/* ==========================================================================
   AV Professional Landing Page — Core Stylesheet
   Design System: GSL Layout + Nanpeng Color Scheme + Tech Enhancement
   ==========================================================================

   Color Palette:
   - Primary Dark:    #0a0e1a (深空蓝黑)
   - Background:      #ffffff / #f5f7fa
   - Accent (Gold):   #b8923a
   - Tech Cyan:       #00d4ff (科技青)
   - Tech Blue:       #0a84ff (科技蓝)
   - Text:            #1a1a2e / #6b6b8a
   - Border:          #e0e0e8
   - Glow:            rgba(0, 212, 255, 0.15)

   ========================================================================== */

/* --------------------------------------------------------------------------
   1. CSS Reset & Variables
   -------------------------------------------------------------------------- */

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

:root {
  /* Colors — Base */
  --color-bg: #ffffff;
  --color-surface: #f5f7fa;
  --color-surface-dark: #0a0e1a;
  --color-surface-dark-2: #111827;
  --color-text: #1a1a2e;
  --color-text-secondary: #6b6b8a;
  --color-text-inverse: #ffffff;
  --color-text-inverse-secondary: #94a3b8;
  --color-border: #e0e0e8;
  --color-border-dark: #1e293b;
  --color-link: #1a1a2e;
  --color-link-hover: #00d4ff;

  /* Colors — Accent (Gold, kept for brand consistency) */
  --color-accent: #b8923a;
  --color-accent-hover: #a07e2e;
  --color-accent-light: #f4ecd8;

  /* Colors — Tech (Cyan/Blue for sci-tech feel) */
  --color-tech: #00d4ff;
  --color-tech-hover: #00b8e6;
  --color-tech-light: rgba(0, 212, 255, 0.08);
  --color-tech-blue: #0a84ff;
  --color-tech-glow: rgba(0, 212, 255, 0.15);
  --color-tech-glow-strong: rgba(0, 212, 255, 0.3);

  /* Gradients */
  --gradient-dark: linear-gradient(135deg, #0a0e1a 0%, #111827 50%, #0a0e1a 100%);
  --gradient-tech: linear-gradient(135deg, #0a0e1a 0%, #0d1b2a 40%, #0a1f2e 100%);
  --gradient-accent: linear-gradient(90deg, #b8923a 0%, #00d4ff 100%);
  --gradient-hero-overlay: linear-gradient(180deg, rgba(10,14,26,0.6) 0%, rgba(10,14,26,0.9) 100%);
  --gradient-button-tech: linear-gradient(135deg, #00d4ff 0%, #0a84ff 100%);

  /* Typography */
  --font-sans: "Helvetica Neue", "Arial", "PingFang SC", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  --font-mono: "SF Mono", "Fira Code", "Consolas", monospace;

  /* Spacing */
  --space-xs: 8px;
  --space-sm: 16px;
  --space-md: 24px;
  --space-lg: 40px;
  --space-xl: 64px;
  --space-2xl: 96px;
  --space-3xl: 128px;

  /* Layout */
  --container-max: 1280px;
  --container-padding: 24px;
  --nav-height: 72px;

  /* Transitions */
  --transition-fast: 0.2s ease;
  --transition-base: 0.3s ease;
  --transition-slow: 0.5s ease;
  --transition-tech: 0.4s cubic-bezier(0.4, 0, 0.2, 1);

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 12px 32px rgba(0, 0, 0, 0.12);
  --shadow-tech: 0 0 20px rgba(0, 212, 255, 0.15);
  --shadow-tech-strong: 0 0 30px rgba(0, 212, 255, 0.25), 0 0 60px rgba(0, 212, 255, 0.1);

  /* Grid Pattern */
  --grid-pattern: linear-gradient(rgba(0, 212, 255, 0.03) 1px, transparent 1px),
                   linear-gradient(90deg, rgba(0, 212, 255, 0.03) 1px, transparent 1px);
  --grid-size: 40px;
}

@media (min-width: 768px) {
  :root {
    --container-padding: 40px;
  }
}

@media (min-width: 1025px) {
  :root {
    --container-padding: 64px;
  }
}

/* --------------------------------------------------------------------------
   2. Base Styles
   -------------------------------------------------------------------------- */

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

body {
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  overflow-x: hidden;
}

a {
  color: var(--color-link);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--color-link-hover);
}

