/* ==========================================================================
   VSPA Official Website – style.20260712.css
   Self-contained, mobile-first, WeChat-compatible
   ========================================================================== */

/* --------------------------------------------------------------------------
   0. Local @font-face – Noto Sans SC + Inter
   -------------------------------------------------------------------------- */
@font-face {
  font-family: 'Noto Sans SC';
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: local('Noto Sans SC'), local('NotoSansSC-Regular'),
       url('../fonts/NotoSansSC-Regular.woff2') format('woff2'),
       url('../fonts/NotoSansSC-Regular.woff')  format('woff');
}

@font-face {
  font-family: 'Noto Sans SC';
  font-style: normal;
  font-weight: 700;
  font-display: swap;
  src: local('Noto Sans SC Bold'), local('NotoSansSC-Bold'),
       url('../fonts/NotoSansSC-Bold.woff2') format('woff2'),
       url('../fonts/NotoSansSC-Bold.woff')  format('woff');
}

@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: local('Inter'), local('Inter-Regular'),
       url('../fonts/Inter-Regular.woff2') format('woff2'),
       url('../fonts/Inter-Regular.woff')  format('woff');
}

@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 600;
  font-display: swap;
  src: local('Inter SemiBold'), local('Inter-SemiBold'),
       url('../fonts/Inter-SemiBold.woff2') format('woff2'),
       url('../fonts/Inter-SemiBold.woff')  format('woff');
}

@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 700;
  font-display: swap;
  src: local('Inter Bold'), local('Inter-Bold'),
       url('../fonts/Inter-Bold.woff2') format('woff2'),
       url('../fonts/Inter-Bold.woff')  format('woff');
}

/* --------------------------------------------------------------------------
   1. CSS Custom Properties
   -------------------------------------------------------------------------- */
:root {
  /* Palette */
  --color-primary:    #0F2B4C;
  --color-primary-90: rgba(15, 43, 76, 0.9);
  --color-accent:     #c9a84c;
  --color-accent-dark:#b09030;
  --color-alt-bg:     #F0F4F8;
  --color-white:      #FFFFFF;
  --color-text:       #333333;
  --color-muted:      #666666;

  /* Typography */
  --font-body:   'Noto Sans SC', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-heading:'Noto Sans SC', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

  /* Spacing & layout */
  --max-width:     1200px;
  --section-pad:   60px 20px;
  --card-radius:   8px;
  --card-shadow:   0 2px 12px rgba(0, 0, 0, 0.07);
  --card-shadow-hv:0 4px 20px rgba(0, 0, 0, 0.12);
  --btn-radius:    6px;

  /* Transitions */
  --transition-speed: 0.25s;
  --transition-ease:  ease;
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  -ms-text-size-adjust: 100%;
}

body {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text);
  background: var(--color-white);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

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

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

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

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  line-height: 1.3;
  color: var(--color-primary);
}

/* --------------------------------------------------------------------------
   3. Utilities
   -------------------------------------------------------------------------- */

/* Container */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 20px;
  padding-right: 20px;
}

/* Sections */
.section {
  padding: var(--section-pad);
  background: var(--color-white);
}

.section-alt {
  padding: var(--section-pad);
  background: var(--color-alt-bg);
}

/* Section Title */
.section-title {
  font-size: 28px;
  font-weight: 700;
  text-align: center;
  margin-bottom: 40px;
  position: relative;
  padding-bottom: 16px;
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 50px;
  height: 3px;
  background: var(--color-accent);
  border-radius: 2px;
}

/* --------------------------------------------------------------------------
   4. Buttons
   -------------------------------------------------------------------------- */
.btn {
  display: inline-block;
  font-family: var(--font-body);
  font-size: 16px;
  font-weight: 600;
  line-height: 1;
  text-align: center;
  padding: 12px 28px;
  border-radius: var(--btn-radius);
  border: 2px solid transparent;
  cursor: pointer;
  transition:
    background-color var(--transition-speed) var(--transition-ease),
    color            var(--transition-speed) var(--transition-ease),
    border-color     var(--transition-speed) var(--transition-ease),
    transform        var(--transition-speed) var(--transition-ease),
    opacity          var(--transition-speed) var(--transition-ease);
  text-decoration: none;
  -webkit-tap-highlight-color: transparent;
  user-select: none;
  will-change: transform, opacity;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn:active {
  transform: translateY(0);
}

