/* YUDONG TECHNOLOGY - Dark Tech Theme - Distinct from others */
@import url('https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@400;500;600;700&family=DM+Sans:wght@300;400;500;600&display=swap');

:root {
  --dark-bg: #0f172a;
  --dark-card: #1e293b;
  --dark-elevated: #334155;
  --accent: #06b6d4;
  --accent-light: #22d3ee;
  --text: #e2e8f0;
  --text-muted: #94a3b8;
  --text-dim: #64748b;
  --border: rgba(148, 163, 184, 0.2);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  font-family: 'DM Sans', sans-serif;
  background: var(--dark-bg);
  color: var(--text);
  line-height: 1.7;
  overflow-x: hidden;
}

/* Header - Minimal dark bar, underline accent */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  background: rgba(15, 23, 42, 0.9);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  padding: 1rem 2.5rem;
}
.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.logo {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--accent);
  text-decoration: none;
  letter-spacing: 0.05em;
}
.logo span { color: var(--text-muted); font-weight: 500; }
.nav-menu {
  display: flex;
  gap: 2.5rem;
  list-style: none;
}
.nav-menu a {
  color: var(--text-muted);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.9rem;
  transition: color 0.2s;
  position: relative;
}
.nav-menu a::after {
  content: '';
  position: absolute;
  bottom: -4px; left: 0;
  width: 0;
  height: 2px;
  background: var(--accent);
  transition: width 0.3s;
}
.nav-menu a:hover, .nav-menu a.active { color: var(--text); }
.nav-menu a:hover::after, .nav-menu a.active::after { width: 100%; }
.menu-toggle { display: none; background: none; border: none; font-size: 1.5rem; cursor: pointer; color: var(--text); }

/* Hero - Diagonal split, text left, visual right */
.hero-diagonal {
  min-height: 92vh;
  display: grid;
  grid-template-columns: 1fr 1.1fr;
  position: relative;
  margin-top: 60px;
}
.hero-diagonal::before {
  content: '';
  position: absolute;
  top: 0; right: 0;
  width: 55%;
  height: 100%;
  background: linear-gradient(135deg, var(--dark-card) 0%, var(--dark-bg) 100%);
  clip-path: polygon(15% 0, 100% 0, 100% 100%, 0 100%);
  z-index: 0;
}
.hero-text-block {
  padding: 6rem 4rem 4rem;
  display: flex;
  flex-direction: column;
  justify-content: center;
  position: relative;
  z-index: 1;
}
.hero-tag {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.3em;
  color: var(--accent);
  margin-bottom: 1.25rem;
}
.hero-text-block h1 {
  font-family: 'Space Grotesk', sans-serif;
  font-size: clamp(2.2rem, 4vw, 3.4rem);
  font-weight: 700;
  color: var(--text);
  line-height: 1.15;
  margin-bottom: 1.5rem;
}
.hero-text-block .hero-desc {
  color: var(--text-muted);
  font-size: 1.05rem;
  max-width: 480px;
  margin-bottom: 2rem;
}
.hero-btn {
  display: inline-block;
  padding: 0.9rem 2rem;
  background: var(--accent);
  color: var(--dark-bg);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.9rem;
  border-radius: 6px;
  transition: background 0.2s, transform 0.2s;
  width: fit-content;
}
.hero-btn:hover { background: var(--accent-light); transform: translateY(-2px); }

.hero-visual-block {
  position: relative;
  z-index: 1;
  overflow: hidden;
}
.hero-carousel-wrap {
  position: relative;
  height: 100%;
  min-height: 500px;
}
.hero-slide {
  position: absolute;
  inset: 0;
  opacity: 0;
  transition: opacity 0.6s ease;
}
.hero-slide.active { opacity: 1; z-index: 1; }
.hero-slide img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.hero-dots {
  position: absolute;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 0.75rem;
  z-index: 2;
}
.hero-dots span {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: rgba(148, 163, 184, 0.4);
  cursor: pointer;
  transition: all 0.3s;
}
.hero-dots span:hover, .hero-dots span.active {
  background: var(--accent);
  transform: scale(1.2);
}

/* Container */
.container { max-width: 1200px; margin: 0 auto; padding: 0 2rem; }

/* Section common */
.sect-tag {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.25em;
  color: var(--accent);
  margin-bottom: 0.75rem;
}
.sect-title {
  font-family: 'Space Grotesk', sans-serif;
  font-size: clamp(1.8rem, 3vw, 2.4rem);
  font-weight: 700;
  color: var(--text);
  margin-bottom: 2.5rem;
}

