing: .10em;
  text-transform: uppercase;
  color: var(--blue-primary);
  margin-bottom: 14px;
  background: rgba(59,130,246,0.08);
  padding: 5px 14px;
  border-radius: var(--radius-full);
  border: 1px solid rgba(59,130,246,0.15);
}

.section-title {
  font-size: clamp(1.7rem, 3.5vw, 2.4rem);
  font-weight: 800;
  color: var(--text-primary);
  letter-spacing: -0.02em;
  line-height: 1.25;
  margin-bottom: 16px;
}

.section-desc {
  font-size: 1rem;
  color: var(--text-secondary);
  max-width: 520px;
  margin: 0 auto;
  line-height: 1.8;
}

/* ── Grids ────────────────────────────────────────────────── */
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.grid-auto { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 20px; }

/* ── Quick Answer Box ─────────────────────────────────────── */
.gsyc-quick-answer {
  background: linear-gradient(135deg, rgba(59,130,246,0.08) 0%, rgba(167,139,250,0.06) 100%);
  backdrop-filter: var(--glass-blur-sm);
  -webkit-backdrop-filter: var(--glass-blur-sm);
  border: 1px solid rgba(59,130,246,0.20);
  border-left: 4px solid var(--blue-primary);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  padding: 20px 24px;
  margin: 24px 0;
  position: relative;
  box-shadow: 0 4px 16px rgba(59,130,246,0.08), inset 0 1px 0 rgba(255,255,255,0.60);
}

.gsyc-quick-answer::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(255,255,255,0.40) 0%, transparent 60%);
  border-radius: inherit;
  pointer-events: none;
}

.qa-label {
  font-size: .78rem;
  font-weight: 800;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--blue-primary);
  margin-bottom: 8px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.qa-content {
  font-size: .95rem;
  color: var(--text-primary);
  line-height: 1.8;
  font-weight: 400;
}

/* ── Definition Box ───────────────────────────────────────── */
.gsyc-definition {
  background: rgba(59,130,246,0.05);
  border: 1px solid rgba(59,130,246,0.15);
  border-radius: var(--radius-md);
  padding: 16px 20px;
  margin: 16px 0;
  position: relative;
  overflow: hidden;
  box-shadow: inset 0 1px 0 rgba(255,255,255,0.60);
}

.gsyc-definition::before {
  content: 'DEF';
  position: absolute;
  top: 12px;
  right: 14px;
  font-size: .65rem;
  font-weight: 800;
  letter-spacing: .1em;
  color: rgba(59,130,246,0.35);
}

.gsyc-definition p, .gsyc-definition {
  font-size: .92rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ── Alerts ───────────────────────────────────────────────── */
.gsyc-alert {
  display: flex;
  gap: 14px;
  padding: 16px 20px;
  border-radius: var(--radius-md);
  margin: 20px 0;
  backdrop-filter: var(--glass-blur-sm);
  -webkit-backdrop-filter: var(--glass-blur-sm);
  box-shadow: inset 0 1px 0 rgba(255,255,255,0.70);
}

.alert-info {
  background: rgba(219,234,254,0.60);
  border: 1px solid rgba(59,130,246,0.20);
  border-left: 3px solid var(--blue-primary);
}

.alert-warning {
  background: rgba(254,243,199,0.60);
  border: 1px solid rgba(245,158,11,0.20);
  border-left: 3px solid var(--warning);
}

.alert-success {
  background: rgba(209,250,229,0.60);
  border: 1px solid rgba(16,185,129,0.20);
  border-left: 3px solid var(--success);
}

.alert-danger {
  background: rgba(254,226,226,0.60);
  border: 1px solid rgba(239,68,68,0.20);
  border-left: 3px solid var(--danger);
}

.alert-icon { font-size: 1.2rem; flex-shrink: 0; margin-top: 1px; }
.alert-body { flex: 1; }
.alert-title { font-size: .9rem; font-weight: 700; color: var(--text-primary); margin-bottom: 4px; }
.alert-text { font-size: .88rem; color: var(--text-secondary); line-height: 1.7; }

/* ── Steps Component ──────────────────────────────────────── */
.gsyc-steps { display: flex; flex-direction: column; gap: 0; margin: 24px 0; }

