@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&family=Noto+Sans+SC:wght@400;500;600;700&display=swap');

:root {
  --bg-body: #f8fafc;
  --bg-card: #ffffff;
  --bg-soft: #f1f5f9;
  --bg-muted: #e2e8f0;

  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-tertiary: #64748b;
  --text-muted: #94a3b8;

  --accent-start: #2563eb;
  --accent-end: #7c3aed;
  --accent-gradient: linear-gradient(135deg, #2563eb, #7c3aed);
  --accent-soft: rgba(37, 99, 235, 0.08);
  --accent-hover: #1d4ed8;

  --amber: #f59e0b;
  --emerald: #10b981;
  --rose: #f43f5e;

  --border: #e2e8f0;
  --border-strong: #cbd5e1;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 10px 15px -3px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.08), 0 8px 10px -6px rgba(0, 0, 0, 0.04);
  --shadow-xl: 0 25px 50px -12px rgba(0, 0, 0, 0.15);

  --font-sans: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  --space-xs: 6px;
  --space-sm: 12px;
  --space-md: 24px;
  --space-lg: 40px;
  --space-xl: 64px;
  --space-2xl: 96px;
  --space-3xl: 140px;

  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 20px;
  --radius-full: 9999px;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

[data-zh][data-en] { visibility: hidden; }
body.lang-ready [data-zh][data-en] { visibility: visible; }

a { color: inherit; text-decoration: none; transition: color 0.2s ease; }
img { max-width: 100%; display: block; }
ul, ol { list-style: none; }

h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.3;
  letter-spacing: -0.01em;
}

/* ========= Navigation ========= */
header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.72);
  backdrop-filter: blur(20px) saturate(1.4);
  -webkit-backdrop-filter: blur(20px) saturate(1.4);
  border-bottom: 1px solid var(--border);
}

.main-nav { height: 68px; }

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-md);
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo a {
  display: flex;
  align-items: center;
  gap: 10px;
}

.logo img { height: 30px; width: auto; }

.logo-brand {
  font-size: 20px;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.nav-links {
  display: flex;
  gap: 4px;
  background: var(--bg-soft);
  padding: 4px;
  border-radius: var(--radius-full);
}

.nav-links a {
  padding: 7px 18px;
  font-size: 14px;
  font-weight: 500;
  color: var(--text-tertiary);
  border-radius: var(--radius-full);
  transition: all 0.2s ease;
}

.nav-links a:hover { color: var(--text-primary); background: rgba(255,255,255,0.6); }

.nav-links a.active {
  color: var(--text-primary);
  background: #fff;
  box-shadow: var(--shadow-sm);
}

.nav-right { display: flex; align-items: center; }

.language-switch { position: relative; }

.dropdown-trigger {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 7px 14px;
  font-size: 13px;
  font-weight: 500;
  color: var(--text-tertiary);
  border: 1px solid var(--border);
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: all 0.2s ease;
  background: #fff;
}

.dropdown-trigger:hover {
  color: var(--text-primary);
  border-color: var(--border-strong);
}

.dropdown-content {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  min-width: 150px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-4px);
  transition: all 0.2s ease;
  z-index: 100;
  overflow: hidden;
}

.dropdown:hover .dropdown-content {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.dropdown-content a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 16px;
  font-size: 13px;
  color: var(--text-secondary);
  transition: background 0.15s ease;
}

.dropdown-content a:hover { background: var(--bg-soft); }
.dropdown-content a.active { color: var(--accent-start); font-weight: 600; }

.lang-code {
  font-size: 11px;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

/* ========= Buttons ========= */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  font-size: 14px;
  font-weight: 600;
  font-family: var(--font-sans);
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all 0.25s ease;
  white-space: nowrap;
}

.btn i { font-size: 13px; transition: transform 0.2s ease; }
.btn:hover i { transform: translateX(4px); }

.btn-primary {
  background: var(--accent-gradient);
  color: #fff;
  box-shadow: 0 2px 12px rgba(37, 99, 235, 0.25);
}

