/* ============================================================
   SF Express — Premium Enterprise Visual System
   Black / White / Deep Gray + Brand Red
   ============================================================ */
:root {
  --red: #C41220;
  --red-dark: #9A0E18;
  --red-soft: rgba(196, 18, 32, 0.12);
  --black: #0A0A0B;
  --near-black: #111113;
  --dark: #1A1A1D;
  --gray-900: #2A2A2E;
  --gray-600: #6B6B70;
  --gray-400: #9A9AA0;
  --gray-200: #E8E8EA;
  --gray-100: #F4F4F5;
  --white: #FFFFFF;
  --font: 'Noto Sans SC', 'Inter', system-ui, -apple-system, sans-serif;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --header-h: 72px;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: var(--font);
  color: var(--black);
  background: var(--white);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
img { max-width: 100%; display: block; }
a { text-decoration: none; color: inherit; }
ul { list-style: none; }
button { font-family: inherit; cursor: pointer; border: none; background: none; }

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}
@media (min-width: 768px) { .container { padding: 0 40px; } }
@media (min-width: 1200px) { .container { padding: 0 48px; } }

/* Scroll progress */
.scroll-progress {
  position: fixed; top: 0; left: 0; height: 2px;
  background: var(--red); width: 0; z-index: 9999;
  transition: width 0.1s linear;
}

/* Header */
.header {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  height: var(--header-h);
  transition: background 0.4s var(--ease), box-shadow 0.4s var(--ease);
}
.header.scrolled {
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  box-shadow: 0 1px 0 rgba(0,0,0,0.06);
}
.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: var(--header-h);
}
.logo {
  display: flex; align-items: center; gap: 10px;
  font-weight: 700; font-size: 1.05rem; letter-spacing: -0.02em;
  color: var(--white); transition: color 0.3s;
}
.header.scrolled .logo { color: var(--black); }
.logo img { border-radius: 50%; }
.nav {
  display: none; gap: 28px;
}
@media (min-width: 960px) {
  .nav { display: flex; }
}
.nav a {
  font-size: 0.875rem; font-weight: 500;
  color: rgba(255,255,255,0.85); transition: color 0.25s;
  letter-spacing: 0.01em;
}
.header.scrolled .nav a { color: var(--gray-600); }
.nav a:hover { color: var(--red); }
.header.scrolled .nav a:hover { color: var(--red); }

.header-right { display: flex; align-items: center; gap: 16px; }
.lang-switch {
  display: flex; border: 1px solid rgba(255,255,255,0.25);
  border-radius: 100px; overflow: hidden;
}
.header.scrolled .lang-switch { border-color: var(--gray-200); }
.lang-btn {
  padding: 5px 12px; font-size: 0.75rem; font-weight: 600;
  color: rgba(255,255,255,0.7); transition: all 0.25s;
}
.header.scrolled .lang-btn { color: var(--gray-600); }
.lang-btn.active {
  background: var(--red); color: var(--white) !important;
}
.menu-toggle {
  display: flex; flex-direction: column; gap: 5px; padding: 8px;
}
@media (min-width: 960px) { .menu-toggle { display: none; } }
.menu-toggle span {
  display: block; width: 22px; height: 2px;
  background: var(--white); transition: all 0.3s;
}
.header.scrolled .menu-toggle span { background: var(--black); }
.menu-toggle.active span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.menu-toggle.active span:nth-child(2) { opacity: 0; }
.menu-toggle.active span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* Mobile nav */
@media (max-width: 959px) {
  .nav {
    display: none; position: fixed; top: var(--header-h); left: 0; right: 0;
    background: var(--white); flex-direction: column; padding: 24px;
    gap: 0; box-shadow: 0 12px 40px rgba(0,0,0,0.1);
  }
  .nav.open { display: flex; }
  .nav a {
    color: var(--black) !important; padding: 14px 0;
    border-bottom: 1px solid var(--gray-100); font-size: 1rem;
  }
}