.gsyc-step {
  display: flex;
  gap: 20px;
  position: relative;
}

.gsyc-step:not(:last-child)::before {
  content: '';
  position: absolute;
  left: 19px;
  top: 42px;
  bottom: -8px;
  width: 2px;
  background: linear-gradient(to bottom, rgba(59,130,246,0.25), rgba(167,139,250,0.10));
}

.step-num {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur-sm);
  border: 2px solid rgba(59,130,246,0.30);
  box-shadow: 0 4px 12px rgba(59,130,246,0.10), inset 0 1px 0 rgba(255,255,255,0.80);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: .85rem;
  font-weight: 800;
  color: var(--blue-primary);
  flex-shrink: 0;
  position: relative;
  z-index: 1;
}

.step-body {
  flex: 1;
  padding-bottom: 28px;
}

.step-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 6px;
  line-height: 1.4;
}

.step-desc {
  font-size: .9rem;
  color: var(--text-secondary);
  line-height: 1.75;
}

/* ── FAQ ──────────────────────────────────────────────────── */
.gsyc-faq-list { display: flex; flex-direction: column; gap: 10px; margin: 24px 0; }

.gsyc-faq-item {
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur-sm);
  -webkit-backdrop-filter: var(--glass-blur-sm);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: 0 2px 12px rgba(59,130,246,0.06), var(--glass-inner);
  transition: box-shadow var(--dur-base);
}

.gsyc-faq-item:hover {
  box-shadow: 0 6px 24px rgba(59,130,246,0.10), var(--glass-inner);
}

.faq-question {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  padding: 18px 22px;
  text-align: left;
  background: none;
  border: none;
  cursor: pointer;
  font-family: inherit;
  font-size: .95rem;
  font-weight: 600;
  color: var(--text-primary);
  transition: all var(--dur-fast);
}

.faq-question:hover { color: var(--blue-primary); background: rgba(59,130,246,0.04); }
.faq-question[aria-expanded="true"] { color: var(--blue-primary); }

.faq-icon {
  font-size: 1.2rem;
  font-weight: 400;
  color: var(--blue-primary);
  flex-shrink: 0;
  transition: transform var(--dur-base) var(--ease-out);
  line-height: 1;
}

.faq-question[aria-expanded="true"] .faq-icon { transform: rotate(45deg); }

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--dur-slow) var(--ease-out);
}

.faq-answer.open { max-height: 600px; }

.faq-answer-inner {
  padding: 0 22px 20px;
  font-size: .92rem;
  color: var(--text-secondary);
  line-height: 1.8;
  border-top: 1px solid rgba(148,163,184,0.12);
  padding-top: 14px;
}

/* ── Breadcrumb ───────────────────────────────────────────── */
.gsyc-breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: .82rem;
  color: var(--text-muted);
  margin-bottom: 24px;
  flex-wrap: wrap;
}

.gsyc-breadcrumb a {
  color: var(--text-muted);
  transition: color var(--dur-fast);
}

.gsyc-breadcrumb a:hover { color: var(--blue-primary); }
.gsyc-breadcrumb .sep { color: rgba(148,163,184,0.60); }
.gsyc-breadcrumb .current { color: var(--text-secondary); font-weight: 500; }

/* ── Article Layout ───────────────────────────────────────── */
.article-layout {
  display: grid;
  grid-template-columns: 1fr 280px;
  gap: 48px;
  align-items: start;
}

.article-content { min-width: 0; }

.article-meta {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 24px;
}

.meta-item {
  font-size: .8rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 5px;
}

/* ── TOC Sidebar ──────────────────────────────────────────── */
.article-sidebar { position: sticky; top: calc(var(--nav-h) + 20px); }

.gsyc-toc {
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: 22px;
  box-shadow: var(--glass-shadow), var(--glass-inner);
}

.toc-title {
  font-size: .78rem;
  font-weight: 800;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--blue-primary);
  margin-bottom: 14px;
  padding-bottom: 10px;
  border-bottom: 1px solid rgba(59,130,246,0.12);
}

.gsyc-toc ul { display: flex; flex-direction: column; gap: 2px; }

.gsyc-toc ul li a {
  display: block;
  padding: 6px 10px;
  font-size: .84rem;
  color: var(--text-secondary);
  border-radius: var(--radius-sm);
  transition: all var(--dur-fast);
  text-decoration: none;
  line-height: 1.5;
}