/* Primary gold CTA */
.btn-primary,
.btn-gold {
  background: var(--color-accent);
  color: var(--color-white);
  border-color: var(--color-accent);
}

.btn-primary:hover,
.btn-primary:focus,
.btn-gold:hover,
.btn-gold:focus {
  background: var(--color-accent-dark);
  border-color: var(--color-accent-dark);
  color: var(--color-white);
}

/* Outline / secondary */
.btn-outline {
  background: transparent;
  color: var(--color-accent);
  border-color: var(--color-accent);
}

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

/* --------------------------------------------------------------------------
   5. Navigation
   -------------------------------------------------------------------------- */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--color-primary);
  padding: 0;
  box-shadow: 0 1px 8px rgba(0, 0, 0, 0.15);
}

.nav > .container,
.nav .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 56px;
  padding-top: 0;
  padding-bottom: 0;
}

.nav-logo {
  font-size: 22px;
  font-weight: 700;
  color: var(--color-white);
  text-decoration: none;
  white-space: nowrap;
}

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

.nav-links {
  display: flex;
  list-style: none;
  gap: 24px;
  align-items: center;
  margin: 0;
  padding: 0;
}

.nav-links a {
  font-size: 15px;
  font-weight: 500;
  color: rgba(255, 255, 255, 0.85);
  text-decoration: none;
  padding: 8px 0;
  position: relative;
  transition: color var(--transition-speed) var(--transition-ease);
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: 2px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-accent);
  transition: width var(--transition-speed) var(--transition-ease);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--color-white);
}

.nav-links a:hover::after,
.nav-links a.active::after {
  width: 100%;
}

/* Mobile nav — simple stacked approach */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
  color: var(--color-white);
  font-size: 24px;
  line-height: 1;
}

/* --------------------------------------------------------------------------
   6. Hero
   -------------------------------------------------------------------------- */
.hero {
  background: linear-gradient(135deg, #0F2B4C 0%, #1a3d5c 50%, #0F2B4C 100%);
  color: var(--color-white);
  text-align: center;
  padding: 80px 20px 80px;
  position: relative;
  overflow: hidden;
}

.hero-title {
  font-size: 32px;
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: 16px;
  line-height: 1.2;
}

.hero-subtitle {
  font-size: 17px;
  color: rgba(255, 255, 255, 0.85);
  margin-bottom: 32px;
  line-height: 1.6;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  justify-content: center;
}

/* --------------------------------------------------------------------------
   7. Cards
   -------------------------------------------------------------------------- */
.card {
  background: var(--color-white);
  border-radius: var(--card-radius);
  box-shadow: var(--card-shadow);
  padding: 24px;
  transition:
    box-shadow var(--transition-speed) var(--transition-ease),
    transform  var(--transition-speed) var(--transition-ease);
  will-change: transform;
}

.card:hover {
  box-shadow: var(--card-shadow-hv);
  transform: translateY(-3px);
}

/* 3-col grid */
.card-3col {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
}

/* 4-col grid */
.card-4col {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
}

/* --------------------------------------------------------------------------
   8. Pricing Cards
   -------------------------------------------------------------------------- */
.pricing-card {
  background: var(--color-white);
  border-radius: var(--card-radius);
  box-shadow: var(--card-shadow);
  padding: 28px 24px;
  text-align: center;
  transition:
    box-shadow var(--transition-speed) var(--transition-ease),
    transform  var(--transition-speed) var(--transition-ease);
  position: relative;
  overflow: hidden;
  will-change: transform;
}

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

.pricing-featured {
  border: 2px solid var(--color-accent);
  transform: scale(1.02);
  box-shadow: 0 4px 24px rgba(201, 168, 76, 0.15);
}

.pricing-featured:hover {
  transform: scale(1.02) translateY(-4px);
}

.pricing-featured::before {
  content: '推荐';
  position: absolute;
  top: 12px;
  right: -32px;
  background: var(--color-accent);
  color: var(--color-white);
  font-size: 12px;
  font-weight: 600;
  padding: 4px 36px;
  transform: rotate(45deg);
}

/* --------------------------------------------------------------------------
   9. Stats
   -------------------------------------------------------------------------- */
.stats-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  text-align: center;
}

.stat-item {
  padding: 20px;
}

.stat-number {
  font-size: 36px;
  font-weight: 700;
  color: var(--color-primary);
  display: block;
  margin-bottom: 6px;
  line-height: 1.1;
}

