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

:root {
  --dark: #191c1f;
  --white: #ffffff;
  --surface: #f4f4f4;
  --grey-20: #c9c9cd;
  --grey-mid: #505a63;
  --grey-cool: #8d969e;
  --blue: #494fdf;
  --teal: #00a87e;
  --danger: #e23b4a;
  --pill: 9999px;
  --radius-sm: 12px;
  --radius-card: 20px;
  --transition: 0.25s ease;
  --font-display: "Inter", "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
  --font-body: "Inter", "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 72px;
}

body {
  font-family: var(--font-body);
  font-size: 16px;
  font-weight: 400;
  line-height: 1.5;
  letter-spacing: 0.24px;
  color: var(--dark);
  background: var(--white);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

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

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 40px;
}

.btn {
  display: inline-block;
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 500;
  line-height: 1.4;
  letter-spacing: normal;
  padding: 14px 32px;
  border-radius: var(--pill);
  border: 2px solid transparent;
  cursor: pointer;
  transition: opacity var(--transition);
  text-align: center;
}
.btn:hover { opacity: 0.85; }
.btn:focus-visible { outline: 0 0 0 0.125rem var(--blue); }

.btn-primary {
  background: var(--dark);
  color: var(--white);
  border-color: var(--dark);
}
.btn-secondary {
  background: var(--surface);
  color: #000000;
  border-color: var(--surface);
}
.btn-outlined {
  background: transparent;
  color: var(--dark);
  border-color: var(--dark);
}
.btn-ghost {
  background: rgba(244,244,244,0.1);
  color: var(--surface);
  border-color: var(--surface);
}
.btn-sm {
  font-size: 14px;
  padding: 10px 24px;
}

.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(255,255,255,0.96);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  transition: background var(--transition);
}
.header.scrolled {
  background: rgba(255,255,255,0.98);
}

.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 40px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.logo {
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 700;
  color: var(--dark);
  letter-spacing: -0.4px;
}

.nav-desktop {
  display: flex;
  gap: 4px;
}
.nav-link {
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 500;
  line-height: 1.4;
  color: var(--dark);
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  transition: opacity var(--transition);
}
.nav-link:hover { opacity: 0.6; }
.nav-link.active { opacity: 0.6; }

.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.lang-toggle {
  display: flex;
  align-items: center;
  gap: 6px;
  background: var(--surface);
  border: none;
  cursor: pointer;
  padding: 8px 14px;
  border-radius: var(--pill);
  font-family: var(--font-display);
  font-size: 13px;
  font-weight: 600;
  color: var(--dark);
  letter-spacing: 0.5px;
  transition: opacity var(--transition);
}
.lang-toggle:hover { opacity: 0.7; }

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
  color: var(--dark);
  border-radius: var(--radius-sm);
}

.nav-mobile {
  display: none;
  padding: 8px 40px 24px;
  flex-direction: column;
  gap: 2px;
  background: var(--white);
}
.nav-mobile.open { display: flex; }
.nav-link-mobile {
  display: block;
  padding: 14px 0;
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 500;
  color: var(--dark);
  border-bottom: 1px solid var(--surface);
  transition: opacity var(--transition);
}
.nav-link-mobile:hover { opacity: 0.6; }

.hero {
  margin-top: 72px;
  background: var(--white);
  padding: 88px 40px 120px;
  display: flex;
  justify-content: center;
}
.hero-inner {
  max-width: 900px;
  text-align: center;
}
.hero-eyebrow {
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 500;
  letter-spacing: 0.16px;
  color: var(--grey-mid);
  margin-bottom: 24px;
}
.hero-title {
  font-family: var(--font-display);
  font-size: 80px;
  font-weight: 500;
  line-height: 1.0;
  letter-spacing: -0.8px;
  color: var(--dark);
  margin-bottom: 32px;
}
.hero-subtitle {
  font-family: var(--font-body);
  font-size: 18px;
  font-weight: 400;
  line-height: 1.56;
  letter-spacing: -0.09px;
  color: var(--grey-mid);
  max-width: 600px;
  margin: 0 auto 48px;
}
.hero-actions {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