.gsyc-toc ul li a:hover {
  color: var(--blue-primary);
  background: rgba(59,130,246,0.07);
}

.gsyc-toc ul li.toc-h3 a { padding-left: 22px; font-size: .82rem; opacity: 0.85; }
.gsyc-toc ul li.active > a { color: var(--blue-primary); font-weight: 600; background: rgba(59,130,246,0.08); }

/* ── Score Bars ───────────────────────────────────────────── */
.gsyc-score-bar { display: flex; flex-direction: column; gap: 10px; }

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

.score-label {
  font-size: .82rem;
  font-weight: 500;
  color: var(--text-secondary);
  min-width: 48px;
  flex-shrink: 0;
}

.score-track {
  flex: 1;
  height: 6px;
  background: rgba(148,163,184,0.20);
  border-radius: 3px;
  overflow: hidden;
}

.score-fill {
  height: 100%;
  background: var(--grad-brand);
  border-radius: 3px;
  transition: width 1s var(--ease-out);
  box-shadow: 0 0 6px rgba(59,130,246,0.40);
}

.score-value {
  font-size: .82rem;
  font-weight: 700;
  color: var(--blue-primary);
  min-width: 28px;
  text-align: right;
}

/* ── Tags ─────────────────────────────────────────────────── */
.gsyc-tag {
  display: inline-flex;
  align-items: center;
  padding: 4px 12px;
  font-size: .75rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  letter-spacing: .02em;
  backdrop-filter: var(--glass-blur-sm);
}

.tag-blue { background: rgba(219,234,254,0.70); color: var(--blue-bright); border: 1px solid rgba(59,130,246,0.20); }
.tag-purple { background: rgba(237,233,254,0.70); color: var(--purple-dark); border: 1px solid rgba(167,139,250,0.25); }
.tag-cyan { background: rgba(207,250,254,0.70); color: #0891B2; border: 1px solid rgba(6,182,212,0.20); }
.tag-green { background: rgba(209,250,229,0.70); color: #059669; border: 1px solid rgba(16,185,129,0.20); }

/* ── Pros Cons ────────────────────────────────────────────── */
.pros-cons {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin: 24px 0;
}

.pros-list, .cons-list {
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur-sm);
  -webkit-backdrop-filter: var(--glass-blur-sm);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: 20px;
  box-shadow: var(--glass-shadow), var(--glass-inner);
}

.pros-list { border-top: 3px solid var(--success); }
.cons-list { border-top: 3px solid rgba(239,68,68,0.60); }

.pros-list h4 { color: var(--success); font-size: .9rem; font-weight: 700; margin-bottom: 12px; }
.cons-list h4 { color: var(--danger); font-size: .9rem; font-weight: 700; margin-bottom: 12px; }

.pros-list ul li, .cons-list ul li {
  font-size: .88rem;
  color: var(--text-secondary);
  padding: 5px 0;
  border-bottom: 1px solid rgba(148,163,184,0.10);
  line-height: 1.6;
}

.pros-list ul li:last-child, .cons-list ul li:last-child { border-bottom: none; }

/* ── Key Takeaways ────────────────────────────────────────── */
.gsyc-takeaways {
  background: linear-gradient(135deg, rgba(59,130,246,0.06) 0%, rgba(167,139,250,0.05) 100%);
  backdrop-filter: var(--glass-blur-sm);
  -webkit-backdrop-filter: var(--glass-blur-sm);
  border: 1px solid rgba(59,130,246,0.18);
  border-radius: var(--radius-lg);
  padding: 28px;
  margin: 32px 0;
  box-shadow: 0 4px 20px rgba(59,130,246,0.08), var(--glass-inner);
}

.tk-label {
  font-size: .78rem;
  font-weight: 800;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--blue-primary);
  margin-bottom: 14px;
}

.gsyc-takeaways ul { display: flex; flex-direction: column; gap: 10px; }
.gsyc-takeaways ul li {
  display: flex;
  gap: 10px;
  font-size: .92rem;
  color: var(--text-secondary);
  line-height: 1.6;
}
.gsyc-takeaways ul li::before {
  content: '✦';
  color: var(--blue-primary);
  flex-shrink: 0;
  margin-top: 1px;
  font-size: .8rem;
}