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

ul {
  list-style: none;
}

/* --------------------------------------------------------------------------
   3. Layout Utilities
   -------------------------------------------------------------------------- */

.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding-left: var(--container-padding);
  padding-right: var(--container-padding);
}

.section {
  padding: 48px 0;
}

@media (min-width: 768px) {
  .section {
    padding: 64px 0;
  }
}

@media (min-width: 1025px) {
  .section {
    padding: 96px 0;
  }
}

.section--surface {
  background-color: var(--color-surface);
  background-image: var(--grid-pattern);
  background-size: var(--grid-size) var(--grid-size);
}

.section--dark {
  background-color: var(--color-surface-dark);
  background-image: var(--gradient-dark), var(--grid-pattern);
  background-size: 100% 100%, var(--grid-size) var(--grid-size);
  color: var(--color-text-inverse);
  position: relative;
}

.section--dark::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--color-tech), transparent);
  opacity: 0.6;
}

.section--dark .section-label,
.section--dark h2,
.section--dark h3 {
  color: var(--color-text-inverse);
}

.section--dark p {
  color: var(--color-text-inverse-secondary);
}

/* Grid */
.grid {
  display: grid;
  gap: var(--space-md);
}

@media (min-width: 768px) {
  .grid {
    gap: var(--space-lg);
  }
}

.grid-2 { grid-template-columns: 1fr; }
.grid-3 { grid-template-columns: 1fr; }
.grid-4 { grid-template-columns: 1fr; }

@media (min-width: 640px) {
  .grid-2 { grid-template-columns: repeat(2, 1fr); }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
}

@media (min-width: 1025px) {
  .grid-3 { grid-template-columns: repeat(3, 1fr); }
  .grid-4 { grid-template-columns: repeat(4, 1fr); }
}

/* --------------------------------------------------------------------------
   4. Typography Components
   -------------------------------------------------------------------------- */

.section-label {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-md);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.section-label::before {
  content: "";
  display: inline-block;
  width: 24px;
  height: 1px;
  background-color: var(--color-accent);
}

h1 {
  font-size: 2.25rem;
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.02em;
}

h2 {
  font-size: 1.75rem;
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.01em;
  margin-bottom: var(--space-md);
}

h3 {
  font-size: 1.125rem;
  font-weight: 600;
  line-height: 1.3;
}

p {
  color: var(--color-text-secondary);
  line-height: 1.7;
}

@media (min-width: 1025px) {
  h1 { font-size: 3.5rem; }
  h2 { font-size: 2.5rem; }
  h3 { font-size: 1.25rem; }
}

.section-header {
  margin-bottom: var(--space-xl);
}

.section-header p {
  max-width: 600px;
  margin-top: var(--space-md);
}

/* --------------------------------------------------------------------------
   5. Navigation
   -------------------------------------------------------------------------- */

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background-color: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  z-index: 1000;
  transition: border-color var(--transition-base), box-shadow var(--transition-base);
}

.nav.scrolled {
  border-bottom-color: var(--color-border);
  box-shadow: 0 1px 0 rgba(0, 212, 255, 0.1), 0 4px 20px rgba(0, 0, 0, 0.06);
}

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

.nav-logo {
  font-size: 1.125rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--color-text);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  flex-shrink: 0;
}

.nav-logo .logo-mark {
  width: 32px;
  height: 32px;
  background: var(--gradient-button-tech);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-inverse);
  font-size: 0.875rem;
  font-weight: 700;
  position: relative;
  overflow: hidden;
}

.nav-logo .logo-mark::after {
  content: "";
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: linear-gradient(45deg, transparent 30%, rgba(255,255,255,0.3) 50%, transparent 70%);
  animation: logoShine 3s ease-in-out infinite;
}

@keyframes logoShine {
  0%, 100% { transform: translate(-100%, -100%); }
  50% { transform: translate(0%, 0%); }
}

.nav-logo .logo-text {
  font-size: 1rem;
}

/* Desktop Menu */
.nav-menu {
  display: none;
  align-items: center;
  gap: var(--space-lg);
}

.nav-item {
  position: relative;
}

.nav-link {
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--color-text);
  padding: 8px 0;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  cursor: pointer;
  position: relative;
  transition: color var(--transition-fast);
}

.nav-link::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--gradient-accent);
  transition: width var(--transition-tech);
}

