:root {
  --bg: #ffffff;
  --bg-muted: #f8f9fa;
  --bg-dark: #0c0c0c;
  --text: #1a1a1a;
  --text-secondary: #5c5c5c;
  --text-muted: #8c8c8c;
  --border: #e8e8e8;
  --accent: #1a56db;
  --accent-hover: #1344b5;
  --radius: 8px;
  --header-h: 64px;
  --max-w: 1080px;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--header-h);
}

body {
  font-family: "PingFang SC", "Microsoft YaHei", -apple-system, BlinkMacSystemFont, sans-serif;
  font-size: 15px;
  line-height: 1.7;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}

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

.container {
  width: 100%;
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 24px;
}

/* Header */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: var(--header-h);
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.header.scrolled {
  border-color: var(--border);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
}

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

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
}

.brand-mark {
  flex-shrink: 0;
  font-size: 15px;
  font-weight: 600;
  color: var(--bg);
  background: var(--text);
  padding: 6px 12px;
  border-radius: 6px;
  letter-spacing: 0.02em;
}

.brand-full {
  font-size: 14px;
  font-weight: 500;
  color: var(--text-secondary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.nav {
  display: flex;
  gap: 32px;
}

.nav a {
  font-size: 14px;
  color: var(--text-secondary);
  transition: color 0.15s;
}

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

.menu-btn {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 6px;
  width: 36px;
  height: 36px;
  padding: 8px;
  background: none;
  border: none;
  cursor: pointer;
}

.menu-btn span {
  display: block;
  height: 2px;
  background: var(--text);
  border-radius: 1px;
  transition: transform 0.2s, opacity 0.2s;
}

.menu-btn.open span:first-child {
  transform: translateY(4px) rotate(45deg);
}

.menu-btn.open span:last-child {
  transform: translateY(-4px) rotate(-45deg);
}

/* Hero */
.hero {
  padding: calc(var(--header-h) + 80px) 0 80px;
  background: var(--bg-dark);
  color: #fff;
}

.hero-inner {
  max-width: 640px;
}

.hero-label {
  font-size: 13px;
  color: rgba(255, 255, 255, 0.5);
  letter-spacing: 0.08em;
  margin-bottom: 20px;
}

.hero h1 {
  font-size: clamp(28px, 5vw, 42px);
  font-weight: 600;
  line-height: 1.35;
  letter-spacing: -0.02em;
  margin-bottom: 20px;
}

.hero-lead {
  font-size: 16px;
  line-height: 1.8;
  color: rgba(255, 255, 255, 0.65);
  margin-bottom: 32px;
}

.hero-link {
  display: inline-block;
  font-size: 14px;
  font-weight: 500;
  color: #fff;
  padding-bottom: 2px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.35);
  transition: border-color 0.15s, color 0.15s;
}

.hero-link:hover {
  border-color: #fff;
  color: #fff;
}

/* Sections */
.section {
  padding: 80px 0;
}

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

.section-head {
  margin-bottom: 40px;
}

.section-head h2 {
  font-size: 22px;
  font-weight: 600;
  letter-spacing: -0.01em;
}

/* About */
.about-layout {
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  gap: 48px;
  align-items: start;
}

.prose p {
  color: var(--text-secondary);
  margin-bottom: 16px;
}

.prose p:last-child {
  margin-bottom: 0;
}

.facts {
  display: flex;
  flex-direction: column;
  gap: 0;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--bg);
}

.fact {
  padding: 18px 20px;
  border-bottom: 1px solid var(--border);
}

.fact:last-child {
  border-bottom: none;
}

.fact dt {
  font-size: 12px;
  color: var(--text-muted);
  margin-bottom: 4px;
}

.fact dd {
  font-size: 14px;
  color: var(--text);
}

/* Business cards */
.cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

.card {
  padding: 24px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: border-color 0.15s;
}

.card:hover {
  border-color: #ccc;
}

.card h3 {
  font-size: 15px;
  font-weight: 600;
  margin-bottom: 8px;
}

.card p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.65;
}

.cards .card:last-child {
  grid-column: span 1;
}

/* Contact */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.contact-item {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 22px 24px;
  background: var(--bg);
}

.contact-label {
  font-size: 12px;
  color: var(--text-muted);
}

.contact-value {
  font-size: 15px;
  color: var(--text);
}

.contact-note {
  margin-top: 16px;
  font-size: 13px;
  color: var(--text-muted);
}

/* Footer */
.footer {
  padding: 28px 0;
  background: var(--bg-dark);
  color: rgba(255, 255, 255, 0.45);
  font-size: 13px;
}

.footer-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
}

.footer-beian {
  color: rgba(255, 255, 255, 0.45);
  transition: color 0.15s;
}

.footer-beian:hover {
  color: rgba(255, 255, 255, 0.8);
}

/* Responsive */
@media (max-width: 768px) {
  .brand-full {
    display: none;
  }

  .menu-btn {
    display: flex;
  }

  .nav {
    display: none;
    position: fixed;
    top: var(--header-h);
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    padding: 8px 0 16px;
    background: rgba(255, 255, 255, 0.97);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
  }

  .nav.open {
    display: flex;
  }

  .nav a {
    padding: 12px 24px;
    font-size: 15px;
  }

  .hero {
    padding: calc(var(--header-h) + 56px) 0 56px;
  }

  .section {
    padding: 56px 0;
  }

  .about-layout {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .cards {
    grid-template-columns: 1fr;
  }

  .contact-grid {
    grid-template-columns: 1fr;
  }

  .footer-row {
    flex-direction: column;
    text-align: center;
  }
}

@media (min-width: 769px) and (max-width: 960px) {
  .cards {
    grid-template-columns: repeat(2, 1fr);
  }
}