/* ========================================
   航链科技 Navlyn — Design System & Styles
   ======================================== */

/* --- CSS Custom Properties --- */
:root {
  --bg-primary: #000000;
  --bg-secondary: #0a0a0a;
  --bg-card: #0d0d0d;
  --text-primary: #f1f0ea;
  --text-secondary: #8a8a8a;
  --accent: #2D27E3;
  --accent-hover: #4a45f0;
  --border: #1a1a1a;
  --border-light: #2a2a2a;

  --font-stack: 'Helvetica Neue', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-mono: 'SF Mono', 'Fira Code', monospace;

  --ease-expo: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-out: cubic-bezier(0.33, 1, 0.68, 1);

  --duration-enter: 1200ms;
  --duration-interact: 400ms;

  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 1rem;
  --space-4: 1.5rem;
  --space-5: 2rem;
  --space-6: 4rem;
  --space-7: 6rem;
  --space-8: 8rem;

  --nav-height: 80px;
  --container-max: 1280px;
  --container-wide: 1440px;
}

/* --- Reset --- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font-stack);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; height: auto; display: block; }
button { font: inherit; cursor: pointer; border: none; background: none; color: inherit; }
ul { list-style: none; }

/* --- Utility --- */
.container { max-width: var(--container-max); margin: 0 auto; padding: 0 var(--space-4); }
.section { padding: var(--space-8) 0; }

/* --- Section Headers --- */
.section-header { text-align: center; margin-bottom: var(--space-7); }
.section-tag {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: var(--space-3);
}
.section-title {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 700;
  letter-spacing: -0.04em;
  line-height: 1.1;
  margin-bottom: var(--space-3);
}
.section-desc {
  font-size: 1.125rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto;
}

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.875rem 2rem;
  font-size: 0.9375rem;
  font-weight: 600;
  border-radius: 4px;
  transition: all var(--duration-interact) var(--ease-out);
  white-space: nowrap;
}
.btn-primary {
  background: var(--accent);
  color: #fff;
}
.btn-primary:hover {
  background: var(--accent-hover);
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(45, 39, 227, 0.3);
}
.btn-outline {
  border: 1px solid var(--text-secondary);
  color: var(--text-primary);
  background: transparent;
}
.btn-outline:hover {
  border-color: var(--accent);
  color: var(--accent);
  transform: translateY(-2px);
}
.btn-sm { padding: 0.625rem 1.25rem; font-size: 0.875rem; }

/* ========================================
   1. NAVBAR
   ======================================== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--nav-height);
  transition: background var(--duration-interact) var(--ease-out),
              box-shadow var(--duration-interact) var(--ease-out);
}
.navbar.scrolled {
  background: rgba(0, 0, 0, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  box-shadow: 0 1px 0 var(--border);
}
.nav-inner {
  max-width: var(--container-wide);
  margin: 0 auto;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--space-4);
}
.nav-logo {
  display: flex;
  align-items: center;
  flex-shrink: 0;
}
.nav-logo-img {
  height: 180px;
  width: auto;
}
.nav-links {
  display: flex;
  gap: var(--space-4);
}
.nav-link {
  font-size: 1rem;
  color: var(--text-secondary);
  transition: color var(--duration-interact) var(--ease-out);
  position: relative;
  padding: 0.25rem 0;
}
.nav-link::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 1px;
  background: var(--accent);
  transition: width var(--duration-interact) var(--ease-out);
}
.nav-link:hover, .nav-link.active { color: var(--text-primary); }
.nav-link:hover::after, .nav-link.active::after { width: 100%; }
.nav-cta {
  font-size: 0.9375rem;
  font-weight: 600;
  padding: 0.5rem 1.25rem;
  border: 1px solid var(--border-light);
  border-radius: 4px;
  color: var(--text-primary);
  transition: all var(--duration-interact) var(--ease-out);
}
.nav-cta:hover {
  border-color: var(--accent);
  color: var(--accent);
}
.lang-toggle {
  font-size: 0.8125rem;
  font-weight: 600;
  padding: 0.3rem 0.75rem;
  border: 1px solid var(--border-light);
  border-radius: 4px;
  color: var(--text-primary);
  transition: all var(--duration-interact) var(--ease-out);
  margin-left: 0.75rem;
  letter-spacing: 0.05em;
  flex-shrink: 0;
}
.lang-toggle:hover {
  border-color: var(--accent);
  color: var(--accent);
}
.mobile-lang-toggle {
  margin: var(--space-5) auto 0;
  font-size: 1rem;
  padding: 0.5rem 1.5rem;
}
.nav-hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 4px;
  z-index: 1001;
}
.nav-hamburger span {
  display: block;
  width: 24px;
  height: 1.5px;
  background: var(--text-primary);
  transition: all 0.3s var(--ease-out);
}
.nav-hamburger.active span:nth-child(1) { transform: rotate(45deg) translate(5px, 4px); }
.nav-hamburger.active span:nth-child(2) { opacity: 0; }
.nav-hamburger.active span:nth-child(3) { transform: rotate(-45deg) translate(5px, -4px); }