.nav-link:hover::after,
.nav-link.active::after {
  width: 100%;
}

.nav-link:hover {
  color: var(--color-tech);
}

.nav-link.active {
  color: var(--color-tech);
}

.nav-link .arrow {
  font-size: 0.625rem;
  transition: transform var(--transition-fast);
}

.nav-item:hover .arrow {
  transform: rotate(180deg);
}

/* Dropdown */
.nav-dropdown {
  position: absolute;
  top: calc(100% + 8px);
  left: -16px;
  min-width: 260px;
  background-color: rgba(255, 255, 255, 0.98);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--color-border);
  border-top: 2px solid var(--color-tech);
  padding: var(--space-sm) 0;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-8px);
  transition: opacity var(--transition-base), transform var(--transition-base), visibility var(--transition-base);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.1), 0 0 0 1px rgba(0, 212, 255, 0.05);
}

.nav-dropdown::before {
  content: "";
  position: absolute;
  top: -2px;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--color-tech), var(--color-tech-blue), transparent);
}

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

.nav-dropdown a {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 10px var(--space-md);
  font-size: 0.875rem;
  color: var(--color-text);
  transition: all var(--transition-fast);
  border-left: 2px solid transparent;
}

.nav-dropdown a:hover {
  background-color: var(--color-tech-light);
  color: var(--color-tech);
  border-left-color: var(--color-tech);
  padding-left: calc(var(--space-md) + 4px);
}

.nav-dropdown .dropdown-label {
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-text-secondary);
  padding: var(--space-sm) var(--space-md) var(--space-xs);
}

/* Language Switch */
.nav-lang {
  display: none;
  align-items: center;
  gap: var(--space-sm);
  font-size: 0.8125rem;
  font-weight: 600;
  flex-shrink: 0;
}

.nav-lang a {
  color: var(--color-text-secondary);
  letter-spacing: 0.05em;
}

.nav-lang a.active {
  color: var(--color-text);
  font-weight: 700;
}

.nav-lang .divider {
  width: 1px;
  height: 14px;
  background-color: var(--color-border);
}

/* Mobile Menu Toggle */
.nav-toggle {
  display: flex;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.nav-toggle span {
  width: 24px;
  height: 2px;
  background-color: var(--color-text);
  transition: all var(--transition-fast);
}

.nav-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.nav-toggle.active span:nth-child(2) {
  opacity: 0;
}

.nav-toggle.active span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* Mobile Menu Panel */
.nav-mobile {
  display: none;
  position: fixed;
  top: var(--nav-height);
  left: 0;
  right: 0;
  bottom: 0;
  background-color: var(--color-bg);
  z-index: 999;
  overflow-y: auto;
  padding: var(--space-lg) var(--container-padding);
}

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

.nav-mobile .mobile-item {
  border-bottom: 1px solid var(--color-border);
}

.nav-mobile .mobile-link {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--space-md) 0;
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-text);
  cursor: pointer;
}

.nav-mobile .mobile-link:hover {
  color: var(--color-accent);
}

.nav-mobile .mobile-sub {
  display: none;
  padding-bottom: var(--space-md);
}

.nav-mobile .mobile-sub.active {
  display: block;
}

.nav-mobile .mobile-sub a {
  display: block;
  padding: var(--space-sm) var(--space-md);
  font-size: 0.875rem;
  color: var(--color-text-secondary);
}

.nav-mobile .mobile-sub a:hover {
  color: var(--color-accent);
}

.nav-mobile .mobile-lang {
  display: flex;
  gap: var(--space-md);
  margin-top: var(--space-lg);
  font-size: 0.875rem;
  font-weight: 600;
}

@media (min-width: 1025px) {
  .nav-menu { display: flex; }
  .nav-lang { display: flex; }
  .nav-toggle { display: none; }
  .nav-mobile { display: none !important; }
}

/* --------------------------------------------------------------------------
   6. Buttons
   -------------------------------------------------------------------------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  padding: 14px 32px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: all var(--transition-tech);
  white-space: nowrap;
  position: relative;
  overflow: hidden;
}

.btn-primary {
  background-color: var(--color-text);
  color: var(--color-text-inverse);
  border-color: var(--color-text);
}

.btn-primary:hover {
  background: var(--gradient-button-tech);
  border-color: var(--color-tech);
  color: var(--color-text-inverse);
  box-shadow: var(--shadow-tech);
}

