:root {
  --color-primary: #2563eb;
  --color-primary-dark: #1d4ed8;
  --color-primary-light: #dbeafe;
  --color-accent: #0ea5e9;
  --color-text: #0f172a;
  --color-text-muted: #64748b;
  --color-bg: #ffffff;
  --color-bg-soft: #f8fafc;
  --color-bg-dark: #0f172a;
  --color-border: #e2e8f0;
  --shadow-sm: 0 1px 2px rgb(15 23 42 / 0.05);
  --shadow-md: 0 4px 24px rgb(15 23 42 / 0.08);
  --shadow-lg: 0 20px 50px rgb(15 23 42 / 0.12);
  --radius: 16px;
  --radius-sm: 10px;
  --max-width: 1120px;
  --header-height: 72px;
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: 'Inter', 'Noto Sans SC', system-ui, -apple-system, sans-serif;
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.6;
  overflow-x: hidden;
}

body.menu-open {
  overflow: hidden;
}

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

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

ul {
  list-style: none;
}

.container {
  width: min(100% - 2rem, var(--max-width));
  margin-inline: auto;
}

/* Header */
.site-header {
  position: fixed;
  inset: 0 0 auto;
  z-index: 100;
  height: var(--header-height);
  background: rgb(255 255 255 / 0.88);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.site-header.scrolled {
  border-color: var(--color-border);
  box-shadow: var(--shadow-sm);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  gap: 1rem;
}

.brand {
  display: flex;
  align-items: center;
  font-weight: 700;
  font-size: 1.125rem;
  color: var(--color-primary);
}

.nav-desktop {
  display: none;
  align-items: center;
  gap: 2rem;
}

.nav-desktop a {
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--color-text-muted);
  transition: color 0.15s;
}

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

.nav-desktop a:focus-visible,
.nav-mobile a:focus-visible,
.lang-toggle button:focus-visible,
.menu-toggle:focus-visible,
.btn:focus-visible,
.footer-links a:focus-visible,
.contact-list a:focus-visible,
.footer-beian a:focus-visible,
.brand:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.lang-toggle {
  display: flex;
  padding: 3px;
  background: var(--color-bg-soft);
  border: 1px solid var(--color-border);
  border-radius: 999px;
}

.lang-toggle button {
  padding: 0.3rem 0.75rem;
  border: none;
  background: transparent;
  font: inherit;
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--color-text-muted);
  border-radius: 999px;
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
}

.lang-toggle button.active {
  background: var(--color-bg);
  color: var(--color-primary);
  box-shadow: var(--shadow-sm);
}

.menu-toggle {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  padding: 8px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-bg);
  cursor: pointer;
}

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

.menu-toggle.open span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.menu-toggle.open span:nth-child(2) {
  opacity: 0;
}

.menu-toggle.open span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

.nav-mobile {
  display: none;
  position: fixed;
  inset: var(--header-height) 0 0;
  z-index: 99;
  background: var(--color-bg);
  padding: 1.5rem;
  border-top: 1px solid var(--color-border);
}

.nav-mobile.open {
  display: block;
}

.nav-mobile a {
  display: block;
  padding: 0.875rem 0;
  font-weight: 500;
  color: var(--color-text);
  border-bottom: 1px solid var(--color-border);
}

/* Hero */
.hero {
  padding: calc(var(--header-height) + 4rem) 0 5rem;
  background:
    radial-gradient(ellipse 80% 60% at 50% -10%, rgb(37 99 235 / 0.12), transparent),
    linear-gradient(180deg, var(--color-bg-soft) 0%, var(--color-bg) 100%);
}

.hero-grid {
  display: grid;
  gap: 3rem;
  align-items: center;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.375rem 0.875rem;
  margin-bottom: 1.25rem;
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--color-primary);
  background: var(--color-primary-light);
  border-radius: 999px;
}

.hero-badge::before {
  content: '';
  width: 6px;
  height: 6px;
  background: var(--color-primary);
  border-radius: 50%;
}

.hero h1 {
  font-size: clamp(2rem, 5vw, 3.25rem);
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin-bottom: 1.25rem;
}