/* ── Related Articles ─────────────────────────────────────── */
.gsyc-related { margin: 40px 0 0; }

.related-title {
  font-size: .82rem;
  font-weight: 700;
  letter-spacing: .06em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 14px;
  padding-bottom: 10px;
  border-bottom: 1px solid rgba(148,163,184,0.20);
}

.related-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; }

.related-card {
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur-sm);
  -webkit-backdrop-filter: var(--glass-blur-sm);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: 14px 16px;
  transition: all var(--dur-fast);
  box-shadow: 0 2px 8px rgba(59,130,246,0.06), var(--glass-inner);
  text-decoration: none;
}

.related-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(59,130,246,0.12), var(--glass-inner);
  background: var(--glass-bg-strong);
}

.related-tag {
  font-size: .7rem;
  font-weight: 700;
  color: var(--blue-primary);
  margin-bottom: 5px;
  text-transform: uppercase;
  letter-spacing: .05em;
}

.related-card-title {
  font-size: .85rem;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.4;
}

/* ── Prose (Article Body) ─────────────────────────────────── */
.prose { color: var(--text-primary); }

.prose h2 {
  font-size: 1.45rem;
  font-weight: 800;
  color: var(--text-primary);
  margin: 40px 0 16px;
  padding-bottom: 10px;
  border-bottom: 1px solid rgba(148,163,184,0.15);
  letter-spacing: -0.02em;
  line-height: 1.3;
  position: relative;
}

.prose h2::before {
  content: '';
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 60px;
  height: 2px;
  background: var(--grad-brand);
  border-radius: 1px;
}

.prose h3 {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin: 28px 0 12px;
  letter-spacing: -0.01em;
}

.prose p {
  font-size: .97rem;
  line-height: 1.85;
  color: var(--text-secondary);
  margin-bottom: 16px;
}

.prose ul, .prose ol {
  margin: 16px 0;
  padding-left: 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.prose ul li {
  display: flex;
  gap: 10px;
  font-size: .95rem;
  color: var(--text-secondary);
  line-height: 1.7;
  list-style: none;
}

.prose ul li::before {
  content: '·';
  color: var(--blue-primary);
  font-size: 1.2rem;
  line-height: 1.5;
  flex-shrink: 0;
  font-weight: 700;
}

.prose ol { counter-reset: item; }
.prose ol li {
  counter-increment: item;
  font-size: .95rem;
  color: var(--text-secondary);
  line-height: 1.7;
  display: flex;
  gap: 10px;
}
.prose ol li::before {
  content: counter(item) '.';
  color: var(--blue-primary);
  font-weight: 700;
  flex-shrink: 0;
  min-width: 20px;
}

.prose strong { font-weight: 700; color: var(--text-primary); }
.prose code {
  background: rgba(59,130,246,0.08);
  border: 1px solid rgba(59,130,246,0.15);
  border-radius: 4px;
  padding: 2px 7px;
  font-size: .88em;
  color: var(--blue-bright);
  font-family: 'SFMono-Regular', Consolas, monospace;
}

.prose table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  margin: 24px 0;
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur-sm);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--glass-shadow);
}

.prose th {
  background: rgba(59,130,246,0.08);
  padding: 12px 16px;
  font-size: .85rem;
  font-weight: 700;
  color: var(--text-primary);
  text-align: left;
  border-bottom: 1px solid rgba(148,163,184,0.15);
}

.prose td {
  padding: 10px 16px;
  font-size: .88rem;
  color: var(--text-secondary);
  border-bottom: 1px solid rgba(148,163,184,0.10);
}

.prose tr:last-child td { border-bottom: none; }
.prose tr:hover td { background: rgba(59,130,246,0.03); }

/* ── Footer ───────────────────────────────────────────────── */
.gsyc-footer {
  background: var(--bg-footer);
  color: rgba(255,255,255,0.85);
  padding: var(--space-2xl) 0 0;
  margin-top: var(--space-2xl);
  position: relative;
  overflow: hidden;
}

.gsyc-footer::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(59,130,246,0.4), rgba(167,139,250,0.4), transparent);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.6fr 1fr 1fr 1fr;
  gap: 40px;
  padding-bottom: var(--space-xl);
  border-bottom: 1px solid rgba(255,255,255,0.08);
}

