/* ═══════════════════════════════════════════════
   B2B Site Design System v1.0
   ═══════════════════════════════════════════════ */

/* ─── Reset & Base ─── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  /* Colors */
  --navy-900: #0A0F1C;
  --navy-800: #0F172A;
  --navy-700: #1E293B;
  --navy-600: #334155;
  --slate-500: #64748B;
  --slate-400: #94A3B8;
  --slate-300: #CBD5E1;
  --slate-200: #E2E8F0;
  --slate-100: #F1F5F9;
  --slate-50:  #F8FAFC;
  --white: #FFFFFF;

  --blue-600: #2563EB;
  --blue-500: #3B82F6;
  --cyan-500: #06B6D4;
  --cyan-400: #22D3EE;

  --accent: #2563EB;
  --accent-hover: #1D4ED8;
  --accent-light: #EFF6FF;

  --gradient-primary: linear-gradient(135deg, #06B6D4 0%, #2563EB 50%, #7C3AED 100%);
  --gradient-hero: linear-gradient(135deg, #0A0F1C 0%, #1E293B 60%, #0F172A 100%);
  --gradient-text: linear-gradient(135deg, #06B6D4, #2563EB);

  --green-500: #10B981;
  --amber-500: #F59E0B;
  --red-500: #EF4444;

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  --font-mono: 'SF Mono', 'JetBrains Mono', 'Fira Code', monospace;

  /* Spacing */
  --sp-1: 4px;  --sp-2: 8px;  --sp-3: 12px; --sp-4: 16px;
  --sp-5: 20px; --sp-6: 24px; --sp-8: 32px; --sp-10: 40px;
  --sp-12: 48px; --sp-16: 64px; --sp-20: 80px; --sp-24: 96px;

  /* Radius */
  --r-sm: 6px; --r-md: 10px; --r-lg: 14px; --r-xl: 20px; --r-full: 9999px;

  /* Shadows */
  --shadow-xs: 0 1px 2px rgba(15,23,42,0.04);
  --shadow-sm: 0 1px 3px rgba(15,23,42,0.06), 0 1px 2px rgba(15,23,42,0.04);
  --shadow-md: 0 4px 12px rgba(15,23,42,0.06), 0 2px 4px rgba(15,23,42,0.04);
  --shadow-lg: 0 12px 32px rgba(15,23,42,0.08), 0 4px 8px rgba(15,23,42,0.04);
  --shadow-xl: 0 20px 48px rgba(15,23,42,0.12), 0 8px 16px rgba(15,23,42,0.06);
  --shadow-glow: 0 0 0 4px rgba(37,99,235,0.12);

  /* Transitions */
  --t-fast: 0.15s ease;
  --t-base: 0.2s ease;
  --t-slow: 0.35s cubic-bezier(0.4, 0, 0.2, 1);

  /* Layout */
  --container: 1280px;
  --nav-h: 68px;
}

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
  font-family: var(--font-sans);
  font-size: 15px;
  line-height: 1.6;
  color: var(--navy-700);
  background: var(--white);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
button { font-family: inherit; cursor: pointer; border: none; background: none; }
input, textarea, select { font-family: inherit; font-size: inherit; }
ul, ol { list-style: none; }

.container { max-width: var(--container); margin: 0 auto; padding: 0 var(--sp-6); }

/* ─── Typography ─── */
h1, h2, h3, h4, h5 { color: var(--navy-800); font-weight: 700; line-height: 1.2; letter-spacing: -0.02em; }
h1 { font-size: clamp(32px, 5vw, 52px); font-weight: 800; }
h2 { font-size: clamp(26px, 3.5vw, 38px); }
h3 { font-size: 22px; }
h4 { font-size: 18px; }

.text-gradient {
  background: var(--gradient-text);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.section-label {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-2);
  font-size: 13px;
  font-weight: 600;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: var(--sp-3);
}
.section-label::before {
  content: '';
  width: 24px; height: 2px;
  background: var(--gradient-primary);
  border-radius: 2px;
}

.section-title { text-align: center; margin-bottom: var(--sp-4); }
.section-subtitle { text-align: center; color: var(--slate-500); font-size: 16px; max-width: 560px; margin: 0 auto var(--sp-12); }

/* ─── Buttons ─── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--sp-2);
  padding: 12px 28px;
  font-size: 14px;
  font-weight: 600;
  border-radius: var(--r-md);
  transition: all var(--t-base);
  white-space: nowrap;
  cursor: pointer;
  line-height: 1.4;
}

.btn-primary {
  background: var(--gradient-primary);
  color: var(--white);
  box-shadow: 0 4px 14px rgba(37,99,235,0.25);
}
.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(37,99,235,0.35);
}
.btn-primary:active { transform: translateY(0); }

