/* ===== 北岛电气 BeiDao Electric - 官网样式表 v2 ===== */
:root {
  --primary: #152e47;
  --primary-light: #1e4265;
  --primary-dark: #0b1d30;
  --accent: #d4342e;
  --accent-hover: #b8201b;
  --accent-light: #fef2f2;
  --gold: #d4a017;
  --text: #2d3748;
  --text-mid: #4a5568;
  --text-light: #718096;
  --bg: #f5f6f8;
  --bg-white: #ffffff;
  --border: #e2e8f0;
  --border-light: #edf2f7;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow: 0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08), 0 2px 4px rgba(0,0,0,0.04);
  --shadow-lg: 0 12px 32px rgba(0,0,0,0.12), 0 4px 8px rgba(0,0,0,0.06);
  --shadow-xl: 0 20px 48px rgba(0,0,0,0.15);
  --radius: 10px;
  --radius-sm: 6px;
  --radius-lg: 16px;
  --max-width: 1200px;
  --header-height: 72px;
  --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.72;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a { text-decoration: none; color: inherit; }
ul { list-style: none; }
img { max-width: 100%; height: auto; display: block; }

/* ===== Header ===== */
.header {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  background: rgba(255,255,255,0.95);
  backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  height: var(--header-height);
  transition: box-shadow var(--transition);
}
.header.scrolled { box-shadow: var(--shadow-md); }

.header-inner {
  max-width: var(--max-width); margin: 0 auto;
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 28px; height: 100%;
}

.logo { display: flex; align-items: center; gap: 10px; flex-shrink: 0; }
.logo img { height: 40px; }
.logo-text {
  font-size: 20px; font-weight: 800; color: var(--primary);
  letter-spacing: 0.5px; white-space: nowrap;
}
.logo-text span { color: var(--accent); }

.nav { display: flex; gap: 2px; }
.nav > li { position: relative; }
.nav > li > a {
  display: block; padding: 8px 15px; font-size: 14.5px; font-weight: 500;
  color: var(--text-mid); border-radius: var(--radius-sm);
  transition: all var(--transition); position: relative;
}
.nav > li > a::after {
  content: ''; position: absolute; bottom: 4px; left: 50%; transform: translateX(-50%);
  width: 0; height: 2px; background: var(--accent); border-radius: 1px;
  transition: width var(--transition);
}
.nav > li > a:hover { color: var(--accent); }
.nav > li > a:hover::after { width: 60%; }

.nav .dropdown {
  display: none; position: absolute; top: calc(100% + 4px); left: 0;
  background: var(--bg-white); border: 1px solid var(--border);
  border-radius: var(--radius); box-shadow: var(--shadow-lg);
  min-width: 190px; padding: 8px 0; animation: fadeDown 0.2s ease;
}
@keyframes fadeDown { from { opacity:0; transform:translateY(-8px); } to { opacity:1; transform:translateY(0); } }
.nav li:hover .dropdown { display: block; }
.nav .dropdown a {
  display: block; padding: 9px 20px; font-size: 13.5px; color: var(--text-mid);
  transition: all 0.15s;
}
.nav .dropdown a:hover { color: var(--accent); background: var(--accent-light); }

.header-cta { display: flex; align-items: center; gap: 14px; flex-shrink: 0; }
.header-phone { font-size: 12px; color: var(--text-light); text-align: right; line-height: 1.3; }
.header-phone strong { font-size: 18px; color: var(--accent); display: block; font-weight: 700; }

.btn {
  display: inline-flex; align-items: center; gap: 6px; padding: 11px 24px;
  font-size: 14px; font-weight: 600; border-radius: var(--radius-sm);
  cursor: pointer; transition: all var(--transition); border: none;
  white-space: nowrap; letter-spacing: 0.3px;
}
.btn-primary { background: var(--accent); color: #fff; box-shadow: 0 2px 8px rgba(212,52,46,0.3); }
.btn-primary:hover { background: var(--accent-hover); transform: translateY(-2px); box-shadow: 0 6px 16px rgba(212,52,46,0.4); }
.btn-outline { border: 2px solid var(--primary); color: var(--primary); background: transparent; }
.btn-outline:hover { background: var(--primary); color: #fff; transform: translateY(-1px); }
.btn-white { background: #fff; color: var(--primary); box-shadow: var(--shadow-md); }
.btn-white:hover { background: transparent; color: #fff; box-shadow: none; }