.footer-brand p {
  font-size: .88rem;
  color: rgba(255,255,255,0.55);
  line-height: 1.75;
  margin: 14px 0 20px;
  max-width: 260px;
}

.footer-brand .nav-logo-text {
  -webkit-text-fill-color: #fff;
  background: none;
  color: #fff;
}

.footer-col h4 {
  font-size: .8rem;
  font-weight: 700;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.45);
  margin-bottom: 16px;
}

.footer-col ul { display: flex; flex-direction: column; gap: 8px; }

.footer-col ul li a {
  font-size: .88rem;
  color: rgba(255,255,255,0.60);
  transition: color var(--dur-fast);
  text-decoration: none;
}

.footer-col ul li a:hover { color: #fff; }

.footer-disclaimer {
  font-size: .8rem;
  color: rgba(255,255,255,0.35);
  line-height: 1.7;
  padding: var(--space-md) 0;
  border-bottom: 1px solid rgba(255,255,255,0.06);
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--space-md) 0;
  font-size: .8rem;
  color: rgba(255,255,255,0.30);
  flex-wrap: wrap;
  gap: 12px;
}

.footer-bottom a { color: rgba(255,255,255,0.35); transition: color var(--dur-fast); }
.footer-bottom a:hover { color: rgba(255,255,255,0.70); }

/* ── Back to Top ──────────────────────────────────────────── */
.back-to-top {
  position: fixed;
  bottom: 28px;
  right: 28px;
  width: 44px;
  height: 44px;
  background: var(--glass-bg-strong);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border: 1px solid var(--glass-border);
  border-radius: 50%;
  color: var(--blue-primary);
  font-size: 1.1rem;
  font-weight: 700;
  cursor: pointer;
  box-shadow: var(--glass-shadow);
  transition: all var(--dur-base) var(--ease-out);
  opacity: 0;
  transform: translateY(16px);
  z-index: 100;
}

.back-to-top.visible {
  opacity: 1;
  transform: translateY(0);
}

.back-to-top:hover {
  background: var(--blue-primary);
  color: #fff;
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(59,130,246,0.35);
}

/* ── Utility Classes ──────────────────────────────────────── */
.text-center { text-align: center; }
.flex { display: flex; }
.flex-col { flex-direction: column; }
.items-center { align-items: center; }
.justify-center { justify-content: center; }
.gap-8 { gap: 8px; }
.gap-16 { gap: 16px; }
.gap-24 { gap: 24px; }
.mt-8 { margin-top: 8px; }
.mt-16 { margin-top: 16px; }
.mb-16 { margin-bottom: 16px; }
.mb-24 { margin-bottom: 24px; }

/* ── Glass Panel (generic) ────────────────────────────────── */
.glass-panel {
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--glass-shadow), var(--glass-inner);
}

/* ── Feature Highlight ────────────────────────────────────── */
.gsyc-highlight {
  display: flex;
  gap: 16px;
  align-items: flex-start;
  padding: 16px 20px;
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur-sm);
  -webkit-backdrop-filter: var(--glass-blur-sm);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  box-shadow: 0 2px 10px rgba(59,130,246,0.06), var(--glass-inner);
}

.highlight-icon { font-size: 1.4rem; flex-shrink: 0; }
.highlight-body { flex: 1; }
.highlight-title { font-weight: 700; color: var(--text-primary); font-size: .95rem; margin-bottom: 4px; }
.highlight-desc { font-size: .88rem; color: var(--text-secondary); line-height: 1.7; }

/* ── Comparison Table ─────────────────────────────────────── */
.gsyc-compare-table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur-sm);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--glass-shadow);
  margin: 24px 0;
}

.gsyc-compare-table th {
  background: rgba(59,130,246,0.07);
  padding: 14px 18px;
  font-size: .85rem;
  font-weight: 700;
  color: var(--text-primary);
  text-align: left;
  border-bottom: 1px solid rgba(148,163,184,0.15);
}

.gsyc-compare-table td {
  padding: 12px 18px;
  font-size: .9rem;
  color: var(--text-secondary);
  border-bottom: 1px solid rgba(148,163,184,0.08);
}