.section {
  padding: 120px 0;
}

.section-dark {
  background: var(--dark);
  color: var(--white);
}
.section-light {
  background: var(--white);
}

.display-heading {
  font-family: var(--font-display);
  font-size: 48px;
  font-weight: 500;
  line-height: 1.21;
  letter-spacing: -0.48px;
  color: var(--white);
  margin-bottom: 24px;
}
.display-heading.dark {
  color: var(--dark);
}

.body-large {
  font-family: var(--font-body);
  font-size: 18px;
  font-weight: 400;
  line-height: 1.56;
  letter-spacing: -0.09px;
  color: rgba(255,255,255,0.7);
  max-width: 720px;
  margin-bottom: 80px;
}
.body-large.dark-muted {
  color: var(--grey-mid);
}
.about-lead {
  max-width: 800px;
}

.features-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 40px;
  margin-bottom: 88px;
}
.feature-item {
  padding: 0;
}
.feature-icon {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(255,255,255,0.08);
  border-radius: var(--radius-sm);
  margin-bottom: 24px;
}
.feature-title {
  font-family: var(--font-display);
  font-size: 24px;
  font-weight: 500;
  line-height: 1.33;
  color: var(--white);
  margin-bottom: 12px;
}
.feature-text {
  font-size: 16px;
  font-weight: 400;
  line-height: 1.5;
  letter-spacing: 0.24px;
  color: rgba(255,255,255,0.55);
}

.stats-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0;
  border-top: 1px solid rgba(255,255,255,0.1);
  padding-top: 48px;
}
.stat-item {
  text-align: center;
  flex: 1;
}
.stat-number {
  display: block;
  font-family: var(--font-display);
  font-size: 48px;
  font-weight: 500;
  line-height: 1.0;
  letter-spacing: -0.48px;
  color: var(--white);
  margin-bottom: 8px;
}
.stat-label {
  font-size: 14px;
  font-weight: 400;
  letter-spacing: 0.24px;
  color: rgba(255,255,255,0.5);
}
.stat-divider {
  width: 1px;
  height: 48px;
  background: rgba(255,255,255,0.12);
  flex-shrink: 0;
}

.products-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
  margin-top: 64px;
}
.product-card {
  background: var(--surface);
  border-radius: var(--radius-card);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: transform var(--transition);
}
.product-card:hover {
  transform: translateY(-2px);
}
.product-image {
  padding: 20px 20px 0;
  background: var(--surface);
  display: flex;
  align-items: center;
  justify-content: center;
}
.product-image img {
  border-radius: var(--radius-sm);
  width: 100%;
  object-fit: contain;
}
.product-info {
  padding: 24px 28px 28px;
  flex: 1;
}
.product-name {
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 500;
  line-height: 1.4;
  letter-spacing: normal;
  color: var(--dark);
  margin-bottom: 16px;
}
.product-specs {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.product-specs li {
  display: flex;
  align-items: baseline;
  font-size: 14px;
  gap: 8px;
  line-height: 1.5;
}
.spec-label {
  flex-shrink: 0;
  color: var(--grey-cool);
  font-weight: 400;
  min-width: 60px;
  letter-spacing: 0.24px;
}
.spec-label::after {
  content: ":";
}
.spec-value {
  color: var(--dark);
  font-weight: 600;
  letter-spacing: 0.16px;
}