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

.btn-secondary:hover {
  background-color: var(--color-text);
  color: var(--color-text-inverse);
  box-shadow: var(--shadow-tech);
}

.btn-ghost {
  background-color: transparent;
  color: var(--color-text);
  border: none;
  padding: 8px 0;
}

.btn-ghost::after {
  content: " \2192";
  transition: transform var(--transition-fast);
  display: inline-block;
}

.btn-ghost:hover {
  color: var(--color-tech);
}

.btn-ghost:hover::after {
  transform: translateX(4px);
}

/* Dark section button variants */
.section--dark .btn-primary {
  background: var(--gradient-button-tech);
  border-color: var(--color-tech);
}

.section--dark .btn-primary:hover {
  background: var(--color-tech);
  box-shadow: var(--shadow-tech-strong);
}

.section--dark .btn-secondary {
  color: var(--color-text-inverse);
  border-color: rgba(255, 255, 255, 0.3);
}

.section--dark .btn-secondary:hover {
  background-color: rgba(255, 255, 255, 0.1);
  border-color: var(--color-tech);
  color: var(--color-tech);
  box-shadow: var(--shadow-tech);
}

.section--dark .btn-ghost {
  color: var(--color-text-inverse);
}

.section--dark .btn-ghost:hover {
  color: var(--color-tech);
}

/* --------------------------------------------------------------------------
   7. Hero Section
   -------------------------------------------------------------------------- */

.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: var(--nav-height);
  overflow: hidden;
  background: var(--gradient-tech);
}

.hero::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-image: var(--grid-pattern);
  background-size: var(--grid-size) var(--grid-size);
  opacity: 0.5;
}

.hero::after {
  content: "";
  position: absolute;
  top: 0;
  left: 50%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(0, 212, 255, 0.08) 0%, transparent 70%);
  transform: translateX(-50%);
  pointer-events: none;
}

.hero-inner {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-xl);
  width: 100%;
  position: relative;
  z-index: 1;
}

@media (min-width: 1025px) {
  .hero-inner {
    grid-template-columns: 1fr 1fr;
    align-items: center;
  }
}

.hero-content {
  max-width: 600px;
}

.hero-label {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-tech);
  margin-bottom: var(--space-md);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.hero-label::before {
  content: "";
  width: 32px;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--color-tech));
}

.hero-title {
  font-size: 2.5rem;
  font-weight: 700;
  line-height: 1.05;
  letter-spacing: -0.02em;
  margin-bottom: var(--space-md);
  color: #ffffff;
}

@media (min-width: 1025px) {
  .hero-title {
    font-size: 4rem;
  }
}

.hero-subtitle {
  font-size: 1.0625rem;
  color: var(--color-text-inverse-secondary);
  line-height: 1.7;
  margin-bottom: var(--space-lg);
  max-width: 480px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
}

.hero-visual {
  position: relative;
  aspect-ratio: 4 / 3;
  background-color: rgba(255, 255, 255, 0.03);
  border: 1px solid rgba(0, 212, 255, 0.2);
  overflow: hidden;
}

.hero-visual::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(135deg, rgba(0, 212, 255, 0.05) 0%, transparent 50%, rgba(10, 132, 255, 0.05) 100%);
  pointer-events: none;
}

/* Scanning line animation */
.hero-visual::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--color-tech), transparent);
  animation: scanLine 4s linear infinite;
  opacity: 0.5;
}

@keyframes scanLine {
  0% { top: 0; }
  100% { top: 100%; }
}

.hero-visual-placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  height: 100%;
  color: var(--color-text-inverse-secondary);
  font-size: 0.875rem;
  text-align: center;
  padding: var(--space-lg);
  position: relative;
  z-index: 1;
}

/* --------------------------------------------------------------------------
   8. Cards
   -------------------------------------------------------------------------- */

.card {
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  padding: var(--space-lg);
  transition: border-color var(--transition-tech), transform var(--transition-tech), box-shadow var(--transition-tech);
  position: relative;
  height: 100%;
  display: flex;
  flex-direction: column;
}

.card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--color-tech), transparent);
  opacity: 0;
  transition: opacity var(--transition-tech);
}

.card:hover {
  border-color: rgba(0, 212, 255, 0.3);
  transform: translateY(-4px);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.08), 0 0 0 1px rgba(0, 212, 255, 0.1);
}