.gsyc-compare-table tr:last-child td { border-bottom: none; }
.gsyc-compare-table tr:hover td { background: rgba(59,130,246,0.03); }

/* ── CTA Section ──────────────────────────────────────────── */
.gsyc-cta-section {
  background: linear-gradient(135deg, rgba(59,130,246,0.08) 0%, rgba(167,139,250,0.07) 100%);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border: 1px solid rgba(59,130,246,0.18);
  border-radius: var(--radius-xl);
  padding: 56px 40px;
  text-align: center;
  position: relative;
  overflow: hidden;
  box-shadow: 0 8px 40px rgba(59,130,246,0.10), var(--glass-inner);
}

.gsyc-cta-section::before {
  content: '';
  position: absolute;
  width: 300px;
  height: 300px;
  top: -100px;
  right: -80px;
  background: radial-gradient(circle, rgba(167,139,250,0.15) 0%, transparent 70%);
  pointer-events: none;
}

.gsyc-cta-section::after {
  content: '';
  position: absolute;
  width: 200px;
  height: 200px;
  bottom: -60px;
  left: -40px;
  background: radial-gradient(circle, rgba(59,130,246,0.12) 0%, transparent 70%);
  pointer-events: none;
}

/* ── Section with glass bg ────────────────────────────────── */
.section-glass {
  background: rgba(255,255,255,0.30);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-top: 1px solid rgba(255,255,255,0.65);
  border-bottom: 1px solid rgba(255,255,255,0.65);
}

/* ── Checklist ────────────────────────────────────────────── */
.gsyc-checklist {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin: 20px 0;
}

.gsyc-checklist-item {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  padding: 12px 16px;
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur-sm);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  font-size: .92rem;
  color: var(--text-secondary);
  box-shadow: 0 2px 8px rgba(59,130,246,0.05), var(--glass-inner);
}

.gsyc-checklist-item::before {
  content: '✓';
  color: var(--success);
  font-weight: 700;
  flex-shrink: 0;
}

/* ── Animations ───────────────────────────────────────────── */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(24px); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50%       { transform: translateY(-8px); }
}

@keyframes shimmer {
  0%   { background-position: -200% center; }
  100% { background-position:  200% center; }
}

.animate-fade-up { animation: fadeUp .6s var(--ease-out) both; }
.animate-fade-in { animation: fadeIn .5s ease both; }
.animate-float   { animation: float 4s ease-in-out infinite; }

/* ── Responsive ───────────────────────────────────────────── */
@media (max-width: 1024px) {
  .article-layout { grid-template-columns: 1fr; }
  .article-sidebar { position: static; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  :root { --nav-h: 64px; }
  .container { padding: 0 16px; }

  .nav-links { display: none; }
  .nav-links.open {
    display: flex;
    flex-direction: column;
    position: fixed;
    top: var(--nav-h);
    left: 0;
    right: 0;
    background: rgba(242,246,252,0.95);
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    padding: 16px;
    border-bottom: 1px solid rgba(255,255,255,0.80);
    box-shadow: 0 8px 24px rgba(59,130,246,0.10);
    z-index: 100;
    gap: 4px;
  }

  .nav-toggle { display: flex; }

  .nav-cta {
    display: none;
  }

  .gsyc-hero { padding-top: calc(var(--nav-h) + 40px); padding-bottom: 60px; }
  .hero-title { font-size: 2rem; }

  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .grid-auto { grid-template-columns: 1fr; }
  .pros-cons { grid-template-columns: 1fr; }
  .related-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: 28px; }

  .gsyc-cta-section { padding: 36px 20px; }

  .plan-card.featured { transform: scale(1); }
}

@media (max-width: 480px) {
  .hero-title { font-size: 1.75rem; }
  .section { padding: var(--space-2xl) 0; }
  .gsyc-card { padding: 20px; }
  .gsyc-toc { display: none; }
  .back-to-top { bottom: 16px; right: 16px; }
}

/* ── Print ────────────────────────────────────────────────── */
@media print {
  .gsyc-nav, .back-to-top, .reading-progress { display: none; }
  body { background: #fff; color: #000; }
  a { color: #000; }
}

.flex-center { display:flex; justify-content:center; align-items:center; flex-wrap:wrap; }