/* ========================================
   BeiDian Electric - Global Styles
   Industrial / Electrical B2B Website
   ======================================== */

:root {
  --navy-900: #0a1628;
  --navy-800: #0f1f35;
  --navy-700: #162a47;
  --navy-600: #1e3a5f;
  --navy-500: #2a4a73;
  --amber-500: #d4942a;
  --amber-400: #e8a93d;
  --amber-300: #f2c060;
  --amber-600: #b87d1e;
  --electric-500: #2e7fe8;
  --electric-400: #4a95f5;
  --electric-300: #6db0ff;
  --steel-100: #f5f6f8;
  --steel-200: #e8eaee;
  --steel-300: #d1d5dc;
  --steel-400: #a8b0bd;
  --steel-500: #7a8496;
  --steel-600: #555e6e;
  --steel-700: #3b4250;
  --steel-800: #252a34;
  --steel-900: #141820;
  --font-display: 'Oswald', sans-serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', monospace;
  --section-py: 100px;
  --container: 1280px;
  --shadow-sm: 0 1px 2px rgba(10, 22, 40, 0.06), 0 1px 3px rgba(10, 22, 40, 0.08);
  --shadow-md: 0 4px 6px rgba(10, 22, 40, 0.07), 0 10px 20px rgba(10, 22, 40, 0.08);
  --shadow-lg: 0 10px 25px rgba(10, 22, 40, 0.1), 0 20px 50px rgba(10, 22, 40, 0.12);
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-body);
  color: var(--steel-800);
  background: var(--steel-100);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
a { color: inherit; text-decoration: none; }
button { font-family: inherit; cursor: pointer; border: none; background: none; }
img { max-width: 100%; display: block; }
ul { list-style: none; }

.container { max-width: var(--container); margin: 0 auto; padding: 0 32px; }
.section { padding: var(--section-py) 0; }
.section-header { text-align: center; margin-bottom: 64px; }
.section-label {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--amber-500);
  margin-bottom: 12px;
  display: inline-flex;
  align-items: center;
  gap: 12px;
}
.section-label::before, .section-label::after {
  content: ''; width: 24px; height: 1px; background: var(--amber-500);
}
.section-title {
  font-family: var(--font-display);
  font-size: 44px;
  font-weight: 600;
  line-height: 1.15;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  color: var(--navy-900);
  margin-bottom: 16px;
}
.section-subtitle {
  font-size: 17px;
  color: var(--steel-600);
  max-width: 640px;
  margin: 0 auto;
  line-height: 1.7;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 14px 32px;
  font-family: var(--font-display);
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  border: 2px solid transparent;
  transition: all 0.25s ease;
  position: relative;
  overflow: hidden;
}
.btn-primary { background: var(--amber-500); color: var(--navy-900); border-color: var(--amber-500); }
.btn-primary:hover {
  background: var(--amber-400); border-color: var(--amber-400);
  transform: translateY(-1px); box-shadow: 0 6px 20px rgba(212, 148, 42, 0.35);
}
.btn-outline { background: transparent; color: #fff; border-color: rgba(255, 255, 255, 0.5); }
.btn-outline:hover { background: rgba(255, 255, 255, 0.1); border-color: #fff; }
.btn-outline-navy { background: transparent; color: var(--navy-800); border-color: var(--navy-800); }
.btn-outline-navy:hover { background: var(--navy-800); color: #fff; }

