/* ===== YUNMENG Enterprise Site - NVIDIA-inspired AI Infrastructure Style ===== */

:root {
  --bg-primary: #0a0a0a;
  --bg-secondary: #111111;
  --bg-tertiary: #1a1a1a;
  --bg-card: #141414;
  --bg-card-hover: #1c1c1c;
  --green-accent: #76b900;
  --green-glow: rgba(118, 185, 0, 0.15);
  --green-dim: #5a8f00;
  --green-light: #8ed100;
  --text-primary: #f0f0f0;
  --text-secondary: #a0a0a0;
  --text-tertiary: #666666;
  --border-subtle: rgba(255, 255, 255, 0.06);
  --border-green: rgba(118, 185, 0, 0.25);
  --font-stack: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --max-width: 1280px;
  --nav-height: 64px;
  --section-gap: 120px;
  --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-smooth: 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

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

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

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

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

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

/* ===== NAVIGATION ===== */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  z-index: 1000;
  background: rgba(10, 10, 10, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-subtle);
  transition: background var(--transition-fast);
}

.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 32px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 18px;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.nav-logo img {
  height: 32px;
  width: auto;
}

.nav-logo-text {
  color: var(--text-primary);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 36px;
  list-style: none;
}

.nav-links a {
  font-size: 14px;
  font-weight: 500;
  color: var(--text-secondary);
  transition: color var(--transition-fast);
  position: relative;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--text-primary);
}

.nav-links a.active::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--green-accent);
  border-radius: 1px;
}

.nav-cta {
  font-size: 13px;
  font-weight: 600;
  padding: 8px 20px;
  background: var(--green-accent);
  color: #000;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.nav-cta:hover {
  background: var(--green-light);
  transform: translateY(-1px);
}

.nav-mobile-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.nav-mobile-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-primary);
  transition: all var(--transition-fast);
  border-radius: 1px;
}

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

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

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

/* ===== HERO ===== */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  position: relative;
  overflow: hidden;
  padding-top: var(--nav-height);
}

.hero-bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 60% at 50% 40%, rgba(118, 185, 0, 0.08) 0%, transparent 70%),
    radial-gradient(ellipse 50% 80% at 80% 20%, rgba(118, 185, 0, 0.04) 0%, transparent 60%),
    var(--bg-primary);
}

.hero-grid-overlay {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(118, 185, 0, 0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(118, 185, 0, 0.03) 1px, transparent 1px);
  background-size: 60px 60px;
  mask-image: radial-gradient(ellipse 70% 50% at 50% 50%, black 20%, transparent 70%);
  -webkit-mask-image: radial-gradient(ellipse 70% 50% at 50% 50%, black 20%, transparent 70%);
}

.hero-content {
  position: relative;
  z-index: 2;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 80px 32px;
  width: 100%;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  background: var(--green-glow);
  border: 1px solid var(--border-green);
  border-radius: 100px;
  font-size: 13px;
  font-weight: 500;
  color: var(--green-accent);
  margin-bottom: 32px;
}

.hero-badge-dot {
  width: 6px;
  height: 6px;
  background: var(--green-accent);
  border-radius: 50%;
  animation: pulse-dot 2s ease-in-out infinite;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.4; }
}

.hero-title {
  font-size: clamp(36px, 5.5vw, 72px);
  font-weight: 800;
  line-height: 1.08;
  letter-spacing: -0.03em;
  margin-bottom: 24px;
  max-width: 900px;
}

.hero-title .accent {
  color: var(--green-accent);
}

.hero-subtitle {
  font-size: clamp(16px, 1.8vw, 20px);
  color: var(--text-secondary);
  max-width: 680px;
  line-height: 1.65;
  margin-bottom: 48px;
}