.btn-primary:hover {
  box-shadow: 0 6px 24px rgba(37, 99, 235, 0.35);
  transform: translateY(-1px);
}

.btn-secondary {
  background: #fff;
  color: var(--text-secondary);
  border-color: var(--border);
}

.btn-secondary:hover {
  color: var(--text-primary);
  border-color: var(--border-strong);
  box-shadow: var(--shadow-sm);
}

.btn-large { padding: 14px 32px; font-size: 15px; }

/* ========= Section Headers ========= */
.section-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--accent-start);
  margin-bottom: 12px;
}

.section-title {
  font-size: clamp(30px, 3.5vw, 42px);
  color: var(--text-primary);
  margin-bottom: 16px;
  letter-spacing: -0.02em;
}

.section-description {
  font-size: 16px;
  color: var(--text-secondary);
  max-width: 560px;
  line-height: 1.7;
}

/* ========= Footer ========= */
footer {
  background: #0f172a;
  padding: var(--space-2xl) 0 var(--space-lg);
}

.footer-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-md);
}

.footer-main {
  display: grid;
  grid-template-columns: 1.8fr 1fr 1fr 1.2fr;
  gap: var(--space-xl);
  padding-bottom: var(--space-xl);
  border-bottom: 1px solid rgba(255,255,255,0.08);
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: var(--space-sm);
}

.footer-logo img { height: 26px; filter: brightness(1.3); }

.footer-logo-text {
  font-size: 18px;
  font-weight: 700;
  color: #fff;
  letter-spacing: -0.02em;
}

.footer-description {
  font-size: 14px;
  color: #94a3b8;
  line-height: 1.7;
  max-width: 300px;
}

.footer-group-title {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: #475569;
  margin-bottom: var(--space-md);
}

.footer-links-list { display: flex; flex-direction: column; gap: 10px; }

.footer-links-list a {
  font-size: 14px;
  color: #94a3b8;
  transition: color 0.2s ease;
}

.footer-links-list a:hover { color: #fff; }

.footer-contact-item {
  font-size: 13px;
  color: #94a3b8;
  line-height: 1.6;
}

.footer-contact-item strong {
  color: #64748b;
  font-weight: 500;
  font-size: 12px;
}

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: var(--space-lg);
}

.footer-copyright p {
  font-size: 13px;
  color: #475569;
}

.footer-social {
  display: flex;
  gap: 10px;
}

.footer-social-link {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: var(--radius-sm);
  color: #64748b;
  font-size: 15px;
  transition: all 0.2s ease;
}

.footer-social-link:hover {
  color: #fff;
  border-color: rgba(255,255,255,0.2);
  background: rgba(255,255,255,0.05);
}

/* ========= Page Breadcrumb ========= */
.page-breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--text-muted);
  margin-bottom: var(--space-md);
}

.page-breadcrumb a { color: var(--text-tertiary); }
.page-breadcrumb a:hover { color: var(--accent-start); }
.page-breadcrumb i { font-size: 10px; color: var(--text-muted); }

/* ========= Cards (Bento base) ========= */
.bento-card {
  background: #fff;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  padding: 28px;
  transition: all 0.3s ease;
}

.bento-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
}

/* ========= Animations ========= */
[data-animate] {
  opacity: 0;
  transition: opacity 0.6s ease, transform 0.6s ease;
}

[data-animate="fade-in"] { opacity: 0; }
[data-animate="slide-up"] { transform: translateY(30px); }
[data-animate="slide-left"] { transform: translateX(30px); }
[data-animate="slide-right"] { transform: translateX(-30px); }
[data-animate="scale-in"] { transform: scale(0.95); }

[data-animate].animated {
  opacity: 1;
  transform: none;
}

/* ========= Responsive ========= */
@media (max-width: 900px) {
  .nav-links { display: none; }
  .footer-main { grid-template-columns: 1fr 1fr; gap: var(--space-lg); }
}

@media (max-width: 600px) {
  .footer-main { grid-template-columns: 1fr; gap: var(--space-lg); }
  .footer-bottom { flex-direction: column; gap: var(--space-sm); text-align: center; }
}