/* ===== CSS Variables ===== */
:root {
  --color-primary: #E5A414;
  --color-primary-dark: #c8900f;
  --color-text: #111827;
  --color-text-muted: #6B7280;
  --color-bg: #F8FAFC;
  --color-border: #E5E7EB;
  --font-base: 'Inter', -apple-system, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --radius: 8px;
  --shadow: 0 4px 16px rgba(0, 0, 0, 0.08);
  --max-width: 1200px;
}

/* ===== Reset ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: smooth; }
body { font-family: var(--font-base); color: var(--color-text); line-height: 1.7; background: #fff; }
a { text-decoration: none; color: inherit; }
img { max-width: 100%; display: block; }
ul, ol { list-style: none; }

/* ===== Container ===== */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 30px;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 28px;
  border-radius: var(--radius);
  font-size: 16px;
  font-weight: 500;
  font-family: var(--font-base);
  cursor: pointer;
  transition: all 0.2s ease;
  min-height: 44px;
  border: 2px solid transparent;
  white-space: nowrap;
}
.btn-primary { background: var(--color-primary); color: #fff; }
.btn-primary:hover { background: var(--color-primary-dark); transform: translateY(-1px); box-shadow: 0 6px 20px rgba(229, 164, 20, 0.4); }
.btn-outline { background: transparent; border-color: var(--color-primary); color: var(--color-primary); }
.btn-outline:hover { background: var(--color-primary); color: #fff; }
.btn-ghost { background: rgba(255,255,255,0.12); border-color: rgba(255,255,255,0.5); color: #fff; }
.btn-ghost:hover { background: rgba(255,255,255,0.22); }

/* ===== Section Base ===== */
.section { padding: 80px 0; }
.section-alt { background: var(--color-bg); }
.section-dark { background: #1F2937; }
.section-header { text-align: center; margin-bottom: 56px; }
.section-header .en-sub { font-size: 13px; color: var(--color-primary); font-weight: 600; letter-spacing: 2px; text-transform: uppercase; display: block; margin-bottom: 10px; }
.section-header h2 { font-size: 36px; font-weight: 600; line-height: 1.3; color: var(--color-text); }
.section-header p { font-size: 16px; color: var(--color-text-muted); margin-top: 14px; max-width: 680px; margin-left: auto; margin-right: auto; }
.text-accent { color: var(--color-primary); }

/* ===== Header ===== */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  background: #fff;
  border-bottom: 1px solid var(--color-border);
  height: 64px;
  display: flex;
  align-items: center;
}
.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
}
.header-logo img { height: 48px; width: auto; }
.header-nav { display: flex; align-items: center; gap: 36px; }
.header-nav a { font-size: 15px; color: #374151; font-weight: 500; transition: color 0.2s; }
.header-nav a:hover, .header-nav a.active { color: var(--color-primary); }
.header-cta { display: flex; align-items: center; gap: 12px; }
.header-cta .btn { padding: 9px 20px; font-size: 14px; min-height: 38px; }
.nav-toggle { display: none; flex-direction: column; gap: 5px; cursor: pointer; padding: 4px; }
.nav-toggle span { display: block; width: 24px; height: 2px; background: var(--color-text); border-radius: 2px; transition: all 0.3s; }

/* ===== Dropdown Menu ===== */
.nav-item { position: relative; display: flex; align-items: center; }
.nav-link { font-size: 15px; color: #374151; font-weight: 500; transition: color 0.2s; cursor: pointer; display: flex; align-items: center; gap: 3px; user-select: none; }
.nav-item:hover .nav-link { color: var(--color-primary); }
.dropdown-arrow { font-size: 11px; display: inline-block; transition: transform 0.2s; }
.nav-item:hover .dropdown-arrow,
.nav-item.open .dropdown-arrow { transform: rotate(180deg); }
.dropdown-menu {
  position: absolute;
  top: calc(100% + 16px);
  left: 50%;
  transform: translateX(-50%) translateY(-6px);
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: 0 8px 28px rgba(0,0,0,0.12);
  min-width: 160px;
  padding: 6px 0;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.2s, transform 0.2s, visibility 0.2s;
  z-index: 200;
}
.dropdown-menu::before {
  content: '';
  position: absolute;
  top: -6px; left: 50%;
  transform: translateX(-50%);
  border: 6px solid transparent;
  border-top: 0;
  border-bottom-color: var(--color-border);
}
.dropdown-menu::after {
  content: '';
  position: absolute;
  top: -5px; left: 50%;
  transform: translateX(-50%);
  border: 6px solid transparent;
  border-top: 0;
  border-bottom-color: #fff;
}
.nav-item:hover .dropdown-menu { opacity: 1; visibility: visible; transform: translateX(-50%) translateY(0); }
.dropdown-menu a { display: block; padding: 9px 20px; font-size: 14px; color: #374151; font-weight: 400; white-space: nowrap; transition: background 0.15s, color 0.15s; }
.dropdown-menu a:hover { background: var(--color-bg); color: var(--color-primary); }
.dropdown-menu .dropdown-all { border-top: 1px solid var(--color-border); margin-top: 4px; padding-top: 10px; color: var(--color-primary); font-weight: 500; }
.dropdown-menu .dropdown-all:hover { background: rgba(229,164,20,0.06); }

