@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+SC:wght@300;400;500;600;700&family=Noto+Serif+SC:wght@400;600;700&display=swap');
@import url('variables.css');

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

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

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

body::before {
  content: '';
  position: fixed;
  inset: 0;
  background-image: radial-gradient(circle at 20% 20%, rgba(26, 92, 69, 0.03) 0%, transparent 50%),
    radial-gradient(circle at 80% 80%, rgba(200, 149, 108, 0.04) 0%, transparent 50%);
  pointer-events: none;
  z-index: -1;
}

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

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

ul { list-style: none; }

.container {
  width: min(1180px, 90vw);
  margin: 0 auto;
}

/* Header */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: rgba(247, 244, 239, 0.88);
  backdrop-filter: blur(16px) saturate(1.2);
  border-bottom: 1px solid rgba(221, 213, 200, 0.6);
  z-index: 1000;
  transition: var(--transition);
}

.site-header.scrolled {
  background: rgba(255, 255, 255, 0.95);
  box-shadow: var(--shadow-sm);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--color-primary-dark);
  letter-spacing: 0.02em;
}

.logo-icon {
  width: 42px;
  height: 42px;
  background: linear-gradient(145deg, var(--color-primary), var(--color-primary-light));
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 12px rgba(26, 92, 69, 0.25);
}

.logo-icon svg {
  width: 22px;
  height: 22px;
  fill: white;
}

.nav-links {
  display: flex;
  gap: 4px;
}

.nav-links a {
  position: relative;
  padding: 10px 18px;
  border-radius: var(--radius-sm);
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--color-text-muted);
  transition: var(--transition);
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: 6px;
  left: 50%;
  width: 0;
  height: 2px;
  background: var(--color-accent);
  transition: var(--transition);
  transform: translateX(-50%);
  border-radius: 1px;
}

.nav-links a:hover {
  color: var(--color-primary);
}

.nav-links a:hover::after,
.nav-links a.active::after {
  width: 24px;
}

.nav-links a.active {
  color: var(--color-primary-dark);
  font-weight: 600;
}

.menu-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.menu-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-primary);
  margin: 5px 0;
  border-radius: 1px;
  transition: var(--transition);
}

/* Hero */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: var(--header-height);
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(105deg, rgba(15, 61, 46, 0.88) 0%, rgba(26, 92, 69, 0.55) 45%, rgba(15, 61, 46, 0.35) 100%),
    url('../image/hero.jpg') center/cover no-repeat;
  z-index: -2;
  transform: scale(1.02);
  animation: heroZoom 20s ease-in-out infinite alternate;
}

@keyframes heroZoom {
  from { transform: scale(1.02); }
  to { transform: scale(1.08); }
}

.hero::after {
  content: '';
  position: absolute;
  inset: 0;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.03'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
  z-index: -1;
  opacity: 0.5;
}

.hero-content {
  color: white;
  max-width: 680px;
  padding: 80px 0 100px;
}

.hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 18px;
  background: rgba(255, 255, 255, 0.12);
  border: 1px solid rgba(255, 255, 255, 0.22);
  border-radius: 30px;
  font-size: 0.82rem;
  font-weight: 500;
  margin-bottom: 28px;
  backdrop-filter: blur(8px);
  letter-spacing: 0.05em;
}

.hero-tag::before {
  content: '';
  width: 6px;
  height: 6px;
  background: var(--color-accent-light);
  border-radius: 50%;
  box-shadow: 0 0 8px var(--color-accent-light);
}

.hero h1 {
  font-family: var(--font-serif);
  font-size: clamp(2.4rem, 5.5vw, 3.8rem);
  line-height: 1.25;
  margin-bottom: 24px;
  font-weight: 700;
  text-shadow: 0 2px 24px rgba(0, 0, 0, 0.2);
}

.hero p {
  font-size: 1.05rem;
  opacity: 0.92;
  margin-bottom: 36px;
  line-height: 1.9;
  max-width: 560px;
}

.hero-actions {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}

.hero-scroll {
  position: absolute;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%);
  color: rgba(255, 255, 255, 0.6);
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

.hero-scroll::after {
  content: '';
  width: 1px;
  height: 40px;
  background: linear-gradient(to bottom, rgba(255,255,255,0.5), transparent);
  animation: scrollLine 2s ease infinite;
}

@keyframes scrollLine {
  0%, 100% { opacity: 0.3; transform: scaleY(0.6); }
  50% { opacity: 1; transform: scaleY(1); }
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 30px;
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: var(--transition);
  font-family: inherit;
  letter-spacing: 0.02em;
}

