/* ==========================================================================
   泡芙云 PAOFU CLOUD - DESIGN SYSTEM & STYLESHEET
   Domain: pfy.lol
   ========================================================================== */

/* 1. Design Tokens & Color Variables */
:root {
  --bg-primary: #ffffff;
  --bg-secondary: #f8fafc;
  --bg-tertiary: #f1f5f9;
  --bg-card: #ffffff;
  --bg-glass: rgba(255, 255, 255, 0.88);

  --text-main: #1e293b;
  --text-muted: #64748b;
  --text-light: #94a3b8;

  --primary: #00bcd4;
  --primary-hover: #00acc1;
  --primary-light: rgba(0, 188, 212, 0.1);
  --primary-glow: rgba(0, 188, 212, 0.35);

  --cyan-gradient: linear-gradient(135deg, #00d2ff 0%, #0084ff 100%);
  --cyan-badge-bg: #e0f7fa;

  --border-color: #e2e8f0;
  --border-card: #e2e8f0;

  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 10px 30px rgba(0, 188, 212, 0.08);
  --shadow-lg: 0 20px 40px rgba(0, 0, 0, 0.08);
  --shadow-featured: 0 15px 35px rgba(0, 188, 212, 0.25);

  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-full: 9999px;

  --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Dark Theme Variables */
[data-theme="dark"] {
  --bg-primary: #0b0f19;
  --bg-secondary: #111827;
  --bg-tertiary: #1f2937;
  --bg-card: #161f30;
  --bg-glass: rgba(17, 24, 39, 0.9);

  --text-main: #f3f4f6;
  --text-muted: #9ca3af;
  --text-light: #6b7280;

  --border-color: #2a364f;
  --border-card: #1e2d4a;

  --shadow-sm: 0 2px 10px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 10px 30px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 20px 50px rgba(0, 0, 0, 0.5);
  --shadow-featured: 0 15px 40px rgba(0, 210, 255, 0.3);

  --cyan-badge-bg: rgba(0, 188, 212, 0.15);
}

/* Respect Motion Preferences */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* 2. Reset & General Setup */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: 'Plus Jakarta Sans', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-main);
  line-height: 1.6;
  transition: background-color var(--transition-normal), color var(--transition-normal);
  overflow-x: hidden;
}

.container {
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 24px;
}

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

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

.text-center { text-align: center; }
.font-bold { font-weight: 800; }
.m-t-1 { margin-top: 12px; }
.m-t-2 { margin-top: 24px; }

/* 3. Header & Navigation */
.navbar {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: var(--bg-glass);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-color);
  transition: all var(--transition-normal);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1280px;
  margin: 0 auto;
  padding: 14px 24px;
}

/* Enhanced Logo Styling */
.brand-logo {
  display: flex;
  align-items: center;
  gap: 12px;
}

.logo-wrapper {
  position: relative;
  width: 44px;
  height: 44px;
  border-radius: var(--radius-sm);
  overflow: hidden;
  box-shadow: 0 4px 14px rgba(0, 188, 212, 0.3);
  transition: transform var(--transition-fast);
}

.brand-logo:hover .logo-wrapper {
  transform: scale(1.06) rotate(-2deg);
}

.logo-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.logo-glow {
  position: absolute;
  inset: 0;
  background: radial-gradient(circle, rgba(0, 210, 255, 0.4) 0%, transparent 70%);
  opacity: 0.6;
  pointer-events: none;
}

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

.brand-name {
  font-size: 1.25rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--text-main);
  background: var(--cyan-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.brand-badge {
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--text-muted);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-item {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-muted);
  transition: color var(--transition-fast);
  position: relative;
  padding: 6px 0;
}

.nav-item:hover, .nav-item.active {
  color: var(--primary);
  font-weight: 600;
}

.nav-item.active::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 2.5px;
  background: var(--primary);
  border-radius: var(--radius-full);
}

.nav-highlight {
  color: var(--primary);
  font-weight: 700;
}

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

/* Language Switcher Pill */
.lang-switcher {
  display: flex;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  padding: 3px;
}

.lang-opt {
  padding: 4px 10px;
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text-muted);
  border-radius: var(--radius-full);
  transition: all var(--transition-fast);
}

.lang-opt.active {
  background: var(--primary);
  color: #ffffff;
  box-shadow: 0 2px 8px rgba(0, 188, 212, 0.4);
}