.btn-secondary {
  background: var(--white);
  color: var(--navy-700);
  border: 1.5px solid var(--slate-200);
}
.btn-secondary:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-light);
}

.btn-ghost {
  background: transparent;
  color: var(--slate-500);
  padding: 8px 16px;
}
.btn-ghost:hover { color: var(--navy-700); background: var(--slate-100); }

.btn-lg { padding: 14px 36px; font-size: 15px; border-radius: var(--r-lg); }
.btn-sm { padding: 8px 18px; font-size: 13px; }

/* ─── Navigation ─── */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--nav-h);
  background: rgba(255,255,255,0.85);
  backdrop-filter: saturate(180%) blur(16px);
  -webkit-backdrop-filter: saturate(180%) blur(16px);
  border-bottom: 1px solid var(--slate-200);
  z-index: 100;
  transition: box-shadow var(--t-base);
}
.nav.scrolled { box-shadow: var(--shadow-sm); }

.nav-inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 var(--sp-6);
  height: 100%;
  display: flex;
  align-items: center;
  gap: var(--sp-8);
}

.nav-logo {
  font-size: 20px;
  font-weight: 800;
  letter-spacing: -0.02em;
  display: flex;
  align-items: center;
  gap: var(--sp-2);
  flex-shrink: 0;
}
.nav-logo .logo-mark {
  width: 34px; height: 34px;
  background: var(--gradient-primary);
  border-radius: var(--r-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 16px;
  font-weight: 800;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--sp-1);
  margin-left: auto;
}
.nav-links a {
  padding: 8px 16px;
  font-size: 14px;
  font-weight: 500;
  color: var(--slate-500);
  border-radius: var(--r-sm);
  transition: all var(--t-fast);
}
.nav-links a:hover { color: var(--navy-800); background: var(--slate-100); }
.nav-links a.active { color: var(--accent); background: var(--accent-light); }

.nav-actions { display: flex; align-items: center; gap: var(--sp-3); flex-shrink: 0; }

.lang-switch {
  display: inline-flex;
  background: var(--slate-100);
  border-radius: var(--r-full);
  padding: 3px;
  gap: 2px;
}
.lang-switch a {
  padding: 5px 12px;
  font-size: 12px;
  font-weight: 600;
  color: var(--slate-500);
  border-radius: var(--r-full);
  transition: all var(--t-fast);
  text-transform: uppercase;
}
.lang-switch a.active {
  background: var(--white);
  color: var(--navy-800);
  box-shadow: var(--shadow-xs);
}

.nav-toggle { display: none; }

/* ─── Hero ─── */
.hero {
  position: relative;
  background: var(--gradient-hero);
  padding: calc(var(--nav-h) + var(--sp-20)) 0 var(--sp-24);
  overflow: hidden;
  color: var(--white);
}
.hero::before {
  content: '';
  position: absolute;
  top: -200px; right: -200px;
  width: 600px; height: 600px;
  background: radial-gradient(circle, rgba(6,182,212,0.15) 0%, transparent 70%);
  border-radius: 50%;
}
.hero::after {
  content: '';
  position: absolute;
  bottom: -300px; left: -100px;
  width: 500px; height: 500px;
  background: radial-gradient(circle, rgba(124,58,237,0.1) 0%, transparent 70%);
  border-radius: 50%;
}

.hero-inner { position: relative; z-index: 1; max-width: 800px; }
.hero h1 { color: var(--white); margin-bottom: var(--sp-5); }
.hero h1 .highlight {
  background: linear-gradient(135deg, #22D3EE, #60A5FA);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero p {
  font-size: 18px;
  color: rgba(255,255,255,0.7);
  line-height: 1.7;
  margin-bottom: var(--sp-8);
  max-width: 600px;
}
.hero-actions { display: flex; gap: var(--sp-3); flex-wrap: wrap; }
.hero .btn-secondary {
  background: rgba(255,255,255,0.08);
  border-color: rgba(255,255,255,0.15);
  color: var(--white);
}
.hero .btn-secondary:hover {
  background: rgba(255,255,255,0.15);
  border-color: rgba(255,255,255,0.3);
  color: var(--white);
}

.hero-stats {
  display: flex;
  gap: var(--sp-12);
  margin-top: var(--sp-16);
  padding-top: var(--sp-10);
  border-top: 1px solid rgba(255,255,255,0.1);
}
.hero-stat .num {
  font-size: 32px;
  font-weight: 800;
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, #22D3EE, #60A5FA);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-stat .lbl { font-size: 13px; color: rgba(255,255,255,0.5); margin-top: 2px; }

