/* ==========================================================================
   HuaCloud 花云 Design System & Stylesheet (v2.1 Light Theme)
   ========================================================================== */

:root {
  /* Color Palette - Light Theme */
  --color-bg: #f8fafc;
  --color-surface: #ffffff;
  --color-surface-hover: #f1f5f9;
  --color-border: #e2e8f0;
  --color-border-accent: rgba(79, 70, 229, 0.25);
  
  --color-text: #0f172a;
  --color-text-muted: #64748b;
  --color-text-light: #94a3b8;
  
  --color-accent: #4f46e5;
  --color-accent-hover: #4338ca;
  --color-accent-light: rgba(79, 70, 229, 0.08);
  --color-cyan: #06b6d4;
  --color-cyan-light: rgba(6, 182, 212, 0.1);
  --color-success: #10b981;
  --color-success-light: rgba(16, 185, 129, 0.1);
  --color-danger: #ef4444;

  /* Spacing & Radius */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-xl: 24px;
  
  /* Shadows & Elevation */
  --elevation-1: 0 1px 3px rgba(15, 23, 42, 0.05), 0 1px 2px rgba(15, 23, 42, 0.03);
  --elevation-2: 0 4px 12px rgba(15, 23, 42, 0.06), 0 1px 3px rgba(15, 23, 42, 0.02);
  --elevation-3: 0 20px 25px -5px rgba(15, 23, 42, 0.08), 0 8px 10px -6px rgba(15, 23, 42, 0.02);

  /* Typography */
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --transition-fast: transform 0.28s cubic-bezier(0.34, 1.56, 0.64, 1), opacity 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}

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

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

body {
  background-color: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-body);
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

/* Mobile Sticky Bar Padding Reserve */
@media (max-width: 768px) {
  body {
    padding-bottom: calc(76px + env(safe-area-inset-bottom));
  }
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
  position: relative;
  z-index: 1;
}

/* Vector Graphic Background Pattern */
.bg-pattern {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 600px;
  z-index: 0;
  pointer-events: none;
  background-image: radial-gradient(circle at 50% 0%, rgba(79, 70, 229, 0.08) 0%, rgba(6, 182, 212, 0.03) 50%, transparent 80%);
}

/* Header & Navigation */
.navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 0;
  border-bottom: 1px solid var(--color-border);
  position: relative;
  z-index: 10;
}

.logo {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--color-text);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 8px;
}

.logo-badge {
  background: var(--color-accent);
  color: #ffffff;
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  font-size: 0.75rem;
  font-weight: 700;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 24px;
}

.nav-links a {
  color: var(--color-text-muted);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.2s ease;
}

.nav-links a:hover,
.nav-links a:focus-visible {
  color: var(--color-accent);
}

.mobile-menu-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  color: var(--color-text);
  cursor: pointer;
  padding: 4px;
}

/* Hero Section */
.hero {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 40px;
  padding: 60px 0 80px;
}

.hero-content {
  flex: 1.1;
}

.status-bar {
  display: inline-flex;
  align-items: center;
  background: var(--color-success-light);
  border: 1px solid rgba(16, 185, 129, 0.2);
  padding: 6px 16px;
  border-radius: 20px;
  color: var(--color-success);
  font-size: 0.9rem;
  font-weight: 600;
  margin-bottom: 24px;
}

.status-dot {
  width: 8px;
  height: 8px;
  background-color: var(--color-success);
  border-radius: 50%;
  margin-right: 8px;
  box-shadow: 0 0 8px var(--color-success);
}

h1 {
  font-size: 3.2rem;
  font-weight: 800;
  line-height: 1.15;
  margin-bottom: 20px;
  color: var(--color-text);
  background: linear-gradient(135deg, #0f172a 0%, #334155 100%);
  color: #0f172a;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

/* Gradient text fallback protection */
@supports not (-webkit-background-clip: text) {
  h1 { color: #0f172a; }
}

.subtitle {
  font-size: 1.1rem;
  color: var(--color-text-muted);
  max-width: 600px;
  margin-bottom: 30px;
  line-height: 1.7;
}

/* Hero Trust Pills */
.hero-trust-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 32px;
}