/* Mobile Menu */
.mobile-menu {
  position: fixed;
  inset: 0;
  z-index: 999;
  background: rgba(0, 0, 0, 0.95);
  backdrop-filter: blur(20px);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.4s var(--ease-out);
}
.mobile-menu.active { opacity: 1; pointer-events: all; }
.mobile-menu-links {
  text-align: center;
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}
.mobile-menu-links a {
  font-size: 2rem;
  font-weight: 700;
  color: var(--text-primary);
  transition: color 0.3s;
}
.mobile-menu-links a:hover { color: var(--accent); }
.mobile-cta { color: var(--accent) !important; }

/* ========================================
   2. HERO
   ======================================== */
.hero {
  position: relative;
  width: 100%;
  height: 100vh;
  min-height: 600px;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}
.hero-video {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.hero-scroll-indicator {
  position: absolute;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  z-index: 1;
  color: var(--text-secondary);
  animation: bounce 2s infinite;
}
@keyframes bounce {
  0%, 20%, 50%, 80%, 100% { transform: translateX(-50%) translateY(0); }
  40% { transform: translateX(-50%) translateY(-10px); }
  60% { transform: translateX(-50%) translateY(-5px); }
}

/* ========================================
   3. PRODUCTS GRID
   ======================================== */
.product-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-4);
}
.product-card {
  position: relative;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  transition: all var(--duration-interact) var(--ease-out);
  display: block;
}
.product-card:hover {
  transform: translateY(-8px);
  border-color: var(--accent);
}
.product-card-image {
  height: 240px;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-4);
  overflow: hidden;
  background: var(--bg-card);
}
.product-card-image img {
  max-height: 100%;
  width: auto;
  object-fit: contain;
  mix-blend-mode: screen;
}
.product-card-placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
}
.product-card-placeholder svg {
  width: 160px;
  height: 128px;
}
.product-card-body { padding: var(--space-4); }
.product-card-tag {
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.5rem;
  display: block;
}
.product-card-title {
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 0.5rem;
}
.product-card-desc {
  font-size: 0.875rem;
  color: var(--text-secondary);
}
.product-card-glow {
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 80%;
  height: 120px;
  background: radial-gradient(ellipse, rgba(45,39,227,0.12), transparent 70%);
  opacity: 0;
  transition: opacity var(--duration-interact) var(--ease-out);
  pointer-events: none;
}
.product-card:hover .product-card-glow { opacity: 1; }

/* ========================================
   4-5b. PRODUCT DETAIL
   ======================================== */
.product-detail { background: var(--bg-secondary); }
.product-detail-alt { background: var(--bg-primary); }
.product-detail-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-7);
  align-items: start;
}
.gallery-main {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  aspect-ratio: 4 / 3;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-4);
}
.gallery-main img {
  max-width: 100%;
  max-height: 100%;
  object-fit: contain;
  mix-blend-mode: screen;
  transition: opacity 0.3s var(--ease-out);
}
.gallery-placeholder-main {
  aspect-ratio: 4 / 3;
  display: flex;
  align-items: center;
  justify-content: center;
}
.gallery-placeholder-main svg {
  width: 100%;
  height: 100%;
}
.gallery-thumbs {
  display: flex;
  gap: 0.5rem;
  margin-top: var(--space-3);
}
.gallery-thumb {
  width: 64px;
  height: 48px;
  border: 1px solid var(--border);
  border-radius: 6px;
  overflow: hidden;
  opacity: 0.5;
  transition: all 0.3s var(--ease-out);
  padding: 4px;
  background: var(--bg-card);
}
.gallery-thumb:hover { opacity: 0.8; }
.gallery-thumb.active {
  opacity: 1;
  border-color: var(--accent);
}
.gallery-thumb img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  mix-blend-mode: screen;
}
.product-detail-tag {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.2em;
  color: var(--accent);
  display: block;
  margin-bottom: var(--space-3);
}
.product-detail-title {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 700;
  letter-spacing: -0.04em;
  line-height: 1.15;
  margin-bottom: var(--space-4);
}
.product-detail-desc {
  color: var(--text-secondary);
  font-size: 1rem;
  line-height: 1.7;
  margin-bottom: var(--space-5);
}
.product-features {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  margin-bottom: var(--space-5);
}
.feature-item {
  display: flex;
  gap: var(--space-3);
  align-items: flex-start;
}
.feature-icon {
  flex-shrink: 0;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg-card);
}
.feature-item h4 {
  font-size: 0.9375rem;
  font-weight: 600;
  margin-bottom: 0.25rem;
}
.feature-item p {
  font-size: 0.8125rem;
  color: var(--text-secondary);
}
.product-specs {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-3);
}
.spec-item {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: var(--space-3);
  text-align: center;
}
.spec-value {
  display: block;
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  margin-bottom: 0.25rem;
}
.spec-value small {
  font-size: 0.75rem;
  font-weight: 400;
  color: var(--text-secondary);
  margin-left: 2px;
}
.spec-label {
  font-size: 0.75rem;
  color: var(--text-secondary);
}