.site-header {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  background: rgba(10, 22, 40, 0.95);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
  transition: all 0.3s ease;
}
.site-header.scrolled { background: rgba(10, 22, 40, 0.98); box-shadow: 0 2px 20px rgba(0, 0, 0, 0.2); }
.header-inner {
  max-width: var(--container); margin: 0 auto; padding: 0 32px;
  display: flex; align-items: center; justify-content: space-between; height: 80px;
}
.logo { display: flex; align-items: center; gap: 12px; cursor: pointer; }
.logo-mark {
  width: 44px; height: 44px; background: var(--amber-500);
  display: flex; align-items: center; justify-content: center; position: relative;
}
.logo-mark::before {
  content: ''; position: absolute; top: 3px; left: 3px; right: 3px; bottom: 3px;
  border: 1.5px solid var(--navy-900);
}
.logo-mark-text {
  font-family: var(--font-display); font-size: 18px; font-weight: 700;
  color: var(--navy-900); letter-spacing: 0.5px;
}
.logo-text { display: flex; flex-direction: column; line-height: 1.1; }
.logo-brand {
  font-family: var(--font-display); font-size: 20px; font-weight: 600;
  letter-spacing: 1px; color: #fff; text-transform: uppercase;
}
.logo-sub {
  font-family: var(--font-mono); font-size: 10px; letter-spacing: 2px;
  color: var(--steel-400); text-transform: uppercase; margin-top: 2px;
}
.main-nav { display: flex; align-items: center; gap: 8px; }
.nav-link {
  font-family: var(--font-display); font-size: 14px; font-weight: 500;
  letter-spacing: 1.2px; text-transform: uppercase; color: var(--steel-300);
  padding: 10px 16px; position: relative; transition: color 0.2s ease;
}
.nav-link:hover { color: #fff; }
.nav-link.active { color: var(--amber-500); }
.nav-link.active::after {
  content: ''; position: absolute; bottom: -2px; left: 16px; right: 16px;
  height: 2px; background: var(--amber-500);
}
.header-cta { display: flex; align-items: center; gap: 16px; }
.header-phone { display: flex; align-items: center; gap: 8px; color: var(--steel-300); font-size: 14px; }
.header-phone strong { color: #fff; font-weight: 600; font-family: var(--font-mono); }
.hamburger { display: none; flex-direction: column; gap: 5px; padding: 8px; cursor: pointer; }
.hamburger span { display: block; width: 24px; height: 2px; background: #fff; transition: all 0.3s ease; }
.mobile-nav {
  display: none; position: fixed; top: 80px; left: 0; right: 0;
  background: var(--navy-900); padding: 20px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1); z-index: 999;
}
.mobile-nav.open { display: block; }
.mobile-nav-link {
  display: block; padding: 14px 0; font-family: var(--font-display);
  font-size: 16px; font-weight: 500; letter-spacing: 1px; text-transform: uppercase;
  color: var(--steel-300); border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}
.mobile-nav-link:last-child { border-bottom: none; }
.mobile-nav-link.active { color: var(--amber-500); }

.page { animation: fadeIn 0.4s ease; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }

.site-footer { background: var(--navy-900); color: var(--steel-400); padding-top: 80px; }
.footer-grid {
  display: grid; grid-template-columns: 1.5fr 1fr 1fr 1.3fr;
  gap: 48px; padding-bottom: 60px; border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}
.footer-col h4 {
  font-family: var(--font-display); font-size: 16px; font-weight: 600;
  letter-spacing: 1.5px; text-transform: uppercase; color: #fff;
  margin-bottom: 24px; position: relative; padding-bottom: 12px;
}
.footer-col h4::after {
  content: ''; position: absolute; bottom: 0; left: 0; width: 32px; height: 2px; background: var(--amber-500);
}
.footer-col p { font-size: 14px; line-height: 1.7; margin-bottom: 16px; }
.footer-col ul li { margin-bottom: 12px; }
.footer-col ul li a {
  font-size: 14px; color: var(--steel-400); transition: color 0.2s ease;
  display: inline-flex; align-items: center; gap: 8px;
}
.footer-col ul li a:hover { color: var(--amber-500); }
.footer-col ul li a::before { content: '›'; color: var(--amber-500); font-weight: 600; }
.footer-about p { margin-top: 20px; }
.footer-contact li {
  display: flex; align-items: flex-start; gap: 10px; font-size: 14px;
  line-height: 1.6; margin-bottom: 14px;
}
.footer-contact-icon { color: var(--amber-500); font-size: 14px; margin-top: 3px; flex-shrink: 0; }
.footer-bottom {
  padding: 24px 0; display: flex; justify-content: space-between; align-items: center;
  font-size: 13px; color: var(--steel-500);
}
.footer-bottom-links { display: flex; gap: 24px; }
.footer-bottom-links a:hover { color: var(--amber-500); }