.menu-toggle { display: none; flex-direction: column; gap: 5px; cursor: pointer; padding: 8px; z-index: 1001; }
.menu-toggle span { width: 24px; height: 2.5px; background: var(--primary); border-radius: 2px; transition: all 0.3s; }

/* ===== Hero ===== */
.hero {
  margin-top: var(--header-height);
  background: linear-gradient(160deg, #0b1d30 0%, #152e47 35%, #1a3c5e 60%, #1e4d78 100%);
  color: #fff; padding: 90px 24px 110px; text-align: center;
  position: relative; overflow: hidden;
}
.hero::before {
  content: ''; position: absolute; top: -50%; right: -20%; width: 600px; height: 600px;
  background: radial-gradient(circle, rgba(212,52,46,0.12) 0%, transparent 70%);
  border-radius: 50%;
}
.hero::after {
  content: ''; position: absolute; bottom: -30%; left: -10%; width: 500px; height: 500px;
  background: radial-gradient(circle, rgba(212,160,23,0.08) 0%, transparent 70%);
  border-radius: 50%;
}

.hero-inner { max-width: 820px; margin: 0 auto; position: relative; z-index: 1; }
.hero-badge {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 7px 18px; background: rgba(255,255,255,0.12);
  border: 1px solid rgba(255,255,255,0.2); border-radius: 50px;
  font-size: 13px; margin-bottom: 28px; letter-spacing: 0.5px;
}
.hero h1 { font-size: 44px; font-weight: 800; line-height: 1.3; margin-bottom: 18px; letter-spacing: 1px; }
.hero h1 em { font-style: normal; color: #fbbf24; position: relative; }
.hero h1 em::after {
  content: ''; position: absolute; bottom: 2px; left: 0; right: 0; height: 3px;
  background: rgba(251,191,36,0.3); border-radius: 2px;
}
.hero p { font-size: 17px; color: rgba(255,255,255,0.78); margin-bottom: 36px; max-width: 620px; margin-left: auto; margin-right: auto; line-height: 1.8; }
.hero-btns { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }
.hero-btns .btn { padding: 13px 32px; font-size: 15px; }
.hero-stats { display: flex; gap: 48px; justify-content: center; margin-top: 56px; flex-wrap: wrap; }
.hero-stat { text-align: center; }
.hero-stat-num { font-size: 34px; font-weight: 800; color: #fbbf24; letter-spacing: 0.5px; }
.hero-stat-label { font-size: 13px; color: rgba(255,255,255,0.6); margin-top: 6px; }

/* ===== Section Common ===== */
.section { padding: 80px 24px; }
.section-alt { background: var(--bg-white); }
.section-inner { max-width: var(--max-width); margin: 0 auto; }
.section-title { text-align: center; margin-bottom: 52px; }
.section-title h2 { font-size: 30px; font-weight: 700; color: var(--primary); margin-bottom: 12px; letter-spacing: 0.5px; }
.section-title p { font-size: 15px; color: var(--text-light); max-width: 600px; margin: 0 auto; }
.section-title .divider {
  width: 50px; height: 3px;
  background: linear-gradient(90deg, var(--accent), #f87171);
  margin: 14px auto; border-radius: 2px;
}