/* ===== Hero ===== */
.page-hero {
  margin-top: 64px;
  background: linear-gradient(135deg, #0F172A 0%, #1E293B 60%, #111827 100%);
  padding: 80px 0 70px;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.page-hero::before {
  content: '';
  position: absolute;
  bottom: -80px; left: 50%;
  transform: translateX(-50%);
  width: 800px; height: 300px;
  background: radial-gradient(ellipse, rgba(229,164,20,0.12) 0%, transparent 70%);
  pointer-events: none;
}
.page-hero .en-sub {
  font-size: 13px; color: var(--color-primary); font-weight: 600;
  letter-spacing: 3px; text-transform: uppercase; display: block; margin-bottom: 14px;
}
.page-hero h1 { font-size: 52px; font-weight: 700; color: #fff; line-height: 1.2; margin-bottom: 18px; }
.page-hero p { font-size: 18px; color: rgba(255,255,255,0.72); max-width: 640px; margin: 0 auto 32px; }
.page-hero .hero-actions { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }

/* ===== About Intro ===== */
.about-intro .container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}
.about-intro-text .section-label {
  font-size: 13px; color: var(--color-primary); font-weight: 600;
  letter-spacing: 2px; text-transform: uppercase; display: block; margin-bottom: 12px;
}
.about-intro-text h2 { font-size: 40px; font-weight: 700; line-height: 1.25; margin-bottom: 28px; }
.about-intro-text h2 span { color: var(--color-primary); }
.about-intro-text p { font-size: 16px; color: var(--color-text-muted); line-height: 1.8; margin-bottom: 18px; }
.about-intro-text p:last-of-type { margin-bottom: 32px; }
.about-intro-img img {
  width: 100%;
  border-radius: 16px;
  box-shadow: 0 20px 60px rgba(0,0,0,0.12);
}

/* ===== History Image ===== */
.history-section { padding: 0; background: var(--color-bg); }
.history-section .history-img { width: 100%; max-height: 480px; object-fit: cover; }
.history-section .container { padding: 60px 30px; }
.history-section img.full-img {
  max-width: var(--max-width);
  width: 100%;
  margin: 0 auto;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

/* ===== Industry ===== */
.industry-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 48px;
  align-items: center;
}
.industry-text {}
.industry-text p { font-size: 16px; color: var(--color-text-muted); line-height: 1.8; margin-bottom: 16px; }
.industry-tags { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 28px; }
.industry-tag {
  padding: 8px 18px;
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: 24px;
  font-size: 14px;
  color: var(--color-text);
  font-weight: 500;
  transition: all 0.2s;
  cursor: default;
}
.industry-tag:hover { border-color: var(--color-primary); color: var(--color-primary); background: rgba(229,164,20,0.06); }
.industry-visual { text-align: center; }
.industry-visual .stat-cards { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.stat-card {
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: 12px;
  padding: 28px 20px;
  text-align: center;
  transition: all 0.3s;
}
.stat-card:hover { border-color: var(--color-primary); box-shadow: var(--shadow); }
.stat-card .number { font-size: 44px; font-weight: 700; color: var(--color-primary); line-height: 1.1; }
.stat-card .unit { font-size: 20px; }
.stat-card .label { font-size: 14px; color: var(--color-text-muted); margin-top: 6px; }

/* ===== Data Ecosystem ===== */
.ecosystem-content { text-align: center; }
.ecosystem-content p { font-size: 16px; color: var(--color-text-muted); max-width: 680px; margin: 0 auto 16px; line-height: 1.8; }
.ecosystem-content img {
  max-width: 900px;
  width: 100%;
  margin: 40px auto 0;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