/* Products - 4-col fixed grid, glass cards */
.products-section {
  padding: 6rem 0;
  background: var(--dark-bg);
}
.products-grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.5rem;
}
.prod-card-glass {
  background: rgba(30, 41, 59, 0.6);
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  transition: all 0.3s;
}
.prod-card-glass:hover {
  border-color: rgba(6, 182, 212, 0.4);
  transform: translateY(-4px);
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
}
.prod-card-glass img {
  width: 100%;
  height: 220px;
  object-fit: cover;
}
.prod-caption { padding: 1.25rem; }
.prod-caption h3 {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 1rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 0.4rem;
}
.prod-caption p {
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* About - Single large image + overlay text */
.about-banner {
  padding: 6rem 0;
  background: var(--dark-card);
}
.about-banner-inner {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 4rem;
  align-items: center;
}
.about-visual {
  position: relative;
  border-radius: 16px;
  overflow: hidden;
  box-shadow: 0 25px 50px rgba(0, 0, 0, 0.4);
}
.about-visual img {
  width: 100%;
  height: 380px;
  object-fit: cover;
}
.about-content h2 { margin-bottom: 1.5rem; }
.about-content p {
  color: var(--text-muted);
  margin-bottom: 1.25rem;
}

/* Testimonials - Horizontal scroll strip, glass cards */
.testimonials-section {
  padding: 6rem 0;
  background: var(--dark-bg);
}
.testimonial-strip {
  display: flex;
  gap: 1.5rem;
  overflow-x: auto;
  padding-bottom: 1rem;
  scroll-snap-type: x mandatory;
  -webkit-overflow-scrolling: touch;
}
.testimonial-strip::-webkit-scrollbar { height: 6px; }
.testimonial-strip::-webkit-scrollbar-track { background: var(--dark-elevated); border-radius: 3px; }
.testimonial-strip::-webkit-scrollbar-thumb { background: var(--accent); border-radius: 3px; }
.testimonial-box {
  flex: 0 0 340px;
  background: rgba(30, 41, 59, 0.7);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.75rem;
  scroll-snap-align: start;
  transition: border-color 0.2s;
}
.testimonial-box:hover { border-color: rgba(6, 182, 212, 0.3); }
.testimonial-stars {
  color: #fbbf24;
  font-size: 0.9rem;
  margin-bottom: 1rem;
}
.testimonial-box p {
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.7;
  margin-bottom: 1.25rem;
}
.testimonial-author {
  display: flex;
  align-items: center;
  gap: 1rem;
}
.testimonial-avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  overflow: hidden;
  flex-shrink: 0;
}
.testimonial-avatar img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.testimonial-name { font-weight: 600; color: var(--text); font-size: 0.95rem; }
.testimonial-role { font-size: 0.8rem; color: var(--text-dim); }

/* Message - Left image, right form */
.message-section {
  padding: 6rem 0;
  background: var(--dark-card);
}
.message-wrap {
  display: grid;
  grid-template-columns: 0.9fr 1fr;
  gap: 3rem;
  align-items: center;
  max-width: 1000px;
  margin: 0 auto;
}
.message-img {
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
}
.message-img img {
  width: 100%;
  height: 320px;
  object-fit: cover;
}
.message-form {
  background: rgba(15, 23, 42, 0.5);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 2rem;
}
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; }
.form-group { margin-bottom: 1.25rem; }
.form-group label {
  display: block;
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}
.form-group input,
.form-group textarea {
  width: 100%;
  padding: 0.85rem 1rem;
  background: var(--dark-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  font-family: inherit;
  font-size: 0.95rem;
}
.form-group input::placeholder,
.form-group textarea::placeholder { color: var(--text-dim); }
.form-group textarea { min-height: 120px; resize: vertical; }
.btn-send {
  padding: 0.9rem 2rem;
  background: var(--accent);
  color: var(--dark-bg);
  border: none;
  font-weight: 600;
  font-size: 0.95rem;
  border-radius: 8px;
  cursor: pointer;
  transition: background 0.2s;
}
.btn-send:hover { background: var(--accent-light); }