/* ===== Products Grid ===== */
.products-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(350px, 1fr)); gap: 28px; }
.product-card {
  background: var(--bg-white); border-radius: var(--radius-lg); overflow: hidden;
  box-shadow: var(--shadow); transition: all var(--transition);
  border: 1px solid var(--border-light); display: block;
}
.product-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-xl);
  border-color: #cbd5e0;
}
.product-card-img {
  height: 220px; position: relative; overflow: hidden;
  background: linear-gradient(135deg, #e8ecf1 0%, #dce3ea 100%);
}
.product-card-img img { width: 100%; height: 100%; object-fit: cover; transition: transform 0.5s ease; }
.product-card:hover .product-card-img img { transform: scale(1.06); }
.product-card-img .img-icon {
  font-size: 52px; opacity: 0.25; position: absolute;
  top: 50%; left: 50%; transform: translate(-50%,-50%);
}
.product-card-img::after {
  content: ''; position: absolute; bottom: 0; left: 0; right: 0;
  height: 40px; background: linear-gradient(transparent, rgba(0,0,0,0.03));
}
.product-card-body { padding: 22px 24px; }
.product-card-body h3 { font-size: 18px; font-weight: 700; color: var(--primary); margin-bottom: 10px; }
.product-card-body p { font-size: 14px; color: var(--text-light); line-height: 1.65; margin-bottom: 14px; }
.product-card-tags { display: flex; flex-wrap: wrap; gap: 6px; }
.product-card-tags span {
  padding: 5px 12px; background: #f1f5f9; border-radius: 50px;
  font-size: 11.5px; color: var(--text-light); font-weight: 500;
  transition: all var(--transition);
}
.product-card:hover .product-card-tags span { background: #e8eff6; }

/* Product card colored accents */
.product-card-accent { height: 3px; }
.accent-red { background: var(--accent); }
.accent-blue { background: #3b82f6; }
.accent-green { background: #10b981; }
.accent-purple { background: #8b5cf6; }
.accent-orange { background: #f59e0b; }

/* ===== Cases Grid ===== */
.cases-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.case-card {
  position: relative; border-radius: var(--radius); overflow: hidden;
  box-shadow: var(--shadow); cursor: pointer; aspect-ratio: 4/3;
  display: block;
}
.case-card img { width: 100%; height: 100%; object-fit: cover; transition: transform 0.5s ease; }
.case-card:hover img { transform: scale(1.08); }
.case-card-overlay {
  position: absolute; bottom: 0; left: 0; right: 0;
  background: linear-gradient(transparent 0%, rgba(0,0,0,0.25) 30%, rgba(0,0,0,0.82) 100%);
  padding: 48px 20px 18px; color: #fff;
}
.case-card-overlay h4 { font-size: 16px; font-weight: 700; margin-bottom: 4px; }
.case-card-overlay span { font-size: 12px; opacity: 0.82; }
.case-tags { display: flex; gap: 10px; justify-content: center; margin-bottom: 36px; flex-wrap: wrap; }
.case-tag {
  padding: 9px 22px; border-radius: 50px; font-size: 14px; font-weight: 500;
  cursor: pointer; transition: all var(--transition);
  border: 1.5px solid var(--border); background: var(--bg-white); color: var(--text-mid);
}
.case-tag.active, .case-tag:hover {
  background: var(--primary); color: #fff; border-color: var(--primary);
  box-shadow: 0 4px 12px rgba(21,46,71,0.3);
}

/* ===== Advantages ===== */
.adv-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
.adv-card {
  text-align: center; padding: 36px 22px; border-radius: var(--radius-lg);
  transition: all var(--transition); border: 1px solid transparent;
  background: var(--bg-white);
}
.adv-card:hover {
  box-shadow: var(--shadow-lg); border-color: var(--border);
  transform: translateY(-3px);
}
.adv-icon {
  width: 68px; height: 68px; margin: 0 auto 18px;
  background: linear-gradient(135deg, #fef2f2 0%, #fee2e2 100%);
  border-radius: 18px; display: flex; align-items: center; justify-content: center;
  font-size: 30px; transition: all var(--transition);
}
.adv-card:hover .adv-icon { transform: scale(1.1); }
.adv-card h4 { font-size: 17px; font-weight: 700; color: var(--primary); margin-bottom: 10px; }
.adv-card p { font-size: 13.5px; color: var(--text-light); line-height: 1.7; }