.card-lift { transition: transform 0.3s ease, box-shadow 0.3s ease; }
.card-lift:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); }

.text-center { text-align: center; }
.text-amber { color: var(--amber-500); }
.text-navy { color: var(--navy-900); }
.bg-navy { background: var(--navy-900); }
.bg-steel { background: var(--steel-100); }
.bg-white { background: #fff; }

.page-header {
  position: relative; padding: 160px 0 100px; background: var(--navy-900); overflow: hidden;
}
.page-header-bg {
  position: absolute; inset: 0;
  background: radial-gradient(ellipse at 20% 50%, rgba(212, 148, 42, 0.1), transparent 60%),
    linear-gradient(135deg, var(--navy-900), var(--navy-700));
}
.page-header-bg::before {
  content: ''; position: absolute; inset: 0;
  background-image: linear-gradient(rgba(255, 255, 255, 0.02) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.02) 1px, transparent 1px);
  background-size: 40px 40px;
}
.page-header-content {
  position: relative; z-index: 2; text-align: center; color: #fff;
  max-width: 800px; margin: 0 auto;
}
.page-header-content h1 {
  font-family: var(--font-display); font-size: 56px; font-weight: 600;
  letter-spacing: 1px; text-transform: uppercase; margin-bottom: 20px; line-height: 1.1;
}
.page-header-content p { font-size: 17px; color: var(--steel-300); line-height: 1.7; }
.page-header-content .section-label { margin-bottom: 20px; }

.product-filter-section {
  background: #fff; border-bottom: 1px solid var(--steel-200);
  position: sticky; top: 80px; z-index: 100; box-shadow: 0 2px 10px rgba(0,0,0,0.04);
}
.product-filter { display: flex; gap: 4px; padding: 16px 0; flex-wrap: wrap; }
.filter-btn {
  font-family: var(--font-display); font-size: 13px; font-weight: 500;
  letter-spacing: 1px; text-transform: uppercase; padding: 10px 24px;
  color: var(--steel-600); border: 1px solid transparent; transition: all 0.2s ease; background: transparent;
}
.filter-btn:hover { color: var(--navy-900); }
.filter-btn.active { color: var(--navy-900); background: var(--steel-100); border-color: var(--steel-300); }

@media (max-width: 1024px) {
  .footer-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 768px) {
  :root { --section-py: 60px; }
  .container { padding: 0 20px; }
  .header-inner { height: 64px; padding: 0 20px; }
  .main-nav, .header-phone { display: none; }
  .hamburger { display: flex; }
  .logo-brand { font-size: 17px; }
  .logo-sub { font-size: 9px; }
  .section-title { font-size: 30px; }
  .section-subtitle { font-size: 15px; }
  .section-header { margin-bottom: 40px; }
  .footer-grid { grid-template-columns: 1fr; gap: 36px; padding-bottom: 40px; }
  .footer-bottom { flex-direction: column; gap: 12px; text-align: center; }
  .page-header { padding: 120px 0 60px; }
  .page-header-content h1 { font-size: 32px; }
  .page-header-content p { font-size: 15px; }
  .product-filter-section { top: 64px; }
}

/* Social Icons */
.social-icon {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  border: 1px solid rgba(255, 255, 255, 0.2);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--steel-400);
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  text-decoration: none;
  background: rgba(255, 255, 255, 0.03);
}

.social-icon:hover {
  transform: translateY(-3px);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.3);
}

.social-icon[title="Facebook"]:hover {
  background: #1877F2;
  border-color: #1877F2;
  color: #fff;
}

.social-icon[title="LinkedIn"]:hover {
  background: #0A66C2;
  border-color: #0A66C2;
  color: #fff;
}

.social-icon[title="WhatsApp"]:hover {
  background: #25D366;
  border-color: #25D366;
  color: #fff;
}