/* Theme Toggle Button */
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  border-radius: var(--radius-full);
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  transition: all var(--transition-fast);
}

.theme-toggle:hover {
  transform: rotate(15deg) scale(1.05);
  border-color: var(--primary);
}

.sun-icon { display: block; width: 18px; height: 18px; color: #f59e0b; }
.moon-icon { display: none; width: 18px; height: 18px; color: #60a5fa; }

[data-theme="dark"] .sun-icon { display: none; }
[data-theme="dark"] .moon-icon { display: block; }

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 20px;
  font-size: 0.92rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  transition: all var(--transition-fast);
  white-space: nowrap;
  min-height: 44px;
}

.btn-lg {
  padding: 14px 28px;
  font-size: 1rem;
  border-radius: var(--radius-full);
  min-height: 48px;
}

.btn-primary {
  background: var(--cyan-gradient);
  color: #ffffff;
  box-shadow: 0 4px 15px rgba(0, 188, 212, 0.35);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(0, 188, 212, 0.5);
}

.btn-secondary {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  box-shadow: var(--shadow-sm);
}

.btn-secondary:hover {
  border-color: var(--primary);
  color: var(--primary);
  transform: translateY(-2px);
}

.btn-outline {
  border: 1px solid var(--border-color);
  background: var(--bg-card);
  color: var(--text-main);
}

.btn-outline:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.btn-outline-cyan {
  border: 1.5px solid var(--primary);
  color: var(--primary);
  background: transparent;
}

.btn-outline-cyan:hover {
  background: var(--primary);
  color: #ffffff;
  box-shadow: 0 4px 15px rgba(0, 188, 212, 0.3);
}

.btn-full { width: 100%; }

/* 4. Side Chapter Navigation Arrows (Chapter Arrows Requirement) */
.chapter-nav-arrows {
  position: fixed;
  right: 20px;
  top: 50%;
  transform: translateY(-50%);
  z-index: 999;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  background: var(--bg-glass);
  backdrop-filter: blur(12px);
  padding: 8px;
  border-radius: var(--radius-full);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-md);
  transition: all var(--transition-normal);
}

.arrow-btn {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
}

.arrow-btn:hover:not(:disabled) {
  background: var(--primary);
  color: #ffffff;
  border-color: var(--primary);
  transform: scale(1.1);
}

.arrow-btn:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

.chapter-indicator {
  font-size: 0.72rem;
  font-weight: 800;
  color: var(--text-muted);
  padding: 2px 6px;
  letter-spacing: 0.05em;
}

/* 5. Hero Section */
.hero-section {
  padding: 80px 0 60px;
  position: relative;
  background: radial-gradient(circle at 10% 20%, rgba(0, 188, 212, 0.05) 0%, transparent 50%);
}

.hero-container {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  align-items: center;
  gap: 48px;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  background: var(--cyan-badge-bg);
  color: var(--primary);
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 700;
  margin-bottom: 24px;
  border: 1px solid rgba(0, 188, 212, 0.2);
}

.badge-dot {
  width: 8px;
  height: 8px;
  background: var(--primary);
  border-radius: 50%;
  box-shadow: 0 0 10px var(--primary);
  animation: pulse 1.8s infinite;
}

@keyframes pulse {
  0%, 100% { transform: scale(1); opacity: 1; }
  50% { transform: scale(1.4); opacity: 0.6; }
}

.hero-title {
  font-size: 3.2rem;
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 20px;
  letter-spacing: -0.03em;
}

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

.hero-subtitle {
  font-size: 1.1rem;
  color: var(--text-muted);
  margin-bottom: 28px;
  max-width: 600px;
  line-height: 1.7;
}

.hero-bullets {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 14px;
  margin-bottom: 36px;
}

.hero-bullets li {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-main);
}

.check-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 22px;
  height: 22px;
  background: var(--primary);
  color: #ffffff;
  border-radius: 50%;
  flex-shrink: 0;
  box-shadow: 0 2px 8px rgba(0, 188, 212, 0.4);
}

.check-icon svg { width: 13px; height: 13px; }

.hero-cta-group {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 40px;
}

.hero-platforms {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.platform-label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-light);
}

.platform-icons {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.platform-chip {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-muted);
  transition: all var(--transition-fast);
}

.platform-chip:hover {
  border-color: var(--primary);
  color: var(--primary);
  transform: translateY(-2px);
}