.btn-primary {
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-light));
  color: var(--color-primary-dark);
  box-shadow: 0 4px 16px rgba(200, 149, 108, 0.35);
}

.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 28px rgba(200, 149, 108, 0.45);
}

.btn-outline {
  background: rgba(255, 255, 255, 0.08);
  color: white;
  border: 1.5px solid rgba(255, 255, 255, 0.45);
  backdrop-filter: blur(4px);
}

.btn-outline:hover {
  background: rgba(255, 255, 255, 0.18);
  border-color: white;
}

.btn-secondary {
  background: var(--color-primary);
  color: white;
  box-shadow: 0 4px 16px rgba(26, 92, 69, 0.25);
}

.btn-secondary:hover {
  background: var(--color-primary-dark);
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

/* Sections */
.section {
  padding: 96px 0;
  position: relative;
}

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

.section-label {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 12px;
}

.section-header h2 {
  font-family: var(--font-serif);
  font-size: clamp(1.9rem, 3.5vw, 2.6rem);
  color: var(--color-primary-dark);
  margin-bottom: 14px;
  font-weight: 700;
}

.section-header p {
  color: var(--color-text-muted);
  max-width: 560px;
  margin: 0 auto;
  font-size: 1rem;
}

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

.section-alt::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--color-border), transparent);
}

/* Cards */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 28px;
}

.card {
  background: var(--color-surface);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  border: 1px solid var(--color-border);
}

.card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
  border-color: rgba(26, 92, 69, 0.15);
}

.card-image {
  height: 220px;
  overflow: hidden;
  position: relative;
}

.card-image::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(to top, rgba(15, 61, 46, 0.35) 0%, transparent 50%);
  opacity: 0;
  transition: var(--transition);
}

.card:hover .card-image::after {
  opacity: 1;
}

.card-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.card:hover .card-image img {
  transform: scale(1.06);
}

.card-badge {
  position: absolute;
  top: 14px;
  left: 14px;
  padding: 5px 14px;
  background: rgba(15, 61, 46, 0.85);
  color: white;
  font-size: 0.72rem;
  font-weight: 600;
  border-radius: 20px;
  backdrop-filter: blur(4px);
  letter-spacing: 0.03em;
  z-index: 1;
}

.card-body {
  padding: 22px 24px 26px;
}

.card-body h3 {
  font-family: var(--font-serif);
  font-size: 1.2rem;
  margin-bottom: 10px;
  color: var(--color-primary-dark);
  font-weight: 600;
}

.card-body p {
  font-size: 0.88rem;
  color: var(--color-text-muted);
  margin-bottom: 16px;
  line-height: 1.75;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.card-link {
  color: var(--color-primary);
  font-weight: 600;
  font-size: 0.85rem;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: var(--transition);
}

.card-link:hover {
  color: var(--color-primary-light);
  gap: 10px;
}

/* Feature blocks */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.feature-item {
  position: relative;
  padding: 0;
  background: var(--color-surface);
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  transition: var(--transition);
  overflow: hidden;
  display: block;
}

.feature-item:hover {
  border-color: rgba(26, 92, 69, 0.2);
  box-shadow: var(--shadow-md);
  transform: translateY(-4px);
}

.feature-thumb {
  height: 140px;
  overflow: hidden;
}

.feature-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}

.feature-item:hover .feature-thumb img {
  transform: scale(1.08);
}

.feature-body {
  padding: 22px 20px 26px;
}

.feature-num {
  font-family: var(--font-serif);
  font-size: 2rem;
  font-weight: 700;
  color: rgba(26, 92, 69, 0.12);
  line-height: 1;
  margin-bottom: 8px;
}

.feature-item h3 {
  font-family: var(--font-serif);
  margin-bottom: 8px;
  color: var(--color-primary-dark);
  font-size: 1.05rem;
  font-weight: 600;
}

.feature-item p {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  line-height: 1.65;
}

.feature-arrow {
  position: absolute;
  bottom: 20px;
  right: 20px;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--color-bg-alt);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.9rem;
  color: var(--color-primary);
  transition: var(--transition);
}

.feature-item:hover .feature-arrow {
  background: var(--color-primary);
  color: white;
}

/* Stats */
.stats-bar {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0;
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border);
  overflow: hidden;
  box-shadow: var(--shadow-md);
}

.stat-item {
  text-align: center;
  padding: 40px 24px;
  position: relative;
  color: var(--color-primary-dark);
}