.trust-pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  padding: 6px 14px;
  border-radius: 20px;
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--color-text);
  box-shadow: var(--elevation-1);
}

/* CTA Group & Buttons */
.hero-cta-group {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 16px;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--color-accent);
  color: #ffffff;
  font-weight: 700;
  font-size: 1.05rem;
  padding: 16px 32px;
  border-radius: var(--radius-md);
  text-decoration: none;
  border: none;
  box-shadow: 0 4px 14px rgba(79, 70, 229, 0.35);
  transition: var(--transition-fast);
  cursor: pointer;
}

.btn-primary:hover,
.btn-primary:focus-visible {
  background: var(--color-accent-hover);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(79, 70, 229, 0.45);
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--color-surface);
  color: var(--color-text);
  font-weight: 600;
  font-size: 1rem;
  padding: 15px 28px;
  border-radius: var(--radius-md);
  text-decoration: none;
  border: 1px solid var(--color-border);
  box-shadow: var(--elevation-1);
  transition: var(--transition-fast);
}

.btn-secondary:hover,
.btn-secondary:focus-visible {
  background: var(--color-surface-hover);
  border-color: var(--color-border-accent);
  color: var(--color-accent);
  transform: translateY(-2px);
}

.trust-microcopy {
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

/* Hero SVG Illustration */
.hero-graphics {
  flex: 0.9;
  display: flex;
  justify-content: center;
  align-items: center;
  position: relative;
}

.hero-svg-container {
  width: 100%;
  max-width: 420px;
  height: auto;
  filter: drop-shadow(0 20px 30px rgba(79, 70, 229, 0.12));
}

/* Sections Base */
.section-title {
  text-align: center;
  font-size: 2.2rem;
  font-weight: 800;
  color: var(--color-text);
  margin-bottom: 12px;
}

.section-subtitle {
  text-align: center;
  font-size: 1.05rem;
  color: var(--color-text-muted);
  margin-bottom: 48px;
}

/* Pricing Section & Promo Banner */
.pricing-section {
  padding: 60px 0 80px;
}

.promo-banner {
  background: linear-gradient(135deg, rgba(79, 70, 229, 0.08) 0%, rgba(6, 182, 212, 0.08) 100%);
  border: 1px solid var(--color-border-accent);
  border-radius: var(--radius-lg);
  padding: 16px 24px;
  text-align: center;
  font-weight: 700;
  color: var(--color-accent);
  font-size: 1.05rem;
  margin-bottom: 40px;
  box-shadow: var(--elevation-1);
}

.promo-code-pill {
  background: var(--color-surface);
  border: 1px dashed var(--color-accent);
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  color: var(--color-text);
  letter-spacing: 0.5px;
  user-select: all;
}

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 32px;
  margin-bottom: 32px;
}

.pricing-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: 40px 32px;
  box-shadow: var(--elevation-2);
  transition: var(--transition-fast);
  position: relative;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.pricing-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--elevation-3);
  border-color: var(--color-border-accent);
}

.pricing-card.popular {
  border: 2px solid var(--color-accent);
  box-shadow: 0 10px 30px rgba(79, 70, 229, 0.12);
}

.popular-badge {
  position: absolute;
  top: 24px;
  right: -36px;
  background: var(--color-accent);
  color: #ffffff;
  padding: 6px 40px;
  font-size: 0.8rem;
  font-weight: 800;
  transform: rotate(45deg);
}

.tier-name {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 12px;
}

.price {
  font-size: 3rem;
  font-weight: 800;
  color: var(--color-text);
  margin-bottom: 24px;
  display: flex;
  align-items: baseline;
}

.price span {
  font-size: 1rem;
  color: var(--color-text-muted);
  font-weight: normal;
  margin-left: 6px;
}

.features-list {
  list-style: none;
  margin-bottom: 32px;
  flex-grow: 1;
}

.features-list li {
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  font-size: 0.95rem;
  color: var(--color-text-muted);
}

.features-list li::before {
  content: "✓";
  color: var(--color-success);
  margin-right: 12px;
  font-weight: bold;
}

.card-refund-pill {
  text-align: center;
  font-size: 0.82rem;
  color: var(--color-text-muted);
  margin-top: 12px;
}