.hero-actions {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 32px;
  background: var(--green-accent);
  color: #000;
  font-size: 15px;
  font-weight: 600;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.btn-primary:hover {
  background: var(--green-light);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(118, 185, 0, 0.25);
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 32px;
  background: transparent;
  color: var(--text-primary);
  font-size: 15px;
  font-weight: 600;
  border: 1px solid var(--border-subtle);
  border-radius: 6px;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.btn-secondary:hover {
  border-color: var(--text-tertiary);
  background: rgba(255, 255, 255, 0.03);
}

/* ===== STATS BAR ===== */
.stats-bar {
  border-top: 1px solid var(--border-subtle);
  border-bottom: 1px solid var(--border-subtle);
  background: var(--bg-secondary);
}

.stats-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 48px 32px;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 32px;
}

.stat-item {
  text-align: center;
}

.stat-number {
  font-size: clamp(32px, 4vw, 48px);
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--green-accent);
  line-height: 1;
  margin-bottom: 8px;
}

.stat-label {
  font-size: 14px;
  color: var(--text-secondary);
  font-weight: 400;
}

/* ===== SECTIONS ===== */
.section {
  padding: var(--section-gap) 0;
  position: relative;
}

.section-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 32px;
}

.section-header {
  margin-bottom: 64px;
}

.section-label {
  display: inline-block;
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--green-accent);
  margin-bottom: 16px;
}

.section-title {
  font-size: clamp(28px, 3.5vw, 48px);
  font-weight: 800;
  letter-spacing: -0.025em;
  line-height: 1.15;
  max-width: 700px;
}

.section-subtitle {
  font-size: 17px;
  color: var(--text-secondary);
  margin-top: 16px;
  max-width: 600px;
  line-height: 1.6;
}

/* ===== ABOUT SECTION ===== */
.about-section {
  background: var(--bg-secondary);
}

.about-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.about-card {
  padding: 32px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  transition: all var(--transition-smooth);
}

.about-card:hover {
  border-color: var(--border-green);
  background: var(--bg-card-hover);
  transform: translateY(-4px);
}

.about-card-icon {
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--green-glow);
  border: 1px solid var(--border-green);
  border-radius: 8px;
  margin-bottom: 20px;
  font-size: 18px;
}

.about-card h3 {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 12px;
  letter-spacing: -0.01em;
}

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

/* ===== FEATURES SECTION ===== */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.feature-card {
  padding: 36px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  transition: all var(--transition-smooth);
  position: relative;
  overflow: hidden;
}

.feature-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--green-accent), transparent);
  opacity: 0;
  transition: opacity var(--transition-smooth);
}

.feature-card:hover {
  border-color: var(--border-green);
  transform: translateY(-4px);
}

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

.feature-icon {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--green-glow);
  border-radius: 10px;
  margin-bottom: 24px;
  font-size: 22px;
}

.feature-card h3 {
  font-size: 19px;
  font-weight: 700;
  margin-bottom: 12px;
  letter-spacing: -0.01em;
}

.feature-card p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ===== PRODUCTS SECTION ===== */
.products-section {
  background: var(--bg-secondary);
}

.products-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
}

.product-card {
  padding: 48px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: 12px;
  transition: all var(--transition-smooth);
  position: relative;
  overflow: hidden;
}

.product-card:hover {
  border-color: var(--border-green);
}

.product-card-tag {
  display: inline-block;
  padding: 4px 12px;
  background: var(--green-glow);
  color: var(--green-accent);
  font-size: 12px;
  font-weight: 600;
  border-radius: 4px;
  margin-bottom: 20px;
}

.product-card h3 {
  font-size: 24px;
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 12px;
}

.product-card p {
  font-size: 15px;
  color: var(--text-secondary);
  line-height: 1.65;
  margin-bottom: 28px;
}

.product-features {
  list-style: none;
  margin-bottom: 32px;
}

.product-features li {
  font-size: 14px;
  color: var(--text-secondary);
  padding: 8px 0;
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  gap: 10px;
}

.product-features li:last-child {
  border-bottom: none;
}

.product-features li::before {
  content: '';
  width: 6px;
  height: 6px;
  background: var(--green-accent);
  border-radius: 50%;
  flex-shrink: 0;
}

