/* ===== Reset & Base ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: smooth; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
  color: #333; line-height: 1.6; background: #fff;
}

/* ===== Utility ===== */
.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }
.section-title {
  text-align: center; font-size: 1.75rem; font-weight: 700;
  color: #1a3a5c; margin-bottom: 0.5rem;
}
.section-title::after {
  content: ''; display: block; width: 60px; height: 4px;
  background: linear-gradient(90deg, #1a73e8, #4a9eff);
  margin: 12px auto 0; border-radius: 2px;
}
.section-subtitle { text-align: center; color: #666; font-size: 0.95rem; margin-bottom: 2.5rem; }
a { color: #1a73e8; text-decoration: none; transition: color 0.2s; }
a:hover { color: #1557b0; }
img { max-width: 100%; height: auto; }

/* ===== Top Bar ===== */
.top-bar {
  background: #1a3a5c; color: #ccc; font-size: 0.85rem; padding: 6px 0;
}
.top-bar .container { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 6px; }
.top-bar a { color: #fff; }
.top-bar a:hover { color: #4a9eff; }
.top-bar .hotline { color: #ffd700; font-weight: 600; font-size: 0.9rem; }

/* ===== Header ===== */
.site-header {
  background: #fff; border-bottom: 2px solid #f0f2f5; padding: 16px 0;
}
.site-header .container {
  display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 12px;
}
.logo-area { display: flex; align-items: center; gap: 16px; }
.logo-area img { height: 90px; width: auto; }
.logo-text h1 {
  font-size: 1.5rem; font-weight: 700; color: #1a3a5c; line-height: 1.2; margin: 0;
}
.logo-text span { font-size: 0.85rem; color: #888; display: block; margin-top: 2px; }
.header-contact { text-align: right; font-size: 0.9rem; }
.header-contact .phone { font-size: 1.4rem; font-weight: 700; color: #e63946; letter-spacing: 1px; }
.header-contact .phone-label { color: #666; font-size: 0.8rem; }

/* ===== Navigation ===== */
.main-nav {
  background: linear-gradient(90deg, #1a3a5c, #1a73e8);
  position: sticky; top: 0; z-index: 1000; box-shadow: 0 2px 8px rgba(0,0,0,0.12);
}
.main-nav .container { display: flex; align-items: stretch; flex-wrap: wrap; }
.main-nav a {
  color: #fff; padding: 14px 22px; font-size: 0.95rem;
  font-weight: 500; transition: background 0.2s; white-space: nowrap; display: block;
}
.main-nav a:hover, .main-nav a.active { background: rgba(255,255,255,0.15); }
.main-nav a.active { background: rgba(255,255,255,0.1); position: relative; }
.main-nav a.active::after {
  content: ''; position: absolute; bottom: 0; left: 20%; right: 20%;
  height: 3px; background: #ffd700; border-radius: 2px 2px 0 0;
}

/* ===== Page Layout ===== */
.page-wrapper { padding: 40px 0; background: #f8f9fb; min-height: 500px; }
.page-layout { display: flex; gap: 30px; align-items: flex-start; }

/* ===== Sidebar ===== */
.sidebar { flex: 0 0 260px; background: #fff; border-radius: 8px; border: 1px solid #eee; overflow: hidden; box-shadow: 0 2px 8px rgba(0,0,0,0.04); }
.sidebar-title {
  background: linear-gradient(90deg, #1a3a5c, #1a73e8); color: #fff;
  padding: 14px 18px; font-size: 1rem; font-weight: 600;
}
.sidebar ul { list-style: none; padding: 0; }
.sidebar ul li { border-bottom: 1px solid #f0f2f5; }
.sidebar ul li a {
  display: flex; align-items: center; gap: 8px;
  padding: 11px 16px; color: #444; font-size: 0.88rem; transition: all 0.2s;
}
.sidebar ul li a::before {
  content: ''; display: inline-block; width: 6px; height: 6px;
  border-top: 2px solid #1a73e8; border-right: 2px solid #1a73e8;
  transform: rotate(45deg); flex-shrink: 0;
}
.sidebar ul li a:hover { background: #f0f6ff; color: #1a73e8; padding-left: 20px; }
.sidebar ul li a.active { background: #e8f0fe; color: #1a73e8; font-weight: 600; }

/* ===== Main Content ===== */
.main-content {
  flex: 1; background: #fff; border-radius: 8px; border: 1px solid #eee;
  padding: 30px 35px; box-shadow: 0 2px 8px rgba(0,0,0,0.04); min-height: 400px;
}
.main-content h1 {
  font-size: 1.5rem; color: #1a3a5c; margin-bottom: 20px;
  padding-bottom: 12px; border-bottom: 2px solid #f0f2f5;
}
.main-content h2 { font-size: 1.2rem; color: #1a3a5c; margin: 24px 0 12px; }
.main-content h3 { font-size: 1.05rem; color: #1a73e8; margin: 18px 0 10px; }
.main-content p { margin-bottom: 12px; line-height: 1.8; font-size: 0.95rem; }
.main-content ul, .main-content ol { margin: 8px 0 16px 20px; }
.main-content li { margin-bottom: 6px; line-height: 1.7; font-size: 0.93rem; }
.main-content img { max-width: 100%; height: auto; border-radius: 4px; margin: 10px 0; }