.hero-visual {
  position: relative;
  display: flex;
  justify-content: center;
}

.illustration-frame {
  position: relative;
  width: 100%;
  max-width: 520px;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--border-color);
  background: var(--bg-card);
}

.hero-img {
  width: 100%;
  height: auto;
  display: block;
}

.floating-badge {
  position: absolute;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 18px;
  background: var(--bg-glass);
  backdrop-filter: blur(12px);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-md);
  animation: float 4s ease-in-out infinite alternate;
}

.badge-top-right { top: 20px; right: -10px; }
.badge-bottom-left { bottom: 24px; left: -10px; animation-delay: -2s; }

@keyframes float {
  0% { transform: translateY(0); }
  100% { transform: translateY(-10px); }
}

.badge-icon {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
}

.green-glow { background: rgba(16, 185, 129, 0.15); }
.cyan-glow { background: rgba(0, 188, 212, 0.15); }

.badge-info { display: flex; flex-direction: column; }
.badge-info .val { font-size: 1rem; font-weight: 800; color: var(--text-main); line-height: 1.2; }
.badge-info .lbl { font-size: 0.72rem; color: var(--text-muted); }

/* 6. Pricing Section */
.pricing-section {
  padding: 100px 0;
  background: var(--bg-secondary);
}

.section-header { margin-bottom: 50px; }
.section-subtitle { font-size: 0.85rem; font-weight: 800; color: var(--primary); letter-spacing: 0.1em; text-transform: uppercase; margin-bottom: 8px; display: block; }
.section-title { font-size: 2.5rem; font-weight: 800; color: var(--text-main); margin-bottom: 12px; letter-spacing: -0.02em; }
.section-desc { font-size: 1.05rem; color: var(--text-muted); max-width: 640px; margin: 0 auto; }

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 30px;
  align-items: stretch;
  margin-bottom: 60px;
}

.pricing-card {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-lg);
  padding: 36px 28px;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: all var(--transition-normal);
  box-shadow: var(--shadow-sm);
}

.pricing-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-md);
  border-color: var(--primary);
}

.pricing-card.featured {
  border: 2.5px solid var(--primary);
  box-shadow: var(--shadow-featured);
  transform: scale(1.03);
  z-index: 2;
}

.pricing-card.featured:hover { transform: scale(1.05) translateY(-6px); }

.featured-ribbon {
  position: absolute;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--cyan-gradient);
  color: #ffffff;
  font-size: 0.8rem;
  font-weight: 800;
  padding: 4px 18px;
  border-radius: var(--radius-full);
  box-shadow: 0 4px 10px rgba(0, 188, 212, 0.4);
}

.card-header { margin-bottom: 24px; text-align: center; }
.plan-tag { font-size: 0.8rem; font-weight: 700; color: var(--primary); text-transform: uppercase; }
.plan-name { font-size: 1.5rem; font-weight: 800; margin: 8px 0 12px; }

.plan-price { display: flex; align-items: baseline; justify-content: center; gap: 4px; }
.plan-price .currency { font-size: 1.5rem; font-weight: 700; color: var(--text-main); }
.plan-price .amount { font-size: 3.2rem; font-weight: 900; line-height: 1; color: var(--text-main); }
.plan-price .period { font-size: 0.95rem; color: var(--text-muted); }

.discount-badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  margin-top: 10px;
  padding: 3px 10px;
  background: rgba(16, 185, 129, 0.12);
  color: #10b981;
  font-size: 0.82rem;
  font-weight: 700;
  border-radius: var(--radius-full);
}

.card-body { flex: 1; margin-bottom: 28px; }

.plan-features { list-style: none; display: flex; flex-direction: column; gap: 14px; }
.plan-features li { font-size: 0.92rem; color: var(--text-main); display: flex; align-items: center; gap: 10px; }
.plan-features .check { color: var(--primary); font-weight: 800; }

.shadow-glow { box-shadow: 0 8px 20px rgba(0, 188, 212, 0.4); }

/* Comparison Table */
.table-wrapper {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-lg);
  padding: 36px;
  box-shadow: var(--shadow-sm);
}

.table-header-title { margin-bottom: 24px; }
.table-header-title h3 { font-size: 1.5rem; font-weight: 800; }
.table-header-title p { color: var(--text-muted); font-size: 0.9rem; }