.stat-item p {
  font-size: 14px;
  color: var(--color-muted);
  margin: 0;
}

/* --------------------------------------------------------------------------
   10. FAQ – Native <details>/<summary>
   -------------------------------------------------------------------------- */
.faq {
  max-width: 800px;
  margin: 0 auto;
}

.faq details {
  background: var(--color-white);
  border: 1px solid #e0e6ed;
  border-radius: var(--card-radius);
  margin-bottom: 12px;
  overflow: hidden;
  transition: box-shadow var(--transition-speed) var(--transition-ease);
}

.faq details:hover {
  box-shadow: 0 1px 6px rgba(0, 0, 0, 0.06);
}

.faq details[open] {
  box-shadow: 0 1px 8px rgba(0, 0, 0, 0.08);
}

.faq summary {
  padding: 16px 20px;
  font-weight: 600;
  font-size: 16px;
  color: var(--color-primary);
  cursor: pointer;
  list-style: none;            /* hide default triangle */
  display: flex;
  align-items: center;
  justify-content: space-between;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
  outline: none;
}

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

.faq summary::after {
  content: '+';
  font-size: 20px;
  font-weight: 400;
  color: var(--color-accent);
  transition: transform var(--transition-speed) var(--transition-ease);
  flex-shrink: 0;
  margin-left: 12px;
}

.faq details[open] > summary::after {
  transform: rotate(45deg);
}

.faq details .faq-body {
  padding: 0 20px 18px;
  color: var(--color-muted);
  font-size: 15px;
  line-height: 1.7;
}

/* --------------------------------------------------------------------------
   11. Footer
   -------------------------------------------------------------------------- */
.footer {
  background: var(--color-primary);
  color: rgba(255, 255, 255, 0.75);
  padding: 48px 20px 32px;
  font-size: 14px;
}

.footer .container {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
}

.footer-col h4 {
  color: var(--color-white);
  font-size: 16px;
  margin-bottom: 14px;
}

.footer-col p,
.footer-col li {
  color: rgba(255, 255, 255, 0.65);
  line-height: 1.7;
  margin-bottom: 6px;
}

.footer-col ul {
  list-style: none;
  padding: 0;
}

.footer-col a {
  color: rgba(255, 255, 255, 0.65);
  text-decoration: none;
  transition: color var(--transition-speed) var(--transition-ease);
}

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

.footer-bottom {
  text-align: center;
  padding-top: 24px;
  margin-top: 24px;
  border-top: 1px solid rgba(255, 255, 255, 0.12);
  color: rgba(255, 255, 255, 0.45);
  font-size: 13px;
}

/* --------------------------------------------------------------------------
   12. CTA Floating Button
   -------------------------------------------------------------------------- */
.cta-float {
  position: fixed;
  bottom: 24px;
  right: 24px;
  z-index: 200;
  background: var(--color-accent);
  color: var(--color-white);
  font-weight: 700;
  font-size: 15px;
  padding: 14px 24px;
  border-radius: 28px;
  box-shadow: 0 4px 18px rgba(201, 168, 76, 0.45);
  text-decoration: none;
  transition:
    background var(--transition-speed) var(--transition-ease),
    transform  var(--transition-speed) var(--transition-ease),
    opacity    var(--transition-speed) var(--transition-ease);
  will-change: transform, opacity;
  -webkit-tap-highlight-color: transparent;
}

.cta-float:hover {
  background: var(--color-accent-dark);
  transform: translateY(-2px);
}

.cta-float:active {
  transform: scale(0.97);
}

/* --------------------------------------------------------------------------
   13. WeChat Badge
   -------------------------------------------------------------------------- */
.wechat-badge {
  position: fixed;
  top: 80px;
  right: 20px;
  z-index: 150;
  background: var(--color-white);
  color: var(--color-primary);
  border: 2px solid var(--color-accent);
  border-radius: 8px;
  padding: 10px 14px;
  font-size: 13px;
  font-weight: 600;
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.1);
  display: flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
  transition:
    box-shadow var(--transition-speed) var(--transition-ease),
    transform  var(--transition-speed) var(--transition-ease);
  will-change: transform;
}

.wechat-badge:hover {
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.15);
  transform: translateY(-1px);
}

/* --------------------------------------------------------------------------
   14. Scroll Animations – fadeInUp (GPU-friendly)
   -------------------------------------------------------------------------- */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition:
    opacity 0.6s ease-out,
    transform 0.6s ease-out;
  will-change: transform, opacity;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Staggered delays (optional, assign via class) */
.fade-in-delay-1 { transition-delay: 0.1s; }
.fade-in-delay-2 { transition-delay: 0.2s; }
.fade-in-delay-3 { transition-delay: 0.3s; }
.fade-in-delay-4 { transition-delay: 0.4s; }