/* ===== Tech Partners ===== */
.tech-section {}
.tech-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 56px; align-items: center; }
.tech-text p { font-size: 16px; color: var(--color-text-muted); line-height: 1.8; margin-bottom: 16px; }
.tech-logos { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.tech-logo-item {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 64px;
  font-size: 13px;
  font-weight: 600;
  color: var(--color-text-muted);
  text-align: center;
  transition: all 0.2s;
}
.tech-logo-item:hover { border-color: var(--color-primary); background: rgba(229,164,20,0.04); }
.tech-logo-item img { max-height: 32px; width: auto; margin: 0 auto; }
.tech-img-full {
  width: 100%;
  border-radius: 12px;
  box-shadow: var(--shadow);
}

/* ===== Methodology ===== */
.method-tabs { display: flex; gap: 0; border-bottom: 2px solid var(--color-border); margin-bottom: 40px; }
.method-tab {
  padding: 14px 28px;
  font-size: 16px;
  font-weight: 500;
  color: var(--color-text-muted);
  cursor: pointer;
  border-bottom: 2px solid transparent;
  margin-bottom: -2px;
  transition: all 0.2s;
}
.method-tab.active { color: var(--color-primary); border-bottom-color: var(--color-primary); }
.method-panels {}
.method-panel { display: none; }
.method-panel.active { display: grid; grid-template-columns: 1fr 1fr; gap: 48px; align-items: center; }
.method-panel-text h3 { font-size: 28px; font-weight: 700; color: var(--color-text); margin-bottom: 20px; }
.method-panel-text p { font-size: 16px; color: var(--color-text-muted); line-height: 1.8; margin-bottom: 14px; }
.method-panel-img img {
  width: 100%;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

/* ===== Team ===== */
.team-section {
  background: linear-gradient(135deg, #1F2937 0%, #111827 100%);
  padding: 80px 0;
  text-align: center;
}
.team-section .section-label {
  font-size: 13px; color: var(--color-primary); font-weight: 600;
  letter-spacing: 2px; text-transform: uppercase; display: block; margin-bottom: 12px;
}
.team-section h2 { font-size: 40px; font-weight: 700; color: #fff; margin-bottom: 16px; }
.team-section .team-en { font-size: 15px; color: rgba(255,255,255,0.45); font-style: italic; margin-bottom: 24px; }
.team-section p { font-size: 16px; color: rgba(255,255,255,0.72); max-width: 640px; margin: 0 auto 32px; line-height: 1.8; }

/* ===== Partners ===== */
.partners-section {}
.partners-section img {
  max-width: 960px;
  width: 100%;
  margin: 0 auto;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

/* ===== Honors ===== */
.honors-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}
.honor-item {
  border: 1px solid var(--color-border);
  border-radius: 12px;
  padding: 20px;
  text-align: center;
  transition: all 0.3s;
}
.honor-item:hover { border-color: var(--color-primary); box-shadow: var(--shadow); transform: translateY(-3px); }
.honor-item img { width: 100%; border-radius: var(--radius); }

/* ===== CTA Section ===== */
.cta-section {
  background: linear-gradient(135deg, #E5A414 0%, #c8900f 100%);
  padding: 80px 0;
  text-align: center;
}
.cta-section h2 { font-size: 40px; font-weight: 700; color: #fff; margin-bottom: 16px; }
.cta-section p { font-size: 18px; color: rgba(255,255,255,0.85); margin-bottom: 36px; max-width: 560px; margin-left: auto; margin-right: auto; }
.cta-actions { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }
.btn-cta-white { background: #fff; color: var(--color-primary); border: 2px solid #fff; padding: 14px 36px; font-size: 16px; font-weight: 600; border-radius: var(--radius); cursor: pointer; transition: all 0.2s; display: inline-flex; align-items: center; justify-content: center; }
.btn-cta-white:hover { background: transparent; color: #fff; }
.btn-cta-outline { background: transparent; color: #fff; border: 2px solid rgba(255,255,255,0.7); padding: 14px 36px; font-size: 16px; font-weight: 600; border-radius: var(--radius); cursor: pointer; transition: all 0.2s; display: inline-flex; align-items: center; justify-content: center; }
.btn-cta-outline:hover { background: rgba(255,255,255,0.15); }