.hero h1 em {
  font-style: normal;
  color: var(--color-primary);
}

.hero-desc {
  font-size: 1.125rem;
  color: var(--color-text-muted);
  max-width: 540px;
  margin-bottom: 2rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.875rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  font: inherit;
  font-size: 0.9375rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  border: none;
  cursor: pointer;
  transition: transform 0.15s, box-shadow 0.15s, background 0.15s;
}

.btn-primary {
  color: #fff;
  background: var(--color-primary);
  box-shadow: 0 4px 14px rgb(37 99 235 / 0.35);
}

.btn-primary:hover {
  background: var(--color-primary-dark);
  transform: translateY(-1px);
}

.btn-outline {
  color: var(--color-text);
  background: var(--color-bg);
  border: 1px solid var(--color-border);
}

.btn-outline:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.hero-visual {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  align-items: stretch;
}

.hero-card {
  display: flex;
  flex-direction: column;
  height: 100%;
  padding: 1.5rem;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-md);
}

.hero-card-icon {
  width: 44px;
  height: 44px;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1rem;
  font-size: 1.25rem;
  background: var(--color-primary-light);
  border-radius: 12px;
}

.hero-card h3 {
  font-size: 1rem;
  font-weight: 700;
  line-height: 1.4;
  margin-bottom: 0.5rem;
}

.hero-card p {
  flex: 1;
  font-size: 0.875rem;
  line-height: 1.6;
  color: var(--color-text-muted);
}

/* Sections */
section {
  padding: 5rem 0;
  scroll-margin-top: var(--header-height);
}

.section-header {
  margin-bottom: 3rem;
}

.section-label {
  display: inline-block;
  margin-bottom: 0.75rem;
  font-size: 0.8125rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-primary);
}

.section-title {
  font-size: clamp(1.75rem, 3vw, 2.25rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 1rem;
}

.section-desc {
  font-size: 1.0625rem;
  color: var(--color-text-muted);
  max-width: 640px;
  margin-bottom: 0;
}

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

/* About */
.about-grid {
  display: grid;
  gap: 2.5rem;
  align-items: stretch;
}

.about-stats {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
  align-items: stretch;
}

.stat-card {
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-height: 100%;
  padding: 1.5rem;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
}

.stat-card strong {
  display: block;
  font-size: 1.75rem;
  font-weight: 800;
  line-height: 1.2;
  color: var(--color-primary);
  margin-bottom: 0.375rem;
}

.stat-card span {
  font-size: 0.875rem;
  line-height: 1.5;
  color: var(--color-text-muted);
}

.about-text {
  display: flex;
  flex-direction: column;
  justify-content: center;
  height: 100%;
}

.about-text p {
  margin-bottom: 1rem;
  color: var(--color-text-muted);
  line-height: 1.75;
}

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

/* Products */
.products-grid {
  display: grid;
  gap: 1.5rem;
  align-items: stretch;
}

.product-card {
  display: flex;
  flex-direction: column;
  height: 100%;
  padding: 2rem;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  transition: box-shadow 0.2s, border-color 0.2s;
}

.product-card:hover {
  box-shadow: var(--shadow-md);
  border-color: rgb(37 99 235 / 0.25);
}

.product-card.featured {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
  border-color: transparent;
  color: #fff;
}

.product-card.featured .product-tag,
.product-card.featured h3,
.product-card.featured p,
.product-card.featured li {
  color: rgb(255 255 255 / 0.85);
}

.product-card.featured h3 {
  color: #fff;
}

.product-card.featured .product-tag {
  background: rgb(255 255 255 / 0.15);
  color: #fff;
}

.product-tag {
  display: inline-block;
  padding: 0.25rem 0.625rem;
  margin-bottom: 1rem;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-primary);
  background: var(--color-primary-light);
  border-radius: 6px;
}

.product-card h3 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
}

.product-card p {
  font-size: 0.9375rem;
  color: var(--color-text-muted);
  line-height: 1.7;
  margin-bottom: 1.25rem;
}

.product-features {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: auto;
}

.product-features li {
  padding: 0.375rem 0.75rem;
  font-size: 0.8125rem;
  color: var(--color-text-muted);
  background: var(--color-bg-soft);
  border-radius: 999px;
}