/* ========== HERO ========== */
.hero {
  position: relative; min-height: 100vh; min-height: 100dvh;
  display: flex; align-items: center; justify-content: center;
  overflow: hidden; background: var(--black);
}
.hero-bg { position: absolute; inset: 0; }
.hero-slide {
  position: absolute; inset: 0;
  background-size: cover; background-position: center;
  opacity: 0; transform: scale(1.08);
  transition: opacity 1.4s var(--ease), transform 8s linear;
}
.hero-slide.active {
  opacity: 1; transform: scale(1);
}
.hero-overlay {
  position: absolute; inset: 0;
  background:
    linear-gradient(180deg, rgba(10,10,11,0.55) 0%, rgba(10,10,11,0.35) 40%, rgba(10,10,11,0.7) 100%),
    radial-gradient(ellipse at 30% 20%, rgba(196,18,32,0.18), transparent 55%);
}
.hero-content {
  position: relative; z-index: 2; text-align: center;
  max-width: 820px; padding: 0 24px; color: var(--white);
  will-change: transform, opacity;
}
.hero-badge {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 6px 16px; border-radius: 100px;
  background: rgba(255,255,255,0.08); border: 1px solid rgba(255,255,255,0.15);
  font-size: 0.8rem; font-weight: 500; letter-spacing: 0.04em;
  margin-bottom: 28px; color: rgba(255,255,255,0.9);
}
.badge-dot {
  width: 6px; height: 6px; border-radius: 50%;
  background: var(--red); box-shadow: 0 0 8px var(--red);
  animation: pulse-dot 2s ease infinite;
}
@keyframes pulse-dot {
  0%, 100% { opacity: 1; } 50% { opacity: 0.4; }
}
.hero-title {
  font-size: clamp(2.5rem, 8vw, 4.5rem);
  font-weight: 700; line-height: 1.15; letter-spacing: -0.03em;
  margin-bottom: 20px;
}
.hero-sub {
  font-size: clamp(0.95rem, 2.2vw, 1.15rem);
  font-weight: 400; color: rgba(255,255,255,0.7);
  letter-spacing: 0.02em; margin-bottom: 12px;
}
.hero-desc {
  font-size: 0.95rem; color: rgba(255,255,255,0.55);
  margin-bottom: 36px;
}
.hero-cta { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }

.btn-primary {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 14px 32px; background: var(--red); color: var(--white);
  font-size: 0.9rem; font-weight: 600; border-radius: 100px;
  transition: background 0.3s, transform 0.3s var(--ease), box-shadow 0.3s;
}
.btn-primary:hover {
  background: var(--red-dark); transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(196,18,32,0.35);
}
.btn-ghost {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 14px 32px; background: transparent; color: var(--white);
  font-size: 0.9rem; font-weight: 600; border-radius: 100px;
  border: 1px solid rgba(255,255,255,0.35);
  transition: border-color 0.3s, background 0.3s;
}
.btn-ghost:hover {
  border-color: rgba(255,255,255,0.7); background: rgba(255,255,255,0.06);
}

.hero-scroll {
  position: absolute; bottom: 32px; left: 50%; transform: translateX(-50%);
  z-index: 2;
}
.hero-scroll span {
  display: block; width: 20px; height: 32px;
  border: 1.5px solid rgba(255,255,255,0.35); border-radius: 10px;
  position: relative;
}
.hero-scroll span::after {
  content: ''; position: absolute; top: 6px; left: 50%;
  width: 3px; height: 6px; margin-left: -1.5px;
  background: rgba(255,255,255,0.6); border-radius: 2px;
  animation: scroll-hint 1.8s ease infinite;
}
@keyframes scroll-hint {
  0% { opacity: 1; transform: translateY(0); }
  100% { opacity: 0; transform: translateY(10px); }
}