.stat-item:not(:last-child)::after {
  content: '';
  position: absolute;
  right: 0;
  top: 25%;
  height: 50%;
  width: 1px;
  background: var(--color-border);
}

.stat-number {
  font-family: var(--font-serif);
  font-size: 2.8rem;
  font-weight: 700;
  line-height: 1;
  margin-bottom: 10px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-light));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.stat-label {
  font-size: 0.88rem;
  color: var(--color-text-muted);
  font-weight: 500;
}

/* AI steps section */
.ai-steps-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: center;
}

.ai-steps-content h3 {
  font-family: var(--font-serif);
  font-size: 1.6rem;
  margin-bottom: 28px;
  color: var(--color-primary-dark);
}

.step-list {
  display: flex;
  flex-direction: column;
  gap: 20px;
  margin-bottom: 32px;
}

.step-item {
  display: flex;
  gap: 18px;
  align-items: flex-start;
}

.step-num {
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-light));
  color: white;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1rem;
  flex-shrink: 0;
  box-shadow: 0 4px 12px rgba(26, 92, 69, 0.2);
}

.step-text {
  padding-top: 8px;
  font-size: 0.95rem;
  color: var(--color-text);
  line-height: 1.6;
}

.ai-preview {
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
  position: relative;
}

.ai-preview img {
  width: 100%;
  height: 380px;
  object-fit: cover;
}

.ai-preview-badge {
  position: absolute;
  bottom: 20px;
  left: 20px;
  padding: 10px 18px;
  background: rgba(255, 255, 255, 0.92);
  border-radius: var(--radius-sm);
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--color-primary-dark);
  backdrop-filter: blur(8px);
}

/* Page header */
.page-hero {
  position: relative;
  padding: calc(var(--header-height) + 72px) 0 72px;
  color: white;
  text-align: center;
  overflow: hidden;
}

.page-hero-bg {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center;
  z-index: -2;
}

.page-hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(15, 61, 46, 0.82), rgba(26, 92, 69, 0.65));
  z-index: -1;
}

.page-hero h1 {
  font-family: var(--font-serif);
  font-size: clamp(2.2rem, 4.5vw, 3rem);
  margin-bottom: 14px;
  font-weight: 700;
}

.page-hero p {
  opacity: 0.9;
  max-width: 560px;
  margin: 0 auto;
  font-size: 1.05rem;
}

.page-hero-guide .page-hero-bg { background-image: url('../image/mutianyu2.jpg'); }
.page-hero-geo .page-hero-bg { background-image: url('../image/geology.jpg'); }
.page-hero-learn .page-hero-bg { background-image: url('../image/forest.jpg'); }
.page-hero-studio .page-hero-bg { background-image: url('../image/studio-preview.jpg'); }

/* Footer */
.site-footer {
  background: var(--color-primary-dark);
  color: rgba(255, 255, 255, 0.75);
  padding: 56px 0 28px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 48px;
}

.footer-brand h3 {
  font-family: var(--font-serif);
  color: white;
  margin-bottom: 14px;
  font-size: 1.2rem;
}

.footer-brand p {
  font-size: 0.88rem;
  line-height: 1.85;
}

.footer-col h4 {
  color: white;
  margin-bottom: 18px;
  font-size: 0.92rem;
  font-weight: 600;
  letter-spacing: 0.05em;
}

.footer-col a {
  display: block;
  font-size: 0.88rem;
  padding: 5px 0;
  transition: var(--transition);
  opacity: 0.8;
}

.footer-col a:hover {
  color: var(--color-accent-light);
  opacity: 1;
  padding-left: 4px;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding-top: 28px;
  text-align: center;
  font-size: 0.82rem;
  opacity: 0.55;
}

.text-center { text-align: center; }
.mt-40 { margin-top: 40px; }

/* Animations */
.fade-in {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

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

/* Responsive */
@media (max-width: 1024px) {
  .feature-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    background: white;
    flex-direction: column;
    padding: 16px;
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-md);
  }

  .nav-links.open { display: flex; }
  .menu-toggle { display: block; }

  .stats-bar { grid-template-columns: repeat(2, 1fr); }
  .stat-item:nth-child(2)::after { display: none; }

  .footer-grid { grid-template-columns: 1fr; gap: 28px; }
  .hero-actions { flex-direction: column; }
  .btn { justify-content: center; }
  .feature-grid { grid-template-columns: 1fr; }
  .ai-steps-grid { grid-template-columns: 1fr; }
  .hero-scroll { display: none; }
}