/* === CSS Variables === */
:root {
  --primary: #1e40af;
  --primary-light: #dbeafe;
  --primary-dark: #1e3a8a;
  --accent: #059669;
  --accent-light: #d1fae5;
  --ink: #1e293b;
  --muted: #64748b;
  --bg: #f8fafc;
  --white: #ffffff;
  --border: #e2e8f0;
  --danger: #dc2626;
  --warning: #d97706;
  --radius: 8px;
  --radius-lg: 14px;
  --shadow: 0 4px 24px rgba(0,0,0,0.08);
  --shadow-lg: 0 12px 40px rgba(0,0,0,0.12);
  --font: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --max-width: 1140px;
}

/* === Reset === */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: var(--font); color: var(--ink); background: var(--bg); line-height: 1.7; font-size: 16px; }
a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }
img { max-width: 100%; display: block; }

/* === Layout Utilities === */
.container { max-width: var(--max-width); margin: 0 auto; padding: 0 24px; }
.section { padding: 80px 0; }
.section-sm { padding: 48px 0; }

/* === Button System === */
.btn {
  display: inline-block; padding: 14px 32px; border-radius: var(--radius);
  font-size: 16px; font-weight: 600; cursor: pointer; border: none;
  transition: all 0.2s; text-align: center; text-decoration: none;
}
.btn:hover { text-decoration: none; }
.btn-primary { background: var(--primary); color: var(--white); }
.btn-primary:hover { background: var(--primary-dark); transform: translateY(-1px); }
.btn-secondary { background: var(--white); color: var(--primary); border: 2px solid var(--primary); }
.btn-secondary:hover { background: var(--primary-light); }
.btn-accent { background: #047857; color: var(--white); }
.btn-accent:hover { background: #047857; transform: translateY(-1px); }
.btn-lg { padding: 18px 40px; font-size: 18px; }

/* === Nav === */
.nav { background: var(--white); border-bottom: 1px solid var(--border); position: sticky; top: 0; z-index: 100; }
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 64px; max-width: var(--max-width); margin: 0 auto; padding: 0 24px; }
.nav-logo { font-size: 20px; font-weight: 700; color: var(--primary); }
.nav-links { display: flex; gap: 32px; list-style: none; align-items: center; }
.nav-links a { color: var(--ink); font-weight: 500; }
.nav-links a:hover { color: var(--primary); text-decoration: none; }
.lang-switch { background: var(--bg); border: 1px solid var(--border); padding: 6px 14px; border-radius: var(--radius); font-size: 14px; cursor: pointer; }
.mobile-menu-btn { display: none; background: none; border: none; font-size: 24px; cursor: pointer; }

/* === Mobile === */
@media (max-width: 768px) {
  .nav-links { display: none; position: absolute; top: 64px; left: 0; right: 0; background: var(--white); flex-direction: column; padding: 24px; border-bottom: 1px solid var(--border); gap: 16px; }
  .nav-links.open { display: flex; }
  .mobile-menu-btn { display: block; }
  .section { padding: 48px 0; }
}

/* === Product Gallery Cards === */
.product-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 300px), 1fr)); gap: 28px; }
.product-card { background: var(--white); border-radius: var(--radius-lg); overflow: hidden; box-shadow: var(--shadow); transition: transform 0.2s, box-shadow 0.2s; }
.product-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); }
.product-card img { width: 100%; height: 230px; object-fit: cover; object-position: center; background: var(--bg); }
.product-info { padding: 20px 24px 24px; }
.product-tag { display: inline-block; background: var(--primary); color: var(--white); font-size: 12px; font-weight: 700; padding: 3px 12px; border-radius: 100px; margin-bottom: 10px; letter-spacing: 0.5px; }
.product-info h3 { font-size: 19px; margin-bottom: 4px; }
.product-use { color: var(--muted); font-size: 14px; margin-bottom: 14px; }
.spec-chips { display: flex; flex-wrap: wrap; gap: 6px; }
.spec-chips span { background: var(--bg); border: 1px solid var(--border); font-size: 12px; padding: 3px 10px; border-radius: 100px; font-weight: 600; }

/* === Stats Bar === */
.stats-bar { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 150px), 1fr)); gap: 16px; text-align: center; }
.stat-item { padding: 8px 4px; }
.stat-num { font-size: 30px; font-weight: 800; color: var(--primary); line-height: 1.2; }
.stat-label { font-size: 13px; color: var(--muted); margin-top: 2px; }

/* === Brand Wall === */
.brand-wall { display: flex; flex-wrap: wrap; gap: 14px 34px; justify-content: center; align-items: center; }
.brand-wall span { font-size: 19px; font-weight: 700; color: var(--muted); letter-spacing: 0.5px; }

/* === Core Components === */
.parts-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 200px), 1fr)); gap: 16px; }
.part-card { background: var(--white); border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow); }
.part-card img { width: 100%; height: 150px; object-fit: cover; }
.part-card p { padding: 10px 14px; font-size: 13px; font-weight: 600; text-align: center; }
.figure-caption { font-size: 13px; color: var(--muted); text-align: center; margin-top: 8px; }

/* === Mobile refinements === */
@media (max-width: 768px) {
  .stat-num { font-size: 24px; }
  .stats-bar { grid-template-columns: repeat(2, 1fr); gap: 10px; }
  .brand-wall span { font-size: 15px; }
  .product-card img { height: 190px; }
  select.lang-switch { font-size: 13px; padding: 5px 8px; }
  .part-card img { height: 130px; }
  .section { padding: 44px 0; }
}
@media (max-width: 420px) {
  .stats-bar { grid-template-columns: repeat(2, 1fr); }
  .stat-num { font-size: 21px; }
  .stat-label { font-size: 11px; }
  .btn { padding: 12px 22px; font-size: 15px; }
  .btn-lg { padding: 15px 26px; font-size: 16px; }
}

/* === Doc-pack responsive === */
@media (max-width: 640px) {
  .doc-pack { grid-template-columns: 1fr !important; }
  .doc-pack .btn { white-space: normal !important; }
}