.card:hover::before {
  opacity: 1;
}

.card-icon {
  width: 56px;
  height: 56px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--space-md);
  font-size: 1.5rem;
  transition: all var(--transition-tech);
}

.card:hover .card-icon {
  border-color: var(--color-tech);
  background-color: var(--color-tech-light);
  box-shadow: var(--shadow-tech);
}

.card:hover .card-icon svg {
  stroke: var(--color-tech);
}

.card-title {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: var(--space-sm);
}

.card-text {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
  flex-grow: 1;
  margin-bottom: var(--space-md);
}

.card-link {
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--color-text);
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
}

.card:hover .card-link {
  color: var(--color-tech);
}

.card-link::after {
  content: "\2192";
  transition: transform var(--transition-fast);
}

.card:hover .card-link::after {
  transform: translateX(4px);
}

/* Numbered Card (Toolbox style) */
.card-numbered {
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  padding: var(--space-lg);
  transition: border-color var(--transition-tech), transform var(--transition-tech), box-shadow var(--transition-tech);
  position: relative;
  display: flex;
  flex-direction: column;
  height: 100%;
}

.card-numbered::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--color-tech), transparent);
  opacity: 0;
  transition: opacity var(--transition-tech);
}

.card-numbered:hover {
  border-color: rgba(0, 212, 255, 0.3);
  transform: translateY(-4px);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.08), 0 0 0 1px rgba(0, 212, 255, 0.1);
}

.card-numbered:hover::before {
  opacity: 1;
}

.card-number {
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-tech);
  line-height: 1;
  margin-bottom: var(--space-sm);
  font-family: var(--font-mono);
  text-shadow: 0 0 20px rgba(0, 212, 255, 0.2);
}

.card-category {
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-sm);
}

.card-numbered .card-title {
  margin-bottom: var(--space-sm);
}

.card-numbered .card-text {
  flex-grow: 1;
  margin-bottom: var(--space-md);
}

.card-numbered .card-link {
  margin-top: auto;
}

/* --------------------------------------------------------------------------
   9. Stats Section
   -------------------------------------------------------------------------- */

.stats {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-lg);
}

@media (min-width: 1025px) {
  .stats {
    grid-template-columns: repeat(4, 1fr);
  }
}

.stat-item {
  text-align: left;
  padding: var(--space-lg) 0;
  border-top: 1px solid var(--color-border-dark);
}

.section--dark .stat-item {
  border-top-color: var(--color-border-dark);
}

.stat-number {
  font-size: 2.5rem;
  font-weight: 700;
  line-height: 1;
  color: var(--color-tech);
  margin-bottom: var(--space-xs);
  text-shadow: 0 0 30px rgba(0, 212, 255, 0.3);
}

@media (min-width: 1025px) {
  .stat-number {
    font-size: 3rem;
  }
}

.stat-label {
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--color-text-inverse-secondary);
}

.section--surface .stat-item {
  border-top-color: var(--color-border);
}

.section--surface .stat-label {
  color: var(--color-text-secondary);
}

/* --------------------------------------------------------------------------
   10. Sectors Grid
   -------------------------------------------------------------------------- */

.sectors {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  background-color: var(--color-border);
  border: 1px solid var(--color-border);
}

@media (min-width: 768px) {
  .sectors {
    grid-template-columns: repeat(4, 1fr);
  }
}

.sector-item {
  background-color: var(--color-bg);
  padding: var(--space-lg);
  text-align: center;
  transition: background-color var(--transition-fast);
  cursor: pointer;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-sm);
}

.sector-item:hover {
  background-color: var(--color-surface);
}

.sector-icon {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  color: var(--color-text);
  transition: color var(--transition-fast);
}

.sector-item:hover .sector-icon {
  color: var(--color-accent);
}

.sector-name {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-text);
}

/* --------------------------------------------------------------------------
   11. Article / Blog Cards
   -------------------------------------------------------------------------- */

.article-card {
  display: flex;
  flex-direction: column;
  border: 1px solid var(--color-border);
  transition: border-color var(--transition-base);
  height: 100%;
}

.article-card:hover {
  border-color: var(--color-accent);
}

.article-image {
  aspect-ratio: 16 / 10;
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-secondary);
  font-size: 0.75rem;
}

.article-body {
  padding: var(--space-lg);
  display: flex;
  flex-direction: column;
  flex-grow: 1;
}