/* --------------------------------------------------------------------------
   15. Misc Components
   -------------------------------------------------------------------------- */

/* Divider */
.divider-gold {
  width: 60px;
  height: 3px;
  background: var(--color-accent);
  margin: 16px auto;
  border-radius: 2px;
}

/* Badge / Tag */
.tag {
  display: inline-block;
  padding: 4px 12px;
  border-radius: 14px;
  font-size: 12px;
  font-weight: 600;
  background: rgba(201, 168, 76, 0.12);
  color: var(--color-accent);
}

/* --------------------------------------------------------------------------
   16. Responsive – Tablet (≥ 768px)
   -------------------------------------------------------------------------- */
@media (min-width: 768px) {
  .container {
    padding-left: 32px;
    padding-right: 32px;
  }

  .section,
  .section-alt {
    padding: 80px 32px;
  }

  .section-title {
    font-size: 32px;
  }

  .hero {
    padding: 100px 32px 100px;
  }

  .hero-title {
    font-size: 42px;
  }

  .hero-subtitle {
    font-size: 18px;
  }

  .btn {
    padding: 14px 34px;
    font-size: 17px;
  }

  .card-3col {
    grid-template-columns: repeat(2, 1fr);
  }

  .card-4col {
    grid-template-columns: repeat(2, 1fr);
  }

  .pricing-card {
    padding: 32px 28px;
  }

  .stats-grid {
    grid-template-columns: repeat(4, 1fr);
  }

  .stat-number {
    font-size: 44px;
  }

  .footer .container {
    grid-template-columns: repeat(2, 1fr);
  }

  .nav > .container,
  .nav .container {
    min-height: 64px;
  }

  .nav-logo {
    font-size: 24px;
  }

  .faq summary {
    font-size: 17px;
    padding: 18px 24px;
  }

  .faq details .faq-body {
    padding: 0 24px 20px;
  }
}

/* --------------------------------------------------------------------------
   17. Responsive – Desktop (≥ 1024px)
   -------------------------------------------------------------------------- */
@media (min-width: 1024px) {
  .container {
    padding-left: 40px;
    padding-right: 40px;
  }

  .section,
  .section-alt {
    padding: 100px 40px;
  }

  .hero {
    padding: 130px 40px 130px;
  }

  .hero-title {
    font-size: 52px;
  }

  .hero-subtitle {
    font-size: 20px;
  }

  .card-3col {
    grid-template-columns: repeat(3, 1fr);
  }

  .card-4col {
    grid-template-columns: repeat(4, 1fr);
  }

  .footer .container {
    grid-template-columns: repeat(3, 1fr);
  }

  .nav > .container,
  .nav .container {
    min-height: 72px;
  }

  .nav-links {
    gap: 32px;
  }

  .nav-links a {
    font-size: 16px;
  }

  .stat-number {
    font-size: 52px;
  }
}

/* --------------------------------------------------------------------------
   18. Large Desktop (> 1400px)
   -------------------------------------------------------------------------- */
@media (min-width: 1400px) {
  .hero-title {
    font-size: 60px;
  }
}

/* --------------------------------------------------------------------------
   19. Print Styles
   -------------------------------------------------------------------------- */
@media print {
  *,
  *::before,
  *::after {
    background: transparent !important;
    color: #000 !important;
    box-shadow: none !important;
    text-shadow: none !important;
  }

  body {
    font-size: 12pt;
    line-height: 1.5;
  }

  .nav,
  .footer,
  .cta-float,
  .wechat-badge,
  .hero-cta .btn {
    display: none !important;
  }

  .hero {
    padding: 20px 0;
    text-align: left;
  }

  .hero-title {
    font-size: 22pt;
  }

  .hero-subtitle {
    font-size: 12pt;
  }

  .section,
  .section-alt {
    padding: 16px 0;
    page-break-inside: avoid;
  }

  .container {
    max-width: 100%;
    padding: 0;
  }

  a[href]::after {
    content: ' (' attr(href) ')';
    font-size: 10pt;
    color: #555;
  }

  .card-3col,
  .card-4col,
  .stats-grid,
  .footer .container {
    grid-template-columns: 1fr 1fr;
  }
}