.product-card.featured .product-features li {
  background: rgb(255 255 255 / 0.12);
}

/* Apps */
.apps-grid {
  display: grid;
  gap: 1rem;
  align-items: stretch;
}

.app-item {
  display: flex;
  gap: 1rem;
  align-items: flex-start;
  height: 100%;
  padding: 1.25rem 1.5rem;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  transition: border-color 0.15s;
}

.app-item:hover {
  border-color: var(--color-primary);
}

.app-icon {
  flex-shrink: 0;
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.375rem;
  background: var(--color-bg-soft);
  border-radius: 12px;
}

.app-item h4 {
  font-size: 1rem;
  font-weight: 600;
  line-height: 1.4;
  margin-bottom: 0.375rem;
}

.app-item p {
  font-size: 0.875rem;
  line-height: 1.6;
  color: var(--color-text-muted);
}

.app-body {
  flex: 1;
  min-width: 0;
}

/* Values */
.values-grid {
  display: grid;
  gap: 1.5rem;
  align-items: stretch;
}

.value-card {
  display: flex;
  flex-direction: column;
  height: 100%;
  padding: 1.75rem;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
}

.value-card .value-icon {
  flex-shrink: 0;
  font-size: 1.5rem;
  margin-bottom: 1rem;
}

.value-card h3 {
  font-size: 1.0625rem;
  font-weight: 700;
  line-height: 1.4;
  margin-bottom: 0.5rem;
}

.value-card p {
  flex: 1;
  font-size: 0.9375rem;
  line-height: 1.7;
  color: var(--color-text-muted);
}

/* Contact / Footer */
.site-footer {
  background: var(--color-bg-dark);
  color: #fff;
  padding: 4rem 0 2rem;
}

.footer-grid {
  display: grid;
  gap: 2.5rem;
  align-items: start;
  margin-bottom: 3rem;
}

.footer-brand {
  margin-bottom: 1rem;
}

.footer-brand span {
  font-size: 1.25rem;
  font-weight: 700;
}

.footer-tagline {
  color: rgb(255 255 255 / 0.6);
  font-size: 0.9375rem;
  margin-bottom: 1.5rem;
}

.contact-list li {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  margin-bottom: 0.875rem;
  font-size: 0.9375rem;
  color: rgb(255 255 255 / 0.75);
}

.contact-list svg {
  flex-shrink: 0;
  width: 18px;
  height: 18px;
  margin-top: 3px;
  opacity: 0.7;
}

.contact-list a {
  color: rgb(255 255 255 / 0.85);
  transition: color 0.15s;
}

.contact-list a:hover {
  color: #60a5fa;
}

.footer-links h4 {
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: 1rem;
  color: rgb(255 255 255 / 0.5);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.footer-links a {
  display: block;
  padding: 0.375rem 0;
  font-size: 0.9375rem;
  color: rgb(255 255 255 / 0.75);
  transition: color 0.15s;
}

.footer-links a:hover {
  color: #60a5fa;
}

.footer-bottom {
  padding-top: 2rem;
  border-top: 1px solid rgb(255 255 255 / 0.1);
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  text-align: center;
  font-size: 0.8125rem;
  color: rgb(255 255 255 / 0.45);
}

.footer-beian a {
  color: rgb(255 255 255 / 0.55);
  transition: color 0.15s;
}

.footer-beian a:hover {
  color: #60a5fa;
}

/* Responsive */
@media (min-width: 640px) {
  .about-stats {
    grid-template-columns: repeat(4, 1fr);
  }

  .apps-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .app-item:last-child:nth-child(odd) {
    grid-column: 1 / -1;
  }
}

@media (min-width: 768px) {
  .menu-toggle {
    display: none;
  }

  .nav-desktop {
    display: flex;
  }

  .hero-grid {
    grid-template-columns: 1.1fr 0.9fr;
  }

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

  .products-grid {
    grid-template-columns: repeat(3, 1fr);
  }

  .values-grid {
    grid-template-columns: repeat(3, 1fr);
  }

  .footer-grid {
    grid-template-columns: 1.5fr 1fr;
    align-items: start;
  }
}

@media (max-width: 767px) {
  .hero-visual {
    grid-template-columns: 1fr;
  }
}