/* Bento Grid Features */
.bento-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-auto-rows: minmax(200px, auto);
  gap: 24px;
  margin-bottom: 80px;
}

.bento-item {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: 32px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  box-shadow: var(--elevation-1);
  transition: var(--transition-fast);
  position: relative;
}

.bento-item:hover {
  transform: translateY(-3px);
  box-shadow: var(--elevation-2);
}

.bento-large {
  grid-column: span 2;
  grid-row: span 2;
  background: linear-gradient(135deg, rgba(79, 70, 229, 0.03) 0%, rgba(255, 255, 255, 1) 100%);
}

.bento-wide {
  grid-column: span 2;
  background: linear-gradient(135deg, rgba(6, 182, 212, 0.03) 0%, rgba(255, 255, 255, 1) 100%);
}

.native-ip-tag {
  position: absolute;
  top: 24px;
  right: 24px;
  background: var(--color-cyan-light);
  color: var(--color-cyan);
  padding: 4px 12px;
  border-radius: var(--radius-sm);
  font-size: 0.8rem;
  font-weight: 700;
}

.bento-icon {
  font-size: 2.5rem;
  margin-bottom: 16px;
}

.bento-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 10px;
}

.bento-desc {
  font-size: 0.95rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}

/* Core Advantages Grid */
.advantages-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
  margin-bottom: 80px;
}

.adv-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: 36px 28px;
  box-shadow: var(--elevation-1);
}

.adv-icon {
  width: 56px;
  height: 56px;
  background: var(--color-accent-light);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.6rem;
  color: var(--color-accent);
  margin-bottom: 20px;
}

.adv-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 12px;
  color: var(--color-text);
}

.adv-desc {
  color: var(--color-text-muted);
  font-size: 0.95rem;
  line-height: 1.65;
}

/* SEO Articles Grid */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 24px;
  margin-bottom: 80px;
}

.article-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 28px;
  text-decoration: none;
  box-shadow: var(--elevation-1);
  transition: var(--transition-fast);
  display: flex;
  flex-direction: column;
}

.article-card:hover,
.article-card:focus-visible {
  transform: translateY(-3px);
  border-color: var(--color-border-accent);
  box-shadow: var(--elevation-2);
}

.article-card h3 {
  color: var(--color-text);
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 10px;
  line-height: 1.4;
}

.article-card p {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  line-height: 1.6;
}

/* FAQ Accordion Section */
.faq-container {
  max-width: 840px;
  margin: 0 auto 80px;
}

.faq-item {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 24px 28px;
  margin-bottom: 16px;
  box-shadow: var(--elevation-1);
}

.faq-q {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--color-text);
  margin-bottom: 10px;
}

.faq-a {
  color: var(--color-text-muted);
  font-size: 0.95rem;
  line-height: 1.65;
}

/* User Reviews Section */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
  margin-bottom: 80px;
}

.review-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 28px;
  box-shadow: var(--elevation-1);
}

.review-stars {
  color: #f59e0b;
  margin-bottom: 12px;
  letter-spacing: 2px;
}

.review-text {
  font-size: 0.95rem;
  color: var(--color-text-muted);
  margin-bottom: 16px;
  font-style: italic;
  line-height: 1.6;
}

.review-author {
  font-weight: 700;
  font-size: 0.9rem;
  color: var(--color-text);
}

/* Footer Section */
footer {
  border-top: 1px solid var(--color-border);
  padding: 48px 0;
  background: var(--color-surface);
  text-align: center;
  margin-top: 60px;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 32px;
  margin-bottom: 20px;
  flex-wrap: wrap;
}

.footer-links a {
  color: var(--color-text-muted);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 500;
  transition: color 0.2s ease;
}

.footer-links a:hover,
.footer-links a:focus-visible {
  color: var(--color-accent);
}

.copyright {
  color: var(--color-text-light);
  font-size: 0.85rem;
  margin-bottom: 16px;
}

.blog-outbound-links {
  font-size: 0.8rem;
  color: var(--color-text-light);
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.blog-outbound-links a {
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color 0.2s ease;
}