.table-responsive { overflow-x: auto; }
.comparison-table { width: 100%; border-collapse: collapse; text-align: left; }
.comparison-table th, .comparison-table td { padding: 16px 20px; border-bottom: 1px solid var(--border-color); font-size: 0.92rem; }
.comparison-table th { font-size: 1rem; font-weight: 800; color: var(--text-main); background: var(--bg-tertiary); }
.comparison-table .feature-col { width: 28%; }
.feature-label { font-weight: 700; color: var(--text-main); }
.highlight-col { background: rgba(0, 188, 212, 0.05); font-weight: 700; }
.val-active { color: var(--primary); }
.text-link { color: var(--primary); text-decoration: underline; }
.checkmark { color: #10b981; font-weight: 800; }
.cross { color: #ef4444; font-weight: 800; }

/* 7. Product Features Section */
.features-section { padding: 100px 0; }
.features-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 30px; margin-bottom: 50px; }

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-md);
  padding: 30px;
  transition: all var(--transition-normal);
}

.feature-card:hover {
  transform: translateY(-5px);
  border-color: var(--primary);
  box-shadow: var(--shadow-md);
}

.feature-icon {
  width: 52px;
  height: 52px;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
}

.feature-icon svg { width: 26px; height: 26px; }
.feature-icon.cyan { background: rgba(0, 188, 212, 0.12); color: #00bcd4; }
.feature-icon.blue { background: rgba(59, 130, 246, 0.12); color: #3b82f6; }
.feature-icon.purple { background: rgba(168, 85, 247, 0.12); color: #a855f7; }
.feature-icon.green { background: rgba(16, 185, 129, 0.12); color: #10b981; }
.feature-icon.orange { background: rgba(249, 115, 22, 0.12); color: #f97316; }
.feature-icon.pink { background: rgba(236, 72, 153, 0.12); color: #ec4899; }

.feature-card h3 { font-size: 1.2rem; font-weight: 800; margin-bottom: 10px; }
.feature-card p { color: var(--text-muted); font-size: 0.92rem; line-height: 1.6; }

/* Service Support Box */
.service-support-box {
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 32px;
  text-align: center;
}

.support-title { font-size: 1.3rem; font-weight: 800; margin-bottom: 8px; }
.support-intro { color: var(--text-muted); font-size: 0.95rem; max-width: 720px; margin: 0 auto 20px; }

.support-chips { display: flex; flex-wrap: wrap; justify-content: center; gap: 12px; }
.chip-item {
  padding: 8px 18px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--text-main);
  box-shadow: var(--shadow-sm);
}

/* 8. FAQ Accordion Section */
.faq-section { padding: 80px 0; background: var(--bg-secondary); }
.faq-accordion { max-width: 800px; margin: 0 auto; display: flex; flex-direction: column; gap: 16px; }

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: border-color var(--transition-fast);
}

.faq-item.active { border-color: var(--primary); }
.faq-question { width: 100%; padding: 20px 24px; display: flex; align-items: center; justify-content: space-between; font-size: 1.05rem; font-weight: 700; color: var(--text-main); text-align: left; }
.faq-icon { font-size: 1.4rem; font-weight: 400; color: var(--primary); transition: transform var(--transition-normal); }
.faq-item.active .faq-icon { transform: rotate(45deg); }
.faq-answer { max-height: 0; overflow: hidden; transition: max-height 0.3s ease, padding 0.3s ease; padding: 0 24px; }
.faq-item.active .faq-answer { max-height: 200px; padding: 0 24px 20px 24px; }
.faq-answer p { color: var(--text-muted); font-size: 0.95rem; line-height: 1.7; }

/* 9. Articles Preview Grid */
.articles-preview-section { padding: 100px 0; }
.articles-preview-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 28px; }

.article-preview-card {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-md);
  padding: 28px;
  display: flex;
  flex-direction: column;
  transition: all var(--transition-normal);
}

.article-preview-card:hover {
  transform: translateY(-5px);
  border-color: var(--primary);
  box-shadow: var(--shadow-md);
}

.card-date { font-size: 0.8rem; font-weight: 600; color: var(--text-light); margin-bottom: 10px; }
.article-preview-card h3 { font-size: 1.15rem; font-weight: 800; margin-bottom: 10px; line-height: 1.4; }
.article-preview-card p { color: var(--text-muted); font-size: 0.9rem; margin-bottom: 20px; flex: 1; }
.read-more-link { font-size: 0.9rem; font-weight: 700; color: var(--primary); }