/* ========================================
   6. ARC AI
   ======================================== */
.arc-ai-section { background: var(--bg-primary); }
.arc-panel {
  position: relative;
  min-height: 85vh;
  display: flex;
  align-items: center;
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
}

/* ========================================
   7. CASES
   ======================================== */
.cases { background: var(--bg-secondary); }
.case-item {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-6);
  align-items: center;
  margin-bottom: var(--space-7);
}
.case-item:last-child { margin-bottom: 0; }
.case-item-reverse .case-image { order: 2; }
.case-item-reverse .case-content { order: 1; }
.case-image {
  border-radius: 12px;
  overflow: hidden;
  aspect-ratio: 16 / 10;
}
.case-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.6s var(--ease-out);
}
.case-item:hover .case-image img { transform: scale(1.05); }
.case-tag {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.15em;
  color: var(--accent);
  margin-bottom: var(--space-2);
}
.case-title {
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  margin-bottom: var(--space-3);
}
.case-desc {
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: var(--space-4);
}

/* ========================================
   8. NEWS
   ======================================== */
.news { background: var(--bg-primary); }
.news-featured {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: var(--space-5);
  margin-bottom: var(--space-6);
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
}
.news-featured-image {
  aspect-ratio: 16 / 10;
  overflow: hidden;
}
.news-featured-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.news-featured-content {
  padding: var(--space-5) var(--space-5) var(--space-5) 0;
  display: flex;
  flex-direction: column;
  justify-content: center;
}
.news-date {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent);
  letter-spacing: 0.1em;
  margin-bottom: var(--space-2);
  display: block;
}
.news-title {
  font-size: clamp(1.25rem, 2.5vw, 1.75rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: var(--space-3);
  line-height: 1.3;
}
.news-excerpt {
  color: var(--text-secondary);
  line-height: 1.7;
}
.news-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-4);
}
.news-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  transition: all var(--duration-interact) var(--ease-out);
}
.news-card:hover { transform: translateY(-4px); border-color: var(--border-light); }
.news-card-image {
  aspect-ratio: 16 / 9;
  overflow: hidden;
}
.news-card-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.news-card-body { padding: var(--space-4); }
.news-card-title {
  font-size: 1.0625rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
  line-height: 1.4;
}
.news-card-excerpt {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ========================================
   9. ABOUT
   ======================================== */
.about { background: var(--bg-primary); padding-bottom: var(--space-8); }
.about-contact {
  padding: var(--space-8) 0;
  border-bottom: 1px solid var(--border);
  margin-bottom: var(--space-6);
}
.contact-layout {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: var(--space-7);
  align-items: center;
}
.contact-info .section-title { text-align: left; }
.contact-info .section-tag { text-align: left; }
.about-intro {
  font-size: 1.0625rem;
  color: var(--text-secondary);
  line-height: 1.8;
  margin-top: var(--space-4);
  max-width: 560px;
}
.contact-details {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  margin-top: var(--space-5);
}
.contact-item {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: 1.125rem;
  color: var(--text-primary);
}
.contact-qr {
  text-align: center;
}
.contact-qr img {
  width: 200px;
  height: auto;
  border-radius: 12px;
}
.contact-qr-label {
  font-size: 0.8125rem;
  color: var(--text-secondary);
  margin-top: var(--space-2);
}
.team-title {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: var(--space-5);
  text-align: center;
}
.team-gallery {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-3);
}
.team-photo {
  border-radius: 8px;
  overflow: hidden;
  aspect-ratio: 4 / 3;
}
.team-photo img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: grayscale(1);
  transition: filter 0.5s var(--ease-out), transform 0.5s var(--ease-out);
}
.team-photo:hover img {
  filter: grayscale(0);
  transform: scale(1.05);
}