.product-actions {
  display: flex;
  gap: 12px;
}

/* ===== PARTNERS SECTION ===== */
.partners-logos {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 64px;
  flex-wrap: wrap;
  margin-bottom: 48px;
}

.partner-logo {
  height: 48px;
  width: auto;
  opacity: 0.6;
  transition: opacity var(--transition-fast);
  filter: brightness(0) invert(1);
}

.partner-logo:hover {
  opacity: 1;
}

.partners-text {
  max-width: 800px;
  margin: 0 auto;
  text-align: center;
}

.partners-text p {
  font-size: 15px;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ===== CTA SECTION ===== */
.cta-section {
  background: var(--bg-secondary);
  text-align: center;
}

.cta-title {
  font-size: clamp(28px, 3.5vw, 44px);
  font-weight: 800;
  letter-spacing: -0.025em;
  margin-bottom: 16px;
}

.cta-subtitle {
  font-size: 17px;
  color: var(--text-secondary);
  margin-bottom: 40px;
  max-width: 560px;
  margin-left: auto;
  margin-right: auto;
}

/* ===== FOOTER ===== */
.footer {
  border-top: 1px solid var(--border-subtle);
  padding: 64px 0 40px;
  background: var(--bg-primary);
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 32px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 48px;
}

.footer-brand p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.65;
  margin-top: 16px;
  max-width: 320px;
}

.footer-col h4 {
  font-size: 13px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-tertiary);
  margin-bottom: 20px;
}

.footer-col ul {
  list-style: none;
}

.footer-col ul li {
  margin-bottom: 12px;
}

.footer-col ul li a {
  font-size: 14px;
  color: var(--text-secondary);
  transition: color var(--transition-fast);
}

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

.footer-bottom {
  padding-top: 32px;
  border-top: 1px solid var(--border-subtle);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 13px;
  color: var(--text-tertiary);
}

/* ===== MOBILE MENU ===== */
.mobile-menu {
  display: none;
  position: fixed;
  top: var(--nav-height);
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(10, 10, 10, 0.98);
  backdrop-filter: blur(20px);
  z-index: 999;
  padding: 32px;
  flex-direction: column;
  gap: 0;
}

.mobile-menu.open {
  display: flex;
}

.mobile-menu a {
  display: block;
  padding: 16px 0;
  font-size: 18px;
  font-weight: 500;
  color: var(--text-secondary);
  border-bottom: 1px solid var(--border-subtle);
  transition: color var(--transition-fast);
}

.mobile-menu a:hover {
  color: var(--text-primary);
}

/* ===== RESPONSIVE ===== */
@media (max-width: 1024px) {
  :root {
    --section-gap: 80px;
  }

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

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

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

@media (max-width: 768px) {
  :root {
    --section-gap: 64px;
    --nav-height: 56px;
  }

  .nav-links,
  .nav-cta {
    display: none;
  }

  .nav-mobile-toggle {
    display: flex;
  }

  .hero-content {
    padding: 60px 20px;
  }

  .hero-title {
    font-size: clamp(28px, 8vw, 40px);
  }

  .hero-subtitle {
    font-size: 15px;
  }

  .hero-actions {
    flex-direction: column;
  }

  .btn-primary,
  .btn-secondary {
    width: 100%;
    justify-content: center;
  }

  .stats-inner {
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
    padding: 32px 20px;
  }

  .section-inner {
    padding: 0 20px;
  }

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

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

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

  .product-card {
    padding: 32px;
  }

  .partners-logos {
    gap: 32px;
  }

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

  .footer-bottom {
    flex-direction: column;
    gap: 12px;
    text-align: center;
  }
}

@media (max-width: 480px) {
  .stats-inner {
    grid-template-columns: 1fr;
  }

  .stat-item {
    text-align: left;
    padding: 16px 0;
    border-bottom: 1px solid var(--border-subtle);
  }

  .stat-item:last-child {
    border-bottom: none;
  }
}

/* ===== ANIMATIONS ===== */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

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