.article-meta {
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-sm);
  display: flex;
  gap: var(--space-sm);
}

.article-meta .article-type {
  color: var(--color-accent);
}

.article-title {
  font-size: 1rem;
  font-weight: 600;
  line-height: 1.4;
  margin-bottom: var(--space-md);
  flex-grow: 1;
}

.article-card:hover .article-title {
  color: var(--color-accent);
}

.article-date {
  font-size: 0.75rem;
  color: var(--color-text-secondary);
}

/* --------------------------------------------------------------------------
   12. CTA Section
   -------------------------------------------------------------------------- */

.cta {
  background: var(--gradient-tech);
  color: var(--color-text-inverse);
  padding: 80px 0;
  position: relative;
  overflow: hidden;
}

.cta::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-image: var(--grid-pattern);
  background-size: var(--grid-size) var(--grid-size);
  opacity: 0.3;
}

.cta::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--color-tech), transparent);
}

@media (min-width: 1025px) {
  .cta {
    padding: 120px 0;
  }
}

.cta-inner {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-xl);
  align-items: center;
}

@media (min-width: 768px) {
  .cta-inner {
    grid-template-columns: 2fr 1fr;
  }
}

.cta-title {
  font-size: 2rem;
  font-weight: 700;
  line-height: 1.2;
  color: var(--color-text-inverse);
  margin-bottom: var(--space-md);
}

@media (min-width: 1025px) {
  .cta-title {
    font-size: 3rem;
  }
}

.cta-text {
  color: var(--color-text-inverse-secondary);
  font-size: 1rem;
  max-width: 480px;
}

.cta-actions {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.cta-phone {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-tech);
  letter-spacing: -0.01em;
}

/* --------------------------------------------------------------------------
   13. Footer
   -------------------------------------------------------------------------- */

.footer {
  background-color: var(--color-surface-dark);
  background-image: var(--gradient-dark);
  color: var(--color-text-inverse-secondary);
  padding: var(--space-2xl) 0 var(--space-lg);
  border-top: 1px solid var(--color-border-dark);
  position: relative;
}

.footer::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--color-tech), transparent);
  opacity: 0.4;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-xl);
  margin-bottom: var(--space-xl);
}

@media (min-width: 768px) {
  .footer-grid {
    grid-template-columns: 2fr 1fr 1fr 1fr;
  }
}

.footer-brand .footer-logo {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--color-text-inverse);
  margin-bottom: var(--space-md);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.footer-brand p {
  color: var(--color-text-inverse-secondary);
  font-size: 0.875rem;
  max-width: 320px;
}

.footer-col h4 {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-text-inverse);
  margin-bottom: var(--space-md);
}

.footer-col ul li {
  margin-bottom: var(--space-sm);
}

.footer-col ul li a {
  color: var(--color-text-inverse-secondary);
  font-size: 0.875rem;
  transition: color var(--transition-fast);
}

.footer-col ul li a:hover {
  color: var(--color-accent);
}

.footer-bottom {
  padding-top: var(--space-lg);
  border-top: 1px solid var(--color-border-dark);
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-md);
}

.footer-copy {
  font-size: 0.75rem;
  color: var(--color-text-inverse-secondary);
}

.footer-social {
  display: flex;
  gap: var(--space-md);
}

.footer-social a {
  font-size: 0.75rem;
  color: var(--color-text-inverse-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.footer-social a:hover {
  color: var(--color-tech);
}

/* --------------------------------------------------------------------------
   14. Page Header (Sub Pages)
   -------------------------------------------------------------------------- */

.page-header {
  padding-top: calc(var(--nav-height) + var(--space-2xl));
  padding-bottom: var(--space-xl);
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
}

.page-header .section-label {
  margin-bottom: var(--space-md);
}

.page-header h1 {
  font-size: 2rem;
  margin-bottom: var(--space-md);
}

@media (min-width: 1025px) {
  .page-header h1 {
    font-size: 3rem;
  }
}

.page-header p {
  max-width: 600px;
}

/* --------------------------------------------------------------------------
   15. Animations (Scroll Reveal)
   -------------------------------------------------------------------------- */

.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }
.reveal-delay-4 { transition-delay: 0.4s; }

/* --------------------------------------------------------------------------
   16. Toolbox Category Filter
   -------------------------------------------------------------------------- */