/* ===== Product Grid ===== */
.product-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px;
}
.product-card {
  background: #fff; border-radius: 8px; overflow: hidden;
  box-shadow: 0 2px 12px rgba(0,0,0,0.08); transition: all 0.3s;
  border: 1px solid #eee;
}
.product-card:hover { transform: translateY(-4px); box-shadow: 0 8px 25px rgba(0,0,0,0.12); }
.product-card .card-img {
  width: 100%; height: 170px; overflow: hidden; display: flex;
  align-items: center; justify-content: center; background: #f5f7fa;
}
.product-card .card-img img { width: 100%; height: 100%; object-fit: cover; }
.product-card .card-body { padding: 14px 16px 16px; }
.product-card .card-body h3 { font-size: 0.95rem; font-weight: 600; color: #1a3a5c; margin-bottom: 4px; }
.product-card .card-body p { font-size: 0.8rem; color: #888; line-height: 1.4; margin: 0; }

/* ===== Contact Info ===== */
.contact-block { line-height: 2; font-size: 0.95rem; }
.contact-block dt { font-weight: 600; color: #1a3a5c; margin-top: 14px; }
.contact-block dt:first-child { margin-top: 0; }
.contact-block dd { margin-left: 0; color: #555; }
.contact-block .phone-big { color: #e63946; font-size: 1.3rem; font-weight: 700; }

/* ===== Footer ===== */
.site-footer { background: #0d2137; color: #aaa; font-size: 0.85rem; }
.site-footer .footer-main { padding: 40px 0; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 30px; }
.footer-grid h4 { color: #fff; font-size: 1rem; margin-bottom: 12px; }
.footer-grid ul { list-style: none; padding: 0; }
.footer-grid ul li { margin-bottom: 6px; }
.footer-grid ul li a { color: #999; font-size: 0.85rem; }
.footer-grid ul li a:hover { color: #4a9eff; }
.footer-brand p { line-height: 1.8; margin-bottom: 8px; color: #bbb; font-size: 0.85rem; }
.footer-brand .company-name { font-size: 1.1rem; font-weight: 700; color: #fff; margin-bottom: 10px; }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.08);
  padding: 14px 0; text-align: center; font-size: 0.8rem;
}
.footer-bottom a { color: #999; margin: 0 4px; }

/* ===== Nav Toggle ===== */
.nav-toggle {
  display: none; background: none; border: none; cursor: pointer; padding: 10px 14px;
}
.nav-toggle span {
  display: block; width: 24px; height: 3px; background: #fff;
  margin: 5px 0; border-radius: 2px; transition: 0.3s;
}

/* ===== Breadcrumb ===== */
.breadcrumb {
  font-size: 0.85rem; color: #999; margin-bottom: 16px; padding-bottom: 12px;
  border-bottom: 1px solid #f0f2f5;
}
.breadcrumb a { color: #1a73e8; }
.breadcrumb span { color: #333; }

/* ===== Spec Table ===== */
.spec-table { width: 100%; border-collapse: collapse; margin: 12px 0; font-size: 0.88rem; }
.spec-table th, .spec-table td {
  border: 1px solid #ddd; padding: 8px 12px; text-align: left;
}
.spec-table th { background: #f0f6ff; font-weight: 600; color: #1a3a5c; }

/* ===== Responsive ===== */
@media (max-width: 992px) {
  .product-grid { grid-template-columns: repeat(3, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .page-layout { flex-direction: column; }
  .sidebar { flex: 0 0 auto; width: 100%; }
}
@media (max-width: 768px) {
  .nav-toggle { display: block; }
  .main-nav .nav-links { display: none; width: 100%; flex-direction: column; background: #1a3a5c; }
  .main-nav .nav-links.open { display: flex; }
  .main-nav a { padding: 12px 20px; border-top: 1px solid rgba(255,255,255,0.06); }
  .main-nav a.active::after { display: none; }
  .product-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr; }
  .main-content { padding: 20px; }
  .logo-area img { height: 75px; }
  .logo-text h1 { font-size: 1.2rem; }
  .header-contact .phone { font-size: 1.1rem; }
  .top-bar .container { justify-content: center; text-align: center; }
}
@media (max-width: 480px) {
  .product-grid { grid-template-columns: repeat(2, 1fr); gap: 10px; }
  .product-card .card-img { height: 120px; }
  .product-card .card-body { padding: 10px; }
  .product-card .card-body h3 { font-size: 0.85rem; }
}

/* ===== Section Content (index page) ===== */
.section-content {
  padding: 60px 0;
}
.section-content:nth-child(even) {
  background: #f8f9fb;
}
.hero + .section-content {
  padding-top: 50px;
}