/* ========================================
   10. FOOTER
   ======================================== */
.footer {
  background: #080808;
  border-top: 1px solid var(--border);
  padding: var(--space-7) 0 var(--space-4);
}
.footer-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1fr;
  gap: var(--space-6);
  margin-bottom: var(--space-6);
}
.footer-tagline {
  color: var(--text-secondary);
  font-size: 0.875rem;
  line-height: 1.6;
}
.footer-col h4 {
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: var(--space-3);
  color: var(--text-primary);
}
.footer-col li {
  margin-bottom: 0.625rem;
}
.footer-col a, .footer-col li {
  font-size: 0.8125rem;
  color: var(--text-secondary);
  transition: color 0.3s;
}
.footer-col a:hover { color: var(--accent); }
.footer-bottom {
  border-top: 1px solid var(--border);
  padding-top: var(--space-4);
  text-align: center;
}
.footer-bottom p {
  font-size: 0.75rem;
  color: var(--text-secondary);
}

/* ========================================
   VIDEO MODAL
   ======================================== */
.video-modal {
  position: fixed;
  inset: 0;
  z-index: 2000;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.4s var(--ease-out);
}
.video-modal.active { opacity: 1; pointer-events: all; }
.video-modal-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.9);
}
.video-modal-content {
  position: relative;
  width: 90vw;
  max-width: 960px;
  aspect-ratio: 16 / 9;
}
.video-modal-close {
  position: absolute;
  top: -40px;
  right: 0;
  font-size: 2rem;
  color: var(--text-secondary);
  transition: color 0.3s;
  line-height: 1;
}
.video-modal-close:hover { color: var(--text-primary); }
.video-modal-player {
  width: 100%;
  height: 100%;
  border-radius: 8px;
  background: #000;
}

/* ========================================
   SCROLL ANIMATIONS
   ======================================== */
.reveal-up {
  opacity: 0;
  transform: translateY(60px);
  transition: opacity var(--duration-enter) var(--ease-expo),
              transform var(--duration-enter) var(--ease-expo);
  transition-delay: var(--delay, 0s);
}
.reveal-up.visible {
  opacity: 1;
  transform: translateY(0);
}
.reveal-fade {
  opacity: 0;
  transition: opacity var(--duration-enter) var(--ease-expo);
  transition-delay: var(--delay, 0s);
}
.reveal-fade.visible { opacity: 1; }

/* ========================================
   RESPONSIVE — Tablet
   ======================================== */
@media (max-width: 1024px) {
  .product-grid { grid-template-columns: repeat(2, 1fr); }
  .product-grid .product-card:last-child { grid-column: span 2; max-width: 50%; margin: 0 auto; }
  .product-detail-layout { grid-template-columns: 1fr; gap: var(--space-5); }
  .product-specs { grid-template-columns: repeat(3, 1fr); }
  .case-item { grid-template-columns: 1fr; gap: var(--space-4); }
  .case-item-reverse .case-image { order: 0; }
  .case-item-reverse .case-content { order: 0; }
  .news-featured { grid-template-columns: 1fr; }
  .news-featured-content { padding: var(--space-4); }
  .footer-grid { grid-template-columns: repeat(2, 1fr); }
  .team-gallery { grid-template-columns: repeat(3, 1fr); }
}

/* ========================================
   RESPONSIVE — Mobile
   ======================================== */
@media (max-width: 768px) {
  :root { --nav-height: 60px; }
  .nav-links, .nav-cta, .navbar .lang-toggle { display: none; }
  .nav-hamburger { display: flex; }
  .hero { height: 56.25vw; min-height: 300px; max-height: 100vh; }
  .hero-video { object-position: center 30%; }
  .hero-title { font-size: 2.5rem; }
  .hero-ctas { flex-direction: column; align-items: center; }
  .product-grid { grid-template-columns: 1fr; }
  .product-grid .product-card:last-child { grid-column: span 1; max-width: 100%; }
  .product-specs { grid-template-columns: repeat(2, 1fr); }
  .news-grid { grid-template-columns: 1fr; }
  .contact-layout { grid-template-columns: 1fr; text-align: center; }
  .contact-info .section-title, .contact-info .section-tag { text-align: center; }
  .about-intro { max-width: 100%; }
  .contact-details { align-items: center; }
  .footer-grid { grid-template-columns: 1fr; gap: var(--space-4); }
  .team-gallery { grid-template-columns: repeat(2, 1fr); }
  .arc-panel { min-height: 70vh; }
  .section { padding: var(--space-6) 0; }

  /* Simplify animations on mobile */
  .reveal-up { transform: translateY(30px); }
  :root { --duration-enter: 800ms; }
}

/* ========================================
   SCROLLBAR
   ======================================== */
::-webkit-scrollbar { width: 8px; }
::-webkit-scrollbar-track { background: var(--bg-primary); }
::-webkit-scrollbar-thumb { background: var(--border-light); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-secondary); }

/* Selection */
::selection { background: rgba(45, 39, 227, 0.3); color: var(--text-primary); }