.toolbox-filter {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-bottom: var(--space-xl);
}

.filter-btn {
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  padding: 10px 20px;
  border: 1px solid var(--color-border);
  background-color: var(--color-bg);
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: all var(--transition-tech);
}

.filter-btn:hover {
  border-color: var(--color-tech);
  color: var(--color-tech);
  box-shadow: var(--shadow-tech);
}

.filter-btn.active {
  background: var(--gradient-button-tech);
  border-color: var(--color-tech);
  color: var(--color-text-inverse);
  box-shadow: var(--shadow-tech);
}

/* --------------------------------------------------------------------------
   17. Brand Logo Carousel
   -------------------------------------------------------------------------- */

.brand-carousel {
  position: relative;
  overflow: hidden;
  padding: var(--space-lg) 0;
}

.brand-carousel-track {
  display: flex;
  gap: var(--space-xl);
  /* 每组 10 个 Logo；时长按数量等比缩短，保持与原先 14 个时相同的滚动速度 */
  animation: brandScroll 21s linear infinite;
  width: max-content;
}

.brand-carousel:hover .brand-carousel-track {
  animation-play-state: paused;
}

@keyframes brandScroll {
  0% { transform: translateX(0); }
  100% { transform: translateX(-50%); }
}

.brand-logo-item {
  flex-shrink: 0;
  width: 160px;
  height: 80px;
  display: flex;
  align-items: center;
  justify-content: center;
  /* 品牌 Logo 自带统一底色 #193134，卡片用同色，拼成一整条品牌墙 */
  border: 1px solid #193134;
  background-color: #193134;
  padding: 12px;
  transition: all var(--transition-tech);
  position: relative;
  overflow: hidden;
}

.brand-logo-item::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--color-tech), transparent);
  opacity: 0;
  transition: opacity var(--transition-tech);
}

.brand-logo-item:hover {
  border-color: var(--color-tech);
  box-shadow: var(--shadow-tech);
  transform: translateY(-2px);
}

.brand-logo-item:hover::before {
  opacity: 1;
}

.brand-logo-text {
  font-size: 0.875rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--color-text-secondary);
  text-align: center;
  transition: color var(--transition-fast);
}

.brand-logo-item:hover .brand-logo-text {
  color: var(--color-tech);
}

/* Gradient mask edges for carousel */
.brand-carousel::before,
.brand-carousel::after {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  width: 80px;
  z-index: 2;
  pointer-events: none;
}

.brand-carousel::before {
  left: 0;
  background: linear-gradient(90deg, var(--color-bg), transparent);
}

.brand-carousel::after {
  right: 0;
  background: linear-gradient(270deg, var(--color-bg), transparent);
}

/* Dark section variant */
.section--dark .brand-logo-item {
  background-color: rgba(255, 255, 255, 0.03);
  border-color: rgba(255, 255, 255, 0.1);
}

.section--dark .brand-logo-text {
  color: var(--color-text-inverse-secondary);
}

.section--dark .brand-carousel::before {
  background: linear-gradient(90deg, var(--color-surface-dark), transparent);
}

.section--dark .brand-carousel::after {
  background: linear-gradient(270deg, var(--color-surface-dark), transparent);
}

/* --------------------------------------------------------------------------
   18. Tech Decorative Elements
   -------------------------------------------------------------------------- */

.tech-line {
  position: relative;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--color-border), transparent);
  margin: var(--space-xl) 0;
}

.tech-line::after {
  content: "";
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 120px;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--color-tech), transparent);
}

.tech-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 12px;
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  background-color: var(--color-tech-light);
  color: var(--color-tech);
  border: 1px solid rgba(0, 212, 255, 0.2);
}

.tech-badge::before {
  content: "";
  width: 6px;
  height: 6px;
  background: var(--color-tech);
  border-radius: 50%;
  animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(1.2); }
}

/* Corner accent for cards */
.card-tech-corners {
  position: relative;
}

.card-tech-corners::before,
.card-tech-corners::after {
  content: "";
  position: absolute;
  width: 12px;
  height: 12px;
  border: 1px solid var(--color-tech);
  opacity: 0;
  transition: opacity var(--transition-tech);
}

.card-tech-corners::before {
  top: -1px;
  left: -1px;
  border-right: none;
  border-bottom: none;
}