/* Footer */
.site-footer {
  background: var(--dark-elevated);
  border-top: 1px solid var(--border);
  padding: 4rem 2rem 2rem;
}
.footer-grid {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr;
  gap: 3rem;
  margin-bottom: 2.5rem;
}
.footer-logo {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--accent);
  text-decoration: none;
  display: block;
  margin-bottom: 1rem;
}
.footer-desc {
  color: var(--text-muted);
  font-size: 0.9rem;
  line-height: 1.7;
  margin-bottom: 1.5rem;
}
.footer-social h4, .footer-nav h4, .footer-contact h4 {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 0.9rem;
  color: var(--text);
  margin-bottom: 1rem;
}
.footer-social-links {
  display: flex;
  gap: 0.75rem;
}
.footer-social-links a {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--dark-bg);
  color: var(--accent);
  border-radius: 8px;
  text-decoration: none;
  transition: all 0.2s;
}
.footer-social-links a:hover {
  background: var(--accent);
  color: var(--dark-bg);
}
.footer-nav ul { list-style: none; }
.footer-nav a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.9rem;
  display: block;
  padding: 0.35rem 0;
  transition: color 0.2s;
}
.footer-nav a:hover { color: var(--accent); }
.footer-contact p {
  color: var(--text-muted);
  font-size: 0.9rem;
  line-height: 1.7;
}
.footer-contact a { color: var(--accent); text-decoration: none; }
.footer-contact a:hover { text-decoration: underline; }
.footer-copy {
  text-align: center;
  color: var(--text-dim);
  font-size: 0.85rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
  max-width: 1200px;
  margin: 0 auto;
}

/* Back to top */
.back-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 44px;
  height: 44px;
  background: var(--accent);
  color: var(--dark-bg);
  border: none;
  border-radius: 10px;
  font-size: 1.2rem;
  cursor: pointer;
  z-index: 999;
  transition: background 0.2s, transform 0.2s;
}
.back-top:hover { background: var(--accent-light); transform: translateY(-3px); }

/* Contact page */
.contact-banner { width: 100%; height: 320px; object-fit: cover; }
.contact-main {
  padding: 4rem 0;
}
.contact-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: start;
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 2rem;
}
.contact-img-wrap {
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.4);
}
.contact-img-wrap img {
  width: 100%;
  height: 380px;
  object-fit: cover;
}
.contact-info h2 { margin-bottom: 1.5rem; }
.contact-info p {
  color: var(--text-muted);
  margin-bottom: 1rem;
  font-size: 0.95rem;
}

/* About page */
.about-page-banner {
  height: 45vh;
  min-height: 320px;
  position: relative;
  overflow: hidden;
}
.about-page-banner img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.about-page-content {
  padding: 4rem 2rem;
  max-width: 900px;
  margin: 0 auto;
}
.about-page-content h1 {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 2.2rem;
  margin-bottom: 1.5rem;
}
.about-page-content p {
  color: var(--text-muted);
  margin-bottom: 1.25rem;
  line-height: 1.8;
}

/* Page header variant */
.site-header.page-header {
  position: relative;
  background: var(--dark-bg);
  margin-top: 0;
}

/* Responsive */
@media (max-width: 1024px) {
  .hero-diagonal {
    grid-template-columns: 1fr;
    min-height: auto;
    padding-bottom: 4rem;
  }
  .hero-diagonal::before {
    width: 100%;
    clip-path: none;
    height: 60%;
    top: auto;
    bottom: 0;
  }
  .hero-text-block { padding: 4rem 2rem 2rem; }
  .hero-visual-block { min-height: 400px; }
  .products-grid-4 { grid-template-columns: repeat(2, 1fr); }
  .about-banner-inner { grid-template-columns: 1fr; }
  .message-wrap { grid-template-columns: 1fr; }
  .message-img { order: 1; }
  .message-form { order: 2; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 768px) {
  .header-inner { padding: 0; }
  .nav-menu {
    position: fixed;
    top: 60px;
    right: -100%;
    width: 80%;
    max-width: 280px;
    height: calc(100vh - 60px);
    background: var(--dark-card);
    flex-direction: column;
    padding: 2rem;
    gap: 1.5rem;
    transition: right 0.3s;
    border-left: 1px solid var(--border);
  }
  .nav-menu.open { right: 0; }
  .menu-toggle { display: block; }
  .products-grid-4 { grid-template-columns: 1fr; }
  .form-row { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .contact-layout { grid-template-columns: 1fr; }
  .testimonial-box { flex: 0 0 300px; }
}