/* ===== Footer ===== */
.site-footer {
  background: #111827;
  color: rgba(255,255,255,0.65);
  padding: 48px 0 24px;
}
.footer-inner {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 48px;
  padding-bottom: 40px;
  border-bottom: 1px solid rgba(255,255,255,0.08);
}
.footer-brand img { height: 44px; margin-bottom: 16px; filter: brightness(10); opacity: 0.8; }
.footer-brand p { font-size: 14px; line-height: 1.7; max-width: 300px; }
.footer-contact { margin-top: 20px; }
.footer-contact a { font-size: 15px; color: rgba(255,255,255,0.8); display: block; margin-bottom: 8px; }
.footer-contact a:hover { color: var(--color-primary); }
.footer-col h4 { font-size: 15px; font-weight: 600; color: rgba(255,255,255,0.9); margin-bottom: 16px; }
.footer-col ul li { margin-bottom: 10px; }
.footer-col ul li a { font-size: 14px; color: rgba(255,255,255,0.55); transition: color 0.2s; }
.footer-col ul li a:hover { color: var(--color-primary); }
.footer-bottom { padding-top: 20px; text-align: center; font-size: 13px; color: rgba(255,255,255,0.35); }
.footer-bottom a { color: rgba(255,255,255,0.45); margin: 0 8px; }
.footer-bottom a:hover { color: var(--color-primary); }

/* ===== Responsive ===== */
@media (max-width: 1024px) {
  .about-intro .container { gap: 40px; }
  .tech-grid { gap: 36px; }
  .honors-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-inner { grid-template-columns: 1fr 1fr; }
  .footer-brand { grid-column: 1 / -1; }
}

@media (max-width: 900px) {
  .section { padding: 60px 0; }
  .about-intro .container { grid-template-columns: 1fr; gap: 40px; }
  .industry-grid { grid-template-columns: 1fr; gap: 40px; }
  .tech-grid { grid-template-columns: 1fr; }
  .method-panel.active { grid-template-columns: 1fr; gap: 32px; }
  .page-hero h1 { font-size: 40px; }
}

@media (max-width: 768px) {
  .section { padding: 56px 0; }
  .container { padding: 0 16px; }
  .page-hero { padding: 64px 0 56px; }
  .page-hero h1 { font-size: 30px; }
  .page-hero p { font-size: 16px; }

  .header-nav { display: none; position: absolute; top: 64px; left: 0; right: 0; background: #fff; flex-direction: column; padding: 16px 24px; gap: 0; border-bottom: 1px solid var(--color-border); box-shadow: 0 8px 24px rgba(0,0,0,0.08); }
  .header-nav.open { display: flex; }
  .header-nav > a { padding: 12px 0; border-bottom: 1px solid var(--color-border); width: 100%; display: block; }
  .header-cta .btn-ghost { display: none; }
  .nav-toggle { display: flex; }

  /* 移动端下拉 */
  .nav-item { width: 100%; flex-direction: column; align-items: flex-start; border-bottom: 1px solid var(--color-border); }
  .nav-link { padding: 12px 0; width: 100%; justify-content: space-between; }
  .nav-item:hover .nav-link { color: #374151; }
  .nav-item:hover .dropdown-menu { opacity: 1; visibility: visible; transform: none; }
  .dropdown-menu { position: static; opacity: 1; visibility: visible; transform: none; box-shadow: none; border: none; border-radius: 0; padding: 0 0 8px 0; min-width: 0; width: 100%; display: none; }
  .dropdown-menu::before, .dropdown-menu::after { display: none; }
  .nav-item.open > .nav-link { color: var(--color-primary); }
  .nav-item.open .dropdown-menu { display: block; }
  .dropdown-menu a { padding: 9px 12px; border-bottom: none; color: #6B7280; }
  .dropdown-menu a:hover { background: none; color: var(--color-primary); }
  .dropdown-menu .dropdown-all { border-top: none; margin-top: 0; }

  .about-intro-text h2 { font-size: 28px; }
  .industry-visual .stat-cards { grid-template-columns: repeat(2, 1fr); }
  .method-tabs { overflow-x: auto; }
  .method-tab { padding: 12px 18px; font-size: 14px; white-space: nowrap; }
  .team-section h2 { font-size: 28px; }
  .honors-grid { grid-template-columns: repeat(2, 1fr); }
  .section-header h2 { font-size: 26px; }
  .cta-section h2 { font-size: 28px; }
  .cta-actions { flex-direction: column; align-items: center; }
  .btn-cta-white, .btn-cta-outline { width: 100%; max-width: 300px; }
  .footer-inner { grid-template-columns: 1fr; gap: 32px; }
  .tech-logos { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 480px) {
  .page-hero h1 { font-size: 26px; }
  .page-hero .hero-actions { flex-direction: column; align-items: center; }
  .honors-grid { grid-template-columns: 1fr 1fr; gap: 12px; }
  .industry-tags { gap: 8px; }
}