/* 10. Support Banner */
.support-banner { padding: 60px 0 100px; }
.banner-card {
  background: var(--cyan-gradient);
  border-radius: var(--radius-lg);
  padding: 48px;
  color: #ffffff;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 30px;
  box-shadow: 0 15px 40px rgba(0, 188, 212, 0.35);
}

.banner-content h2 { font-size: 1.8rem; font-weight: 800; margin-bottom: 8px; }
.banner-content p { opacity: 0.9; font-size: 1rem; }
.banner-actions { display: flex; gap: 14px; flex-shrink: 0; }

.btn-outline-white { border: 1.5px solid rgba(255, 255, 255, 0.8); color: #ffffff; }
.btn-outline-white:hover { background: #ffffff; color: var(--primary); }

/* 11. Footer */
.footer { background: var(--bg-secondary); border-top: 1px solid var(--border-color); padding: 60px 0 30px; }
.footer-container { display: flex; justify-content: space-between; gap: 40px; margin-bottom: 40px; }
.logo-img-sm { width: 32px; height: 32px; border-radius: 6px; }
.footer-brand .brand-logo { margin-bottom: 14px; }
.footer-desc { max-width: 360px; color: var(--text-muted); font-size: 0.9rem; }
.footer-links { display: flex; gap: 60px; }
.footer-col { display: flex; flex-direction: column; gap: 12px; }
.footer-col h4 { font-size: 0.95rem; font-weight: 800; margin-bottom: 6px; }
.footer-col a { color: var(--text-muted); font-size: 0.88rem; transition: color var(--transition-fast); }
.footer-col a:hover { color: var(--primary); }
.footer-bottom { border-top: 1px solid var(--border-color); padding-top: 24px; color: var(--text-light); font-size: 0.85rem; }

/* 12. Article Subpage Styles */
.article-detail-container { max-width: 860px; margin: 40px auto 80px; padding: 0 24px; }
.breadcrumb { display: flex; align-items: center; gap: 8px; font-size: 0.88rem; color: var(--text-muted); margin-bottom: 24px; }
.breadcrumb a { color: var(--primary); font-weight: 600; }

.article-header { margin-bottom: 36px; border-bottom: 1px solid var(--border-color); padding-bottom: 24px; }
.article-title { font-size: 2.4rem; font-weight: 800; line-height: 1.3; margin-bottom: 16px; }
.article-meta { display: flex; align-items: center; gap: 16px; font-size: 0.88rem; color: var(--text-muted); }

.article-body { font-size: 1.05rem; line-height: 1.85; color: var(--text-main); }
.article-body h2 { font-size: 1.6rem; font-weight: 800; margin: 36px 0 16px; border-left: 4px solid var(--primary); padding-left: 12px; }
.article-body h3 { font-size: 1.25rem; font-weight: 700; margin: 24px 0 12px; }
.article-body p { margin-bottom: 20px; }
.article-body ul, .article-body ol { margin: 0 0 20px 24px; }
.article-body li { margin-bottom: 8px; }

.promo-callout {
  background: var(--cyan-badge-bg);
  border: 1px solid rgba(0, 188, 212, 0.3);
  border-radius: var(--radius-md);
  padding: 24px;
  margin: 32px 0;
}

.promo-callout h4 { font-size: 1.2rem; font-weight: 800; color: var(--primary); margin-bottom: 8px; }
.promo-callout p { color: var(--text-main); font-size: 0.95rem; margin-bottom: 16px; }

/* 13. Responsive Breakpoints */
@media (max-width: 1024px) {
  .hero-container { grid-template-columns: 1fr; text-align: center; }
  .hero-subtitle { margin: 0 auto 28px; }
  .hero-bullets { align-items: center; }
  .hero-cta-group { justify-content: center; }
  .hero-platforms { align-items: center; }
  .pricing-grid, .features-grid, .articles-preview-grid { grid-template-columns: 1fr; }
  .pricing-card.featured { transform: scale(1); }
  .banner-card { flex-direction: column; text-align: center; }
}

@media (max-width: 768px) {
  .nav-links { display: none; }
  .hero-title { font-size: 2.2rem; }
  .table-responsive { overflow-x: scroll; }
  .chapter-nav-arrows { right: 8px; padding: 4px; }
  .arrow-btn { width: 32px; height: 32px; }
  .chapter-indicator { font-size: 0.65rem; }
}