/* ========== SECTIONS ========== */
.section { padding: 100px 0; }
@media (min-width: 768px) { .section { padding: 140px 0; } }

.section-label {
  font-size: 0.8rem; font-weight: 600; letter-spacing: 0.12em;
  text-transform: uppercase; color: var(--red); margin-bottom: 16px;
}
.section-title-lg {
  font-size: clamp(2rem, 5vw, 3.25rem);
  font-weight: 700; line-height: 1.2; letter-spacing: -0.03em;
  color: var(--black); margin-bottom: 24px;
}
.section-desc {
  font-size: 1.05rem; color: var(--gray-600); max-width: 520px;
  line-height: 1.7;
}
.section-header { margin-bottom: 64px; }
@media (min-width: 768px) { .section-header { margin-bottom: 80px; } }

/* Vision */
.vision { background: var(--white); }
.vision-grid {
  display: grid; gap: 48px; align-items: center;
}
@media (min-width: 900px) {
  .vision-grid { grid-template-columns: 1fr 1fr; gap: 80px; }
}
.vision-body {
  font-size: 1.05rem; color: var(--gray-600); line-height: 1.8;
  margin-bottom: 40px; max-width: 480px;
}
.vision-meta { display: flex; gap: 48px; }
.meta-num {
  display: block; font-size: 2.5rem; font-weight: 700;
  letter-spacing: -0.03em; color: var(--black); line-height: 1;
}
.meta-label {
  display: block; font-size: 0.8rem; color: var(--gray-400);
  margin-top: 6px; letter-spacing: 0.02em;
}
.vision-img-wrap {
  border-radius: 4px; overflow: hidden;
  aspect-ratio: 4/5; background: var(--gray-100);
}
.vision-img-wrap img {
  width: 100%; height: 100%; object-fit: cover;
  transition: transform 1.2s var(--ease);
}
.vision-img-wrap:hover img { transform: scale(1.04); }

/* Stats */
.stats-section {
  background: var(--black); color: var(--white);
}
.stats-section .section-title-lg { color: var(--white); }
.stats-grid {
  display: grid; grid-template-columns: 1fr 1fr; gap: 40px 24px;
}
@media (min-width: 768px) {
  .stats-grid { grid-template-columns: repeat(4, 1fr); gap: 32px; }
}
.stat-item { text-align: left; }
.stat-num {
  font-size: clamp(2.5rem, 6vw, 3.75rem);
  font-weight: 700; letter-spacing: -0.04em; line-height: 1;
  color: var(--white); margin-bottom: 12px;
}
.stat-label {
  font-size: 0.9rem; color: rgba(255,255,255,0.55);
  margin-bottom: 6px;
}
.stat-change {
  font-size: 0.85rem; font-weight: 600; color: var(--red);
}

/* Services */
.services { background: var(--gray-100); }
.svc-grid {
  display: grid; gap: 2px;
  grid-template-columns: 1fr;
}
@media (min-width: 640px) { .svc-grid { grid-template-columns: 1fr 1fr; } }
@media (min-width: 960px) { .svc-grid { grid-template-columns: repeat(4, 1fr); } }
.svc-card {
  background: var(--white); padding: 40px 32px;
  transition: transform 0.4s var(--ease), box-shadow 0.4s var(--ease);
  border: 1px solid transparent;
}
.svc-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 20px 48px rgba(0,0,0,0.08);
  border-color: var(--gray-200);
}
.svc-num {
  font-size: 0.8rem; font-weight: 700; color: var(--red);
  letter-spacing: 0.08em; margin-bottom: 20px;
}
.svc-card h3 {
  font-size: 1.2rem; font-weight: 700; margin-bottom: 12px;
  letter-spacing: -0.02em;
}
.svc-card p {
  font-size: 0.9rem; color: var(--gray-600); line-height: 1.7;
}

/* Gallery */
.gallery-section { background: var(--white); padding-bottom: 0; }
.gallery-strip {
  display: grid; grid-template-columns: repeat(2, 1fr); gap: 4px;
}
@media (min-width: 640px) { .gallery-strip { grid-template-columns: repeat(3, 1fr); } }
@media (min-width: 960px) { .gallery-strip { grid-template-columns: repeat(6, 1fr); } }
.gallery-item {
  aspect-ratio: 3/4; overflow: hidden; background: var(--gray-100);
}
.gallery-item img {
  width: 100%; height: 100%; object-fit: cover;
  transition: transform 0.8s var(--ease);
}
.gallery-item:hover img { transform: scale(1.06); }

/* Network */
.network { background: var(--near-black); color: var(--white); }
.network .section-title-lg { color: var(--white); }
.network .section-desc { color: rgba(255,255,255,0.5); }
.network-visual { margin-top: 48px; }
.net-map {
  position: relative; height: 200px; margin-bottom: 64px;
  display: flex; align-items: center; justify-content: center;
}
@media (min-width: 768px) { .net-map { height: 240px; } }
.net-node {
  position: absolute; width: 72px; height: 72px;
  border-radius: 50%; background: var(--dark);
  border: 1px solid rgba(255,255,255,0.12);
  display: flex; align-items: center; justify-content: center;
  font-size: 0.8rem; font-weight: 600; color: rgba(255,255,255,0.85);
  z-index: 2;
}
.net-node.n1 { left: 10%; background: var(--red); border-color: var(--red); }
.net-node.n2 { left: 50%; transform: translateX(-50%); }
.net-node.n3 { right: 10%; }
.net-line {
  position: absolute; height: 1px;
  background: linear-gradient(90deg, transparent, rgba(196,18,32,0.5), transparent);
  top: 50%; z-index: 1;
}
.net-line.l1 { left: 15%; width: 30%; }
.net-line.l2 { left: 55%; width: 30%; }
.net-stats {
  display: grid; grid-template-columns: 1fr; gap: 32px;
}
@media (min-width: 640px) { .net-stats { grid-template-columns: repeat(3, 1fr); gap: 24px; } }
.net-stat-num {
  display: block; font-size: 2rem; font-weight: 700;
  letter-spacing: -0.03em; margin-bottom: 8px;
}
.net-stat-label {
  font-size: 0.85rem; color: rgba(255,255,255,0.5);
}

/* Tech */
.tech { background: var(--white); }
.tech-grid {
  display: grid; gap: 48px; align-items: start;
}
@media (min-width: 900px) {
  .tech-grid { grid-template-columns: 1fr 1fr; gap: 80px; }
}
.tech-body {
  font-size: 1.05rem; color: var(--gray-600); line-height: 1.8;
  margin-bottom: 32px; max-width: 480px;
}
.tech-list li {
  position: relative; padding-left: 20px; margin-bottom: 12px;
  font-size: 0.95rem; color: var(--gray-600);
}
.tech-list li::before {
  content: ''; position: absolute; left: 0; top: 10px;
  width: 6px; height: 6px; border-radius: 50%; background: var(--red);
}
.tech-visual {
  display: grid; gap: 16px;
}
.tech-card {
  padding: 28px 32px; background: var(--gray-100);
  border-radius: 4px; transition: background 0.3s;
}
.tech-card:hover { background: var(--gray-200); }
.tech-card-icon {
  font-size: 0.75rem; font-weight: 700; letter-spacing: 0.1em;
  color: var(--red); margin-bottom: 12px;
}
.tech-card h4 {
  font-size: 1.1rem; font-weight: 700; margin-bottom: 4px;
}
.tech-card p { font-size: 0.85rem; color: var(--gray-600); }

/* Strength */
.strength { background: var(--gray-100); }
.strength-list { display: flex; flex-direction: column; gap: 2px; }
.strength-item {
  display: grid; gap: 24px; background: var(--white);
  padding: 40px 32px; align-items: center;
}
@media (min-width: 768px) {
  .strength-item {
    grid-template-columns: 80px 1fr 280px; gap: 40px; padding: 48px 40px;
  }
}
.strength-num {
  font-size: 1.5rem; font-weight: 700; color: var(--red);
  letter-spacing: -0.02em;
}
.strength-content h3 {
  font-size: 1.35rem; font-weight: 700; margin-bottom: 10px;
  letter-spacing: -0.02em;
}
.strength-content p {
  font-size: 0.95rem; color: var(--gray-600); line-height: 1.7;
  max-width: 420px;
}
.strength-img {
  border-radius: 4px; overflow: hidden; aspect-ratio: 16/10;
  background: var(--gray-100); display: none;
}
@media (min-width: 768px) { .strength-img { display: block; } }
.strength-img img {
  width: 100%; height: 100%; object-fit: cover;
  transition: transform 0.8s var(--ease);
}
.strength-item:hover .strength-img img { transform: scale(1.05); }

/* Videos */
.videos { background: var(--white); }
.video-grid {
  display: grid; gap: 32px;
}
@media (min-width: 768px) { .video-grid { grid-template-columns: repeat(3, 1fr); gap: 24px; } }
.video-wrap {
  border-radius: 4px; overflow: hidden; background: var(--black);
  aspect-ratio: 16/9; margin-bottom: 16px;
}
.video-wrap video { width: 100%; height: 100%; object-fit: cover; display: block; }
.video-card h3 {
  font-size: 1.05rem; font-weight: 700; margin-bottom: 4px;
}
.video-card p { font-size: 0.85rem; color: var(--gray-600); }

/* CTA */
.cta-section {
  background: var(--black); color: var(--white); text-align: center;
  padding: 120px 0;
}
.cta-box h2 {
  font-size: clamp(1.75rem, 4vw, 2.75rem); font-weight: 700;
  letter-spacing: -0.03em; margin-bottom: 16px;
}
.cta-box p {
  font-size: 1rem; color: rgba(255,255,255,0.5); margin-bottom: 36px;
}

/* Footer */
.footer {
  background: var(--near-black); color: rgba(255,255,255,0.5);
  padding: 48px 0 32px;
}
.footer-top {
  display: flex; flex-wrap: wrap; align-items: center;
  justify-content: space-between; gap: 16px; margin-bottom: 32px;
}
.footer-brand {
  display: flex; align-items: center; gap: 10px;
  color: var(--white); font-weight: 700; font-size: 0.95rem;
}
.footer-brand img { border-radius: 50%; opacity: 0.9; }
.footer-note { font-size: 0.8rem; }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.08);
  padding-top: 24px; font-size: 0.8rem;
}

/* ========== ANIMATIONS ========== */
.reveal, .reveal-up {
  opacity: 0; transform: translateY(32px);
  transition: opacity 0.9s var(--ease), transform 0.9s var(--ease);
}
.reveal-up { transform: translateY(40px); }
.reveal.visible, .reveal-up.visible {
  opacity: 1; transform: translateY(0);
}

/* Stagger children */
.stats-grid .stat-item:nth-child(1) { transition-delay: 0s; }
.stats-grid .stat-item:nth-child(2) { transition-delay: 0.08s; }
.stats-grid .stat-item:nth-child(3) { transition-delay: 0.16s; }
.stats-grid .stat-item:nth-child(4) { transition-delay: 0.24s; }
.svc-grid .svc-card:nth-child(1) { transition-delay: 0s; }
.svc-grid .svc-card:nth-child(2) { transition-delay: 0.06s; }
.svc-grid .svc-card:nth-child(3) { transition-delay: 0.12s; }
.svc-grid .svc-card:nth-child(4) { transition-delay: 0.18s; }

/* Page enter */
body { animation: page-in 0.9s var(--ease); }
@keyframes page-in {
  from { opacity: 0; } to { opacity: 1; }
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}