/* ─── Sections ─── */
.section { padding: var(--sp-24) 0; }
.section-alt { background: var(--slate-50); }
.section-dark { background: var(--navy-900); color: var(--white); }
.section-dark h2 { color: var(--white); }
.section-dark .section-subtitle { color: var(--slate-400); }

/* ─── Advantage Cards ─── */
.adv-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--sp-5);
}
.adv-card {
  background: var(--white);
  border: 1px solid var(--slate-200);
  border-radius: var(--r-lg);
  padding: var(--sp-8) var(--sp-6);
  text-align: center;
  transition: all var(--t-slow);
}
.adv-card:hover {
  border-color: transparent;
  box-shadow: var(--shadow-lg);
  transform: translateY(-4px);
}
.adv-icon {
  width: 56px; height: 56px;
  margin: 0 auto var(--sp-4);
  border-radius: var(--r-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--accent-light);
  color: var(--accent);
}
.adv-card:hover .adv-icon {
  background: var(--gradient-primary);
  color: var(--white);
}
.adv-card h3 { font-size: 17px; margin-bottom: var(--sp-2); }
.adv-card p { font-size: 14px; color: var(--slate-500); line-height: 1.6; }

/* ─── Category Grid ─── */
.cat-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--sp-5);
}
.cat-card {
  position: relative;
  background: var(--white);
  border: 1px solid var(--slate-200);
  border-radius: var(--r-lg);
  padding: var(--sp-6);
  overflow: hidden;
  transition: all var(--t-slow);
  display: flex;
  align-items: center;
  gap: var(--sp-4);
}
.cat-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0;
  width: 4px; height: 100%;
  background: var(--gradient-primary);
  transform: scaleY(0);
  transform-origin: top;
  transition: transform var(--t-slow);
}
.cat-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
  border-color: transparent;
}
.cat-card:hover::before { transform: scaleY(1); }
.cat-icon {
  width: 48px; height: 48px;
  border-radius: var(--r-md);
  background: var(--slate-100);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent);
  flex-shrink: 0;
  transition: all var(--t-slow);
}
.cat-card:hover .cat-icon {
  background: var(--gradient-primary);
  color: var(--white);
}
.cat-info h4 { font-size: 15px; margin-bottom: 2px; }
.cat-info .count { font-size: 13px; color: var(--slate-400); }
.cat-arrow {
  margin-left: auto;
  color: var(--slate-300);
  transition: all var(--t-base);
}
.cat-card:hover .cat-arrow { color: var(--accent); transform: translateX(3px); }

/* ─── Product Cards ─── */
.prod-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--sp-5);
}
.prod-card {
  background: var(--white);
  border: 1px solid var(--slate-200);
  border-radius: var(--r-lg);
  overflow: hidden;
  transition: all var(--t-slow);
  display: flex;
  flex-direction: column;
}
.prod-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-4px);
  border-color: transparent;
}
.prod-img {
  aspect-ratio: 1;
  background: var(--slate-50);
  position: relative;
  overflow: hidden;
}
.prod-img img {
  width: 100%; height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}
.prod-card:hover .prod-img img { transform: scale(1.05); }
.prod-badge {
  position: absolute;
  top: 12px; left: 12px;
  background: var(--gradient-primary);
  color: white;
  font-size: 11px;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: var(--r-full);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.prod-body { padding: var(--sp-4) var(--sp-5) var(--sp-5); flex: 1; display: flex; flex-direction: column; }
.prod-name {
  font-size: 14px;
  font-weight: 600;
  color: var(--navy-800);
  line-height: 1.4;
  margin-bottom: var(--sp-2);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  min-height: 40px;
}
.prod-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: auto;
  padding-top: var(--sp-3);
}
.prod-moq {
  font-size: 12px;
  color: var(--slate-500);
  background: var(--slate-100);
  padding: 3px 10px;
  border-radius: var(--r-full);
}
.prod-link {
  font-size: 13px;
  font-weight: 600;
  color: var(--accent);
  display: inline-flex;
  align-items: center;
  gap: 4px;
  transition: gap var(--t-fast);
}
.prod-card:hover .prod-link { gap: 8px; }

/* ─── Stats ─── */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--sp-6);
  text-align: center;
}
.stat-item .num {
  font-size: 48px;
  font-weight: 800;
  letter-spacing: -0.03em;
  background: linear-gradient(135deg, #22D3EE, #60A5FA);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1.1;
}
.stat-item .lbl {
  font-size: 14px;
  color: var(--slate-400);
  margin-top: var(--sp-2);
}