.blog-outbound-links a:hover {
  color: var(--color-accent);
}

/* Mobile Sticky CTA Bar (C4) */
.sticky-mobile-bar {
  display: none;
}

@media (max-width: 768px) {
  .sticky-mobile-bar {
    display: flex;
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    z-index: 999;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-top: 1px solid var(--color-border);
    padding: 12px 16px;
    padding-bottom: calc(12px + env(safe-area-inset-bottom));
    box-shadow: 0 -4px 20px rgba(0, 0, 0, 0.08);
    gap: 12px;
    align-items: center;
    justify-content: space-between;
  }

  .sticky-btn-sec {
    flex: 1;
    text-align: center;
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    color: var(--color-text);
    padding: 12px;
    border-radius: var(--radius-md);
    font-weight: 600;
    text-decoration: none;
    font-size: 0.9rem;
  }

  .sticky-btn-pri {
    flex: 1.4;
    text-align: center;
    background: var(--color-accent);
    color: #ffffff;
    padding: 12px;
    border-radius: var(--radius-md);
    font-weight: 700;
    text-decoration: none;
    font-size: 0.95rem;
    box-shadow: 0 4px 12px rgba(79, 70, 229, 0.3);
  }
}

/* Exit-Intent Popup (C5 - Desktop Only) */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(15, 23, 42, 0.6);
  backdrop-filter: blur(6px);
  z-index: 10000;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.25s ease, visibility 0.25s ease;
}

.modal-overlay.active {
  opacity: 1;
  visibility: visible;
}

.modal-container {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: 40px;
  max-width: 480px;
  width: 90%;
  position: relative;
  box-shadow: var(--elevation-3);
  transform: scale(0.95);
  transition: transform 0.25s cubic-bezier(0.34, 1.56, 0.64, 1);
  text-align: center;
}

.modal-overlay.active .modal-container {
  transform: scale(1);
}

.modal-close-btn {
  position: absolute;
  top: 16px;
  right: 16px;
  background: none;
  border: none;
  font-size: 1.5rem;
  color: var(--color-text-muted);
  cursor: pointer;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background-color 0.2s ease;
}

.modal-close-btn:hover,
.modal-close-btn:focus-visible {
  background: var(--color-surface-hover);
  color: var(--color-text);
}

.modal-title {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--color-text);
  margin-bottom: 10px;
}

.modal-desc {
  font-size: 0.95rem;
  color: var(--color-text-muted);
  margin-bottom: 24px;
}

.coupon-box {
  background: var(--color-accent-light);
  border: 2px dashed var(--color-accent);
  border-radius: var(--radius-md);
  padding: 16px;
  margin-bottom: 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.coupon-code {
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--color-accent);
  letter-spacing: 1px;
  user-select: all;
}

.btn-copy {
  background: var(--color-accent);
  color: #ffffff;
  border: none;
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  font-weight: 700;
  font-size: 0.88rem;
  cursor: pointer;
  transition: background-color 0.2s ease;
}

.btn-copy:hover,
.btn-copy:focus-visible {
  background: var(--color-accent-hover);
}

.modal-cta {
  width: 100%;
  margin-bottom: 16px;
}

.modal-trust-row {
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

/* Accessibility Focus States */
a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

/* Responsive Media Queries */
@media (max-width: 992px) {
  .bento-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .advantages-grid {
    grid-template-columns: 1fr;
  }
  .hero {
    flex-direction: column;
    text-align: center;
  }
  .hero-content .subtitle {
    margin-left: auto;
    margin-right: auto;
  }
  .hero-trust-pills {
    justify-content: center;
  }
  .hero-cta-group {
    justify-content: center;
  }
}

@media (max-width: 768px) {
  h1 { font-size: 2.2rem; }
  .section-title { font-size: 1.8rem; }
  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    padding: 20px;
    flex-direction: column;
    gap: 16px;
    box-shadow: var(--elevation-2);
  }
  .nav-links.active {
    display: flex;
  }
  .mobile-menu-toggle {
    display: block;
  }
  .pricing-grid {
    grid-template-columns: 1fr;
  }
  .bento-grid {
    grid-template-columns: 1fr;
    grid-auto-rows: auto;
  }
  .bento-large, .bento-wide {
    grid-column: span 1;
    grid-row: span 1;
  }
  .modal-container {
    padding: 28px 20px;
  }
}

/* Reduced Motion Override */
@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;
  }
}