/* ===== CTA Banner ===== */
.cta-banner {
  background: linear-gradient(150deg, #d4342e 0%, #c02626 40%, #a01020 100%);
  color: #fff; text-align: center; padding: 72px 24px;
  position: relative; overflow: hidden;
}
.cta-banner::before {
  content: ''; position: absolute; top: -30%; right: -15%; width: 400px; height: 400px;
  background: radial-gradient(circle, rgba(255,255,255,0.08) 0%, transparent 70%);
  border-radius: 50%;
}
.cta-banner-inner { position: relative; z-index: 1; }
.cta-banner h2 { font-size: 30px; margin-bottom: 12px; font-weight: 700; }
.cta-banner p { font-size: 16px; opacity: 0.88; margin-bottom: 28px; }
.cta-banner .btn-white { font-size: 16px; padding: 14px 40px; }

/* ===== News ===== */
.news-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 28px; }
.news-card {
  background: var(--bg-white); border-radius: var(--radius-lg); overflow: hidden;
  box-shadow: var(--shadow); transition: all var(--transition);
}
.news-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); }
.news-card-img { height: 190px; background: #e8ecf1; overflow: hidden; }
.news-card-img img { width: 100%; height: 100%; object-fit: cover; transition: transform 0.4s; }
.news-card:hover .news-card-img img { transform: scale(1.04); }
.news-card-body { padding: 22px 20px; }
.news-card-body h4 { font-size: 16px; font-weight: 600; margin-bottom: 8px; line-height: 1.5; color: var(--primary); }
.news-card-body h4 a:hover { color: var(--accent); }
.news-card-body time { font-size: 12px; color: var(--text-light); }
.news-card-body p { font-size: 13.5px; color: var(--text-light); margin-top: 10px; line-height: 1.7; }

/* ===== Footer ===== */
.footer {
  background: linear-gradient(180deg, #0f263e 0%, #0b1d30 100%);
  color: rgba(255,255,255,0.65); padding: 56px 24px 28px;
}
.footer-inner {
  max-width: var(--max-width); margin: 0 auto;
  display: grid; grid-template-columns: 2fr 1fr 1fr 1.5fr; gap: 44px;
}
.footer h4 { color: #fff; font-size: 16px; margin-bottom: 18px; font-weight: 600; letter-spacing: 0.3px; }
.footer a { color: rgba(255,255,255,0.55); font-size: 13.5px; transition: color 0.2s; display: block; padding: 4px 0; }
.footer a:hover { color: #fff; }
.footer-brand p { font-size: 13px; margin-top: 14px; line-height: 1.9; }
.footer-contact p { font-size: 13px; margin-bottom: 7px; }
.footer-contact strong { color: #fbbf24; font-size: 19px; font-weight: 700; }
.footer-bottom {
  max-width: var(--max-width); margin: 36px auto 0; padding-top: 22px;
  border-top: 1px solid rgba(255,255,255,0.08); text-align: center; font-size: 12px;
  color: rgba(255,255,255,0.35);
}

/* ===== Page Header ===== */
.page-header {
  margin-top: var(--header-height);
  background: linear-gradient(135deg, var(--primary-dark) 0%, var(--primary) 50%, var(--primary-light) 100%);
  color: #fff; padding: 56px 24px 52px; text-align: center;
  position: relative; overflow: hidden;
}
.page-header::after {
  content: ''; position: absolute; bottom: 0; left: 0; right: 0; height: 3px;
  background: linear-gradient(90deg, transparent, var(--accent), transparent);
}
.page-header h1 { font-size: 32px; font-weight: 700; letter-spacing: 1px; position: relative; z-index: 1; }
.page-header .breadcrumb {
  font-size: 13px; opacity: 0.65; margin-top: 10px; position: relative; z-index: 1;
}
.page-header .breