:root {
  --bg-color: #e0f2fe; 
  --text-main: #0f172a;
  --text-muted: #475569;
  --accent-color: #0284c7; 
  --accent-hover: #0369a1;
  --accent-light: #38bdf8;
  --success-color: #10b981;
  --danger-color: #ef4444;
  --card-bg: rgba(255, 255, 255, 0.88);
  --glass-border: rgba(255, 255, 255, 0.95);
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  
  --elevation-1: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -1px rgba(0, 0, 0, 0.03);
  --elevation-2: 0 10px 25px -5px rgba(2, 132, 199, 0.12), 0 8px 10px -6px rgba(2, 132, 199, 0.08);
  --elevation-3: 0 20px 30px -10px rgba(2, 132, 199, 0.22);
  
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-full: 9999px;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  background-color: var(--bg-color);
  color: var(--text-main);
  font-family: var(--font-family);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  background-image: linear-gradient(to bottom, #e0f2fe 0%, #f8fafc 100%);
  background-attachment: fixed;
  overflow-x: hidden;
  overflow-wrap: anywhere;
}

body.modal-open {
  overflow: hidden !important;
}

/* 动态下雪背景 */
.snowflakes {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 0;
}

.snowflake {
  position: absolute;
  color: #ffffff;
  font-size: 1.5em;
  font-family: Arial, sans-serif;
  text-shadow: 0 0 5px rgba(0, 0, 0, 0.1);
  animation: fall linear infinite;
  will-change: transform, opacity;
}

@keyframes fall {
  0% { transform: translateY(-10vh) translateX(0) rotate(0deg); opacity: 0.9; }
  100% { transform: translateY(110vh) translateX(20px) rotate(360deg); opacity: 0.2; }
}

.snowflake:nth-child(1) { left: 10%; animation-duration: 10s; animation-delay: -2s; font-size: 1.2em; }
.snowflake:nth-child(2) { left: 20%; animation-duration: 12s; animation-delay: -4s; font-size: 1.8em; }
.snowflake:nth-child(3) { left: 30%; animation-duration: 8s; animation-delay: -1s; font-size: 1.5em; }
.snowflake:nth-child(4) { left: 40%; animation-duration: 14s; animation-delay: -5s; font-size: 1.1em; }
.snowflake:nth-child(5) { left: 50%; animation-duration: 9s; animation-delay: -3s; font-size: 2em; }
.snowflake:nth-child(6) { left: 60%; animation-duration: 11s; animation-delay: 0s; font-size: 1.4em; }
.snowflake:nth-child(7) { left: 70%; animation-duration: 13s; animation-delay: -2.5s; font-size: 1.6em; }
.snowflake:nth-child(8) { left: 80%; animation-duration: 10s; animation-delay: -6s; font-size: 1.3em; }
.snowflake:nth-child(9) { left: 90%; animation-duration: 15s; animation-delay: -1.5s; font-size: 1.7em; }
.snowflake:nth-child(10) { left: 5%; animation-duration: 11s; animation-delay: -7s; font-size: 1.2em; }

a {
  color: var(--accent-color);
  text-decoration: none;
  transition: color 0.25s ease;
}

a:hover {
  color: var(--accent-hover);
}

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

/* Header Navbar */
header, .header-bar {
  padding: 16px 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: rgba(255, 255, 255, 0.75);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-radius: 0 0 var(--radius-md) var(--radius-md);
  margin-bottom: 24px;
  border-bottom: 1px solid var(--glass-border);
  box-shadow: var(--elevation-1);
}

.logo {
  font-size: 24px;
  font-weight: 900;
  color: var(--text-main);
  letter-spacing: 0.5px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.logo span {
  color: var(--accent-color);
}

.header-nav {
  display: flex;
  gap: 24px;
  list-style: none;
}

.header-nav a {
  color: var(--text-main);
  font-weight: 600;
  font-size: 15px;
  transition: color 0.2s ease;
}

.header-nav a:hover {
  color: var(--accent-color);
}

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

/* Mobile Menu Toggle Button */
.mobile-menu-toggle {
  display: none;
  background: transparent;
  border: 1px solid var(--accent-color);
  color: var(--accent-color);
  font-size: 20px;
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  cursor: pointer;
}

/* Buttons System & CVR Hierarchy */
.cta-btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background-color: var(--accent-color);
  color: #ffffff !important;
  font-weight: 700;
  font-size: 17px;
  padding: 14px 32px;
  border-radius: var(--radius-full);
  box-shadow: var(--elevation-2);
  transition: transform 0.28s cubic-bezier(.34, 1.56, .64, 1), background-color 0.2s ease, box-shadow 0.2s ease;
  border: 2px solid transparent;
  text-align: center;
  cursor: pointer;
}

.cta-btn-primary:hover, .cta-btn-primary:focus-visible {
  background-color: var(--accent-hover);
  transform: translateY(-2px);
  box-shadow: var(--elevation-3);
  outline: none;
}

.cta-btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background-color: rgba(2, 132, 199, 0.06);
  color: var(--accent-color) !important;
  font-weight: 700;
  font-size: 17px;
  padding: 14px 32px;
  border-radius: var(--radius-full);
  border: 2px solid var(--accent-color);
  transition: transform 0.28s cubic-bezier(.34, 1.56, .64, 1), background-color 0.2s ease;
  text-align: center;
  cursor: pointer;
}

.cta-btn-secondary:hover, .cta-btn-secondary:focus-visible {
  background-color: rgba(2, 132, 199, 0.12);
  transform: translateY(-2px);
  outline: none;
}

.cta-group {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  align-items: center;
}

/* Microcopy & Trust Elements */
.trust-microcopy {
  margin-top: 14px;
  font-size: 14px;
  color: var(--text-muted);
  font-weight: 500;
}

.trust-pills {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin-bottom: 24px;
}

.trust-pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: rgba(255, 255, 255, 0.9);
  border: 1px solid var(--glass-border);
  box-shadow: 0 2px 8px rgba(2, 132, 199, 0.08);
  padding: 6px 14px;
  border-radius: var(--radius-full);
  font-size: 13px;
  font-weight: 600;
  color: var(--text-main);
}

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

.hero-text {
  flex: 1;
  text-align: left;
}

.hero-text h1 {
  font-size: 46px;
  font-weight: 900;
  line-height: 1.2;
  margin-bottom: 20px;
  color: var(--text-main);
}

.hero-text h1 span {
  color: var(--accent-color);
  background: linear-gradient(135deg, var(--accent-color), var(--accent-light));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-text p {
  font-size: 19px;
  color: var(--text-muted);
  max-width: 92%;
  margin-bottom: 24px;
}

.hero-visual {
  flex: 1;
  display: flex;
  justify-content: center;
  align-items: center;
}

.hero-card {
  background: linear-gradient(135deg, rgba(255,255,255,0.95), rgba(240,248,255,0.95));
  border: 3px solid #ffffff;
  border-radius: var(--radius-lg);
  padding: 40px;
  box-shadow: var(--elevation-2);
  text-align: center;
  width: 100%;
  max-width: 420px;
  transition: transform 0.3s ease;
}

.hero-card:hover {
  transform: translateY(-4px);
}

.hero-card .hero-emoji-icon {
  font-size: 70px;
  display: flex;
  justify-content: center;
  gap: 16px;
  margin-bottom: 16px;
  filter: drop-shadow(0 8px 8px rgba(0,0,0,0.08));
}

.hero-card h3 {
  font-size: 24px;
  color: var(--text-main);
  margin-bottom: 8px;
}

.hero-card p {
  color: var(--accent-color);
  font-weight: 700;
  font-size: 16px;
}

/* Sections Layout */
.section {
  padding: 50px 0;
}

.section-title {
  text-align: center;
  font-size: 34px;
  font-weight: 800;
  margin-bottom: 40px;
  color: var(--text-main);
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.feature-card {
  background: var(--card-bg);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: 32px 24px;
  text-align: center;
  transition: transform 0.28s cubic-bezier(.34, 1.56, .64, 1), box-shadow 0.25s ease;
  box-shadow: var(--elevation-1);
}

.feature-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--elevation-2);
  border-color: var(--accent-light);
}

.feature-icon {
  font-size: 42px;
  margin-bottom: 16px;
}

.feature-card h3 {
  font-size: 20px;
  margin-bottom: 12px;
  color: var(--text-main);
  font-weight: 800;
}

.feature-card p {
  color: var(--text-muted);
  font-size: 15px;
}

/* Promo Banner in Pricing */
.promo-banner {
  background: linear-gradient(135deg, #0284c7, #0369a1);
  color: #ffffff;
  padding: 16px 24px;
  border-radius: var(--radius-md);
  text-align: center;
  margin-bottom: 32px;
  box-shadow: var(--elevation-2);
  font-weight: 700;
  font-size: 16px;
  line-height: 1.5;
}

.promo-banner span.code-tag {
  background: #ffffff;
  color: #0284c7;
  padding: 3px 10px;
  border-radius: var(--radius-sm);
  font-family: monospace;
  font-size: 18px;
  letter-spacing: 1px;
  margin: 0 4px;
}

/* Pricing Grid */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  align-items: stretch;
}

.pricing-card {
  background: var(--card-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: 36px 28px;
  text-align: center;
  position: relative;
  box-shadow: var(--elevation-1);
  transition: transform 0.28s cubic-bezier(.34, 1.56, .64, 1), box-shadow 0.25s ease;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.pricing-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--elevation-2);
}

.pricing-card.featured {
  border: 2px solid var(--accent-color);
  box-shadow: var(--elevation-3);
  background: #ffffff;
}

.pricing-badge {
  position: absolute;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--accent-color);
  color: #ffffff;
  padding: 4px 18px;
  border-radius: var(--radius-full);
  font-weight: 800;
  font-size: 13px;
  box-shadow: 0 4px 10px rgba(2, 132, 199, 0.3);
}

.pricing-card h3 {
  font-size: 22px;
  margin-bottom: 12px;
  color: var(--text-main);
}

.price-tag {
  font-size: 48px;
  font-weight: 900;
  margin-bottom: 24px;
  color: var(--accent-color);
  display: flex;
  align-items: center;
  justify-content: center;
}

.price-tag .currency {
  font-size: 22px;
  margin-right: 4px;
  margin-top: -12px;
}

.price-tag .unit {
  font-size: 15px;
  color: var(--text-muted);
  font-weight: normal;
  margin-left: 4px;
  margin-top: 12px;
}

.pricing-features {
  list-style: none;
  text-align: left;
  margin-bottom: 30px;
  flex-grow: 1;
}

.pricing-features li {
  padding: 10px 0;
  border-bottom: 1px dashed rgba(0,0,0,0.08);
  color: var(--text-muted);
  font-weight: 500;
  font-size: 14px;
}

.pricing-features li::before {
  content: '❄️';
  margin-right: 8px;
  font-size: 12px;
}

.refund-guarantee-pill {
  margin-top: 12px;
  font-size: 12px;
  font-weight: 600;
  color: var(--accent-color);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 4px;
}

/* FAQ Item */
.faq-item {
  background: var(--card-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
  padding: 24px;
  margin-bottom: 16px;
  box-shadow: var(--elevation-1);
}

.faq-item h4 {
  font-size: 17px;
  margin-bottom: 8px;
  color: var(--text-main);
  font-weight: 800;
}

.faq-item p {
  color: var(--text-muted);
  font-size: 15px;
}

/* Reviews */
.review-card {
  text-align: left;
  padding: 28px;
}

.review-stars {
  color: #f59e0b;
  margin-bottom: 12px;
  font-size: 18px;
}

.review-author {
  margin-top: 16px;
  font-weight: 800;
  color: var(--text-main);
  font-size: 14px;
}

/* Article List Grid in Index/SEO */
.article-card {
  text-align: left;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  color: var(--text-main);
  background: var(--card-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: 24px;
  box-shadow: var(--elevation-1);
  transition: transform 0.28s ease, box-shadow 0.25s ease;
}

.article-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--elevation-2);
}

.article-card h3 {
  font-size: 17px;
  margin-bottom: 10px;
  color: var(--text-main);
  font-weight: 800;
}

.article-card p {
  font-size: 14px;
  color: var(--text-muted);
}

/* Footer Section */
footer, .footer-bar {
  border-top: 1px solid rgba(2, 132, 199, 0.15);
  padding: 48px 0 24px;
  margin-top: 40px;
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  margin-bottom: 32px;
}

.footer-links {
  display: flex;
  gap: 24px;
}

.footer-links a {
  color: var(--text-muted);
  font-weight: 600;
  font-size: 14px;
}

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

.copyright {
  text-align: center;
  color: var(--text-muted);
  font-size: 13px;
}

.friendly-links {
  margin-top: 16px;
  font-size: 13px;
  padding: 10px 16px;
  background: rgba(2, 132, 199, 0.05);
  border-radius: var(--radius-sm);
  display: inline-block;
}

/* Mandatory Component C4: Sticky Mobile CTA Bar */
.sticky-mobile-cta {
  display: none;
}

@media (max-width: 768px) {
  body {
    padding-bottom: 76px; /* Reserve space for sticky bar to prevent footer overlap */
  }

  .sticky-mobile-cta {
    display: flex;
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.88);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-top: 1px solid var(--glass-border);
    padding: 10px 16px;
    padding-bottom: calc(10px + env(safe-area-inset-bottom));
    gap: 12px;
    box-shadow: 0 -4px 20px rgba(0, 0, 0, 0.08);
  }

  .sticky-mobile-cta a {
    flex: 1;
    padding: 12px 16px;
    font-size: 15px;
    border-radius: var(--radius-full);
  }

  .mobile-menu-toggle {
    display: block;
  }

  .header-nav {
    display: none;
    width: 100%;
    flex-direction: column;
    gap: 12px;
    padding-top: 12px;
  }

  .header-nav.nav-open {
    display: flex;
  }

  header, .header-bar {
    flex-wrap: wrap;
  }

  .hero {
    flex-direction: column;
    text-align: center;
    padding: 20px 0 40px;
  }

  .hero-text {
    text-align: center;
  }

  .hero-text h1 {
    font-size: 34px;
  }

  .hero-text p {
    font-size: 16px;
    margin: 0 auto 20px;
  }

  .hero-text .cta-group {
    justify-content: center;
  }

  .hero-visual {
    width: 100%;
  }

  .grid-3, .grid-2, .pricing-grid {
    grid-template-columns: 1fr;
  }

  .pricing-card.featured {
    transform: none;
  }

  .footer-content {
    flex-direction: column;
    gap: 20px;
    text-align: center;
  }

  .footer-links {
    flex-wrap: wrap;
    justify-content: center;
    gap: 16px;
  }
}

/* Mandatory Component C5: Exit-Intent Popup */
.exit-popup-backdrop {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(15, 23, 42, 0.6);
  backdrop-filter: blur(6px);
  -webkit-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;
  padding: 20px;
}

.exit-popup-backdrop.popup-active {
  opacity: 1;
  visibility: visible;
}

.exit-popup-card {
  background: #ffffff;
  border-radius: var(--radius-lg);
  padding: 36px 32px;
  max-width: 440px;
  width: 100%;
  text-align: center;
  position: relative;
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
  transform: scale(0.92);
  transition: transform 0.25s cubic-bezier(.34, 1.56, .64, 1);
}

.exit-popup-backdrop.popup-active .exit-popup-card {
  transform: scale(1);
}

.exit-popup-close {
  position: absolute;
  top: 14px;
  right: 16px;
  background: transparent;
  border: none;
  font-size: 24px;
  color: var(--text-muted);
  cursor: pointer;
  line-height: 1;
  padding: 4px 8px;
  border-radius: var(--radius-sm);
}

.exit-popup-close:hover {
  color: var(--text-main);
  background: rgba(0,0,0,0.05);
}

.exit-popup-card h3 {
  font-size: 24px;
  color: var(--text-main);
  margin-bottom: 10px;
  font-weight: 900;
}

.exit-popup-card p {
  font-size: 15px;
  color: var(--text-muted);
  margin-bottom: 20px;
}

.coupon-box {
  background: rgba(2, 132, 199, 0.06);
  border: 2px dashed var(--accent-color);
  border-radius: var(--radius-md);
  padding: 16px;
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.coupon-code-text {
  font-family: monospace;
  font-size: 22px;
  font-weight: 800;
  color: var(--accent-color);
  letter-spacing: 2px;
}

.copy-btn {
  background: var(--accent-color);
  color: #ffffff;
  border: none;
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  font-weight: 700;
  font-size: 14px;
  cursor: pointer;
  transition: background-color 0.2s ease;
}

.copy-btn:hover {
  background: var(--accent-hover);
}

.copy-btn.copied {
  background: var(--success-color);
}

/* Accessibility: Reduced Motion */
@media (prefers-reduced-motion: reduce) {
  .snowflake, .hero-card, .cta-btn-primary, .cta-btn-secondary, .feature-card, .pricing-card, .exit-popup-card {
    animation: none !important;
    transition: none !important;
  }
}