.card-tech-corners::after {
  bottom: -1px;
  right: -1px;
  border-left: none;
  border-top: none;
}

.card-tech-corners:hover::before,
.card-tech-corners:hover::after {
  opacity: 1;
}

/* --------------------------------------------------------------------------
   17. Placeholder Styles
   -------------------------------------------------------------------------- */

.placeholder-box {
  background-color: var(--color-surface);
  border: 1px dashed var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-secondary);
  font-size: 0.8125rem;
  text-align: center;
  padding: var(--space-lg);
}

.placeholder-box svg {
  width: 48px;
  height: 48px;
  margin-bottom: var(--space-sm);
  opacity: 0.3;
}

/* --------------------------------------------------------------------------
   18. Utility Classes
   -------------------------------------------------------------------------- */

.text-center { text-align: center; }
.text-accent { color: var(--color-accent); }
.mt-sm { margin-top: var(--space-sm); }
.mt-md { margin-top: var(--space-md); }
.mt-lg { margin-top: var(--space-lg); }
.mt-xl { margin-top: var(--space-xl); }
.mb-sm { margin-bottom: var(--space-sm); }
.mb-md { margin-bottom: var(--space-md); }
.mb-lg { margin-bottom: var(--space-lg); }
.mb-xl { margin-bottom: var(--space-xl); }

.hidden { display: none !important; }

/* --------------------------------------------------------------------------
   19. Image Asset Support
   素材到位后，只需把占位 <span> 换成 <img>，无需改动此处样式。
   所有图片位均为等比裁切 / 等比缩放，不会出现拉伸变形。
   -------------------------------------------------------------------------- */

/* Hero 主视觉 — 4:3 等比裁切 */
.hero-visual > img,
.hero-visual > video.hero-media {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  display: block;
  z-index: 0;
}

/* 案例 / 文章卡片 — 16:10 等比裁切 + hover 轻微放大 */
.article-image {
  position: relative;
  overflow: hidden;
}

.article-image img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  display: block;
  transition: transform var(--transition-slow);
}

.article-card:hover .article-image img {
  transform: scale(1.04);
}

/* 核心能力卡片配图（可选，用于替换内联 SVG 图标） */
.card-photo {
  aspect-ratio: 16 / 10;
  overflow: hidden;
  margin: calc(var(--space-lg) * -1) calc(var(--space-lg) * -1) var(--space-md);
  background-color: var(--color-surface);
}

.card-photo img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

/* 品牌 Logo — 等比缩放、不裁切、透明底；默认灰度，hover 恢复彩色 */
/* 品牌 Logo 本身已是统一深青绿底 + 白字，不做灰度化，保留品牌色 */
.brand-logo-item img {
  max-width: 100%;
  max-height: 100%;
  width: auto;
  height: auto;
  object-fit: contain;
  display: block;
  filter: none;
  opacity: 0.92;
  transition: filter var(--transition-tech), opacity var(--transition-tech);
}

.brand-logo-item:hover img {
  filter: none;
  opacity: 1;
}

.section--dark .brand-logo-item img {
  filter: grayscale(1) brightness(0) invert(1);
  opacity: 0.8;
}

.section--dark .brand-logo-item:hover img {
  filter: none;
  opacity: 1;
}

/* 导航 / 页脚 Logo */
.nav-logo img,
.footer-logo img {
  height: 32px;
  width: auto;
  max-width: 180px;
  object-fit: contain;
  display: block;
}

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

/* 白底 PNG 的品牌 Logo：用正片叠底把白底融入浅色卡片，无需去背。
   仅适用于浅色背景区块（品牌轮播区）；深色区块不要用这个 class。
   素材若是没有透明通道的 JPG/白底 PNG，在 .brand-logo-item 上加
   class="brand-logo-item brand-logo-item--white-bg" 即可。 */
.brand-logo-item--white-bg {
  background-color: #ffffff;
}

.brand-logo-item--white-bg img {
  mix-blend-mode: multiply;
  filter: grayscale(1) contrast(1.05);
  opacity: 0.9;
}

.brand-logo-item--white-bg:hover img {
  filter: none;
  opacity: 1;
}

/* --------------------------------------------------------------------------
   20. Print
   -------------------------------------------------------------------------- */

@media print {
  .nav, .nav-mobile, .nav-toggle, .cta-actions { display: none !important; }
  .hero { min-height: auto; }
}