.contact-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.contact-card {
  background: rgba(255,255,255,0.06);
  border-radius: var(--radius-card);
  padding: 40px 32px;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 8px;
}
.contact-icon-wrap {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(255,255,255,0.08);
  border-radius: var(--radius-sm);
  margin-bottom: 12px;
  color: var(--white);
}
.contact-label {
  font-family: var(--font-display);
  font-size: 14px;
  font-weight: 400;
  letter-spacing: 0.24px;
  color: rgba(255,255,255,0.5);
}
.contact-value {
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 500;
  color: var(--white);
  word-break: break-all;
}
.contact-link {
  transition: opacity var(--transition);
}
.contact-link:hover { opacity: 0.7; }

.footer {
  background: var(--dark);
  padding: 32px 0;
  border-top: 1px solid rgba(255,255,255,0.06);
}
.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.footer-brand {
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 700;
  color: var(--white);
  letter-spacing: -0.2px;
}
.footer-copy {
  font-size: 14px;
  color: rgba(255,255,255,0.35);
  letter-spacing: 0.24px;
}

.footer-beian {
  display: flex;
  justify-content: center;
  margin-top: 12px;
}
.beian-row {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  justify-content: center;
}
.beian-link {
  font-size: 13px;
  color: rgba(255,255,255,0.35);
  letter-spacing: 0.24px;
  transition: opacity var(--transition);
}
.beian-link:hover {
  opacity: 0.7;
}
.beian-divider {
  font-size: 13px;
  color: rgba(255,255,255,0.2);
}
.beian-police {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.beian-icon {
  width: 18px;
  height: 18px;
  display: inline-block;
  vertical-align: middle;
}

.back-to-top {
  position: fixed;
  bottom: 32px;
  right: 32px;
  width: 44px;
  height: 44px;
  background: var(--dark);
  color: var(--white);
  border-radius: var(--pill);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition);
  z-index: 999;
  border: 2px solid rgba(255,255,255,0.15);
}
.back-to-top:hover { opacity: 0.85; }
.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

.hide-mobile { display: inline-block; }

@media (max-width: 1024px) {
  .features-row { grid-template-columns: 1fr; gap: 32px; }
  .products-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .container { padding: 0 24px; }
  .header-inner { padding: 0 24px; }
  .nav-mobile { padding: 8px 24px 24px; }
  .nav-desktop { display: none; }
  .mobile-menu-btn { display: block; }
  .hide-mobile { display: none; }

  .hero {
    padding: 64px 24px 80px;
    margin-top: 72px;
  }
  .hero-title {
    font-size: 44px;
    letter-spacing: -0.44px;
  }
  .hero-subtitle { font-size: 16px; }

  .section { padding: 80px 0; }
  .display-heading { font-size: 36px; letter-spacing: -0.36px; }

  .features-row { grid-template-columns: 1fr; gap: 32px; margin-bottom: 56px; }
  .stats-row { flex-direction: column; gap: 32px; padding-top: 40px; }
  .stat-divider { width: 48px; height: 1px; }

  .products-grid { grid-template-columns: 1fr; gap: 20px; }

  .contact-grid { grid-template-columns: 1fr; gap: 16px; }
  .contact-card { padding: 28px 24px; }

  .footer-inner { flex-direction: column; gap: 8px; text-align: center; }
  .back-to-top { bottom: 20px; right: 20px; }
}

@media (max-width: 480px) {
  .container { padding: 0 20px; }
  .header-inner { padding: 0 20px; height: 60px; }
  html { scroll-padding-top: 60px; }
  .hero { margin-top: 60px; padding: 48px 20px 64px; }
  .hero-title { font-size: 36px; letter-spacing: -0.36px; }
  .hero-eyebrow { font-size: 14px; }
  .hero-actions { flex-direction: column; align-items: stretch; }
  .hero-actions .btn { width: 100%; }
  .section { padding: 64px 0; }
  .display-heading { font-size: 30px; letter-spacing: -0.3px; }
  .body-large { font-size: 16px; margin-bottom: 48px; }
  .stat-number { font-size: 36px; }
  .product-info { padding: 20px 22px 24px; }
  .product-name { font-size: 18px; }
}