/* ─── CTA Banner ─── */
.cta-banner {
  background: var(--gradient-hero);
  border-radius: var(--r-xl);
  padding: var(--sp-16) var(--sp-12);
  text-align: center;
  position: relative;
  overflow: hidden;
}
.cta-banner::before {
  content: '';
  position: absolute;
  top: -50%; right: -20%;
  width: 500px; height: 500px;
  background: radial-gradient(circle, rgba(6,182,212,0.12) 0%, transparent 70%);
  border-radius: 50%;
}
.cta-banner h2 { color: var(--white); position: relative; margin-bottom: var(--sp-3); }
.cta-banner p { color: rgba(255,255,255,0.65); font-size: 16px; margin-bottom: var(--sp-8); position: relative; }
.cta-banner .btn { position: relative; }

/* ─── Footer ─── */
.footer {
  background: var(--navy-900);
  color: var(--slate-400);
  padding: var(--sp-16) 0 var(--sp-8);
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1.5fr;
  gap: var(--sp-10);
  margin-bottom: var(--sp-12);
}
.footer-brand .nav-logo { color: var(--white); margin-bottom: var(--sp-4); }
.footer-brand p { font-size: 14px; line-height: 1.7; max-width: 320px; }
.footer h4 {
  color: var(--white);
  font-size: 14px;
  font-weight: 600;
  margin-bottom: var(--sp-4);
}
.footer ul li { margin-bottom: var(--sp-2); }
.footer ul a {
  font-size: 14px;
  color: var(--slate-400);
  transition: color var(--t-fast);
}
.footer ul a:hover { color: var(--cyan-400); }
.footer-contact li {
  font-size: 14px;
  display: flex;
  align-items: flex-start;
  gap: var(--sp-2);
  margin-bottom: var(--sp-3);
}
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.08);
  padding-top: var(--sp-6);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 13px;
}

/* ─── Forms ─── */
.form-group { margin-bottom: var(--sp-4); }
.form-label {
  display: block;
  font-size: 13px;
  font-weight: 600;
  color: var(--navy-700);
  margin-bottom: var(--sp-2);
}
.form-control {
  width: 100%;
  padding: 11px 16px;
  font-size: 14px;
  color: var(--navy-800);
  background: var(--white);
  border: 1.5px solid var(--slate-200);
  border-radius: var(--r-md);
  transition: all var(--t-fast);
  outline: none;
}
.form-control:focus {
  border-color: var(--accent);
  box-shadow: var(--shadow-glow);
}
.form-control::placeholder { color: var(--slate-400); }
textarea.form-control { resize: vertical; min-height: 100px; }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: var(--sp-4); }

/* ─── Breadcrumb ─── */
.breadcrumb {
  padding: var(--sp-4) 0;
  font-size: 13px;
  color: var(--slate-400);
}
.breadcrumb a:hover { color: var(--accent); }
.breadcrumb span { margin: 0 8px; }

/* ─── Badges ─── */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 3px 10px;
  font-size: 12px;
  font-weight: 600;
  border-radius: var(--r-full);
}
.badge-blue { background: var(--accent-light); color: var(--accent); }
.badge-green { background: #ECFDF5; color: #059669; }
.badge-amber { background: #FFFBEB; color: #D97706; }

/* ─── Utilities ─── */
.text-center { text-align: center; }
.mt-4 { margin-top: var(--sp-4); }
.mt-8 { margin-top: var(--sp-8); }
.mt-12 { margin-top: var(--sp-12); }
.mb-0 { margin-bottom: 0; }

/* ─── Animations ─── */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(24px); }
  to { opacity: 1; transform: translateY(0); }
}
.animate-in {
  opacity: 0;
  animation: fadeUp 0.7s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}
.animate-in:nth-child(2) { animation-delay: 0.1s; }
.animate-in:nth-child(3) { animation-delay: 0.2s; }
.animate-in:nth-child(4) { animation-delay: 0.3s; }

/* ─── Responsive ─── */
@media (max-width: 1024px) {
  .adv-grid, .cat-grid, .prod-grid, .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .hero-stats { gap: var(--sp-8); }
}

@media (max-width: 768px) {
  :root { --nav-h: 60px; }
  .nav-links { display: none; }
  .nav-toggle { display: flex; }
  .adv-grid, .cat-grid, .prod-grid, .stats-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: var(--sp-8); }
  .hero { padding: calc(var(--nav-h) + var(--sp-12)) 0 var(--sp-16); }
  .hero-stats { flex-wrap: wrap; gap: var(--sp-6); }
  .section { padding: var(--sp-16) 0; }
  .cta-banner { padding: var(--sp-10) var(--sp-6); }
  .form-row { grid-template-columns: 1fr; }
  .footer-bottom { flex-direction: column; gap: var(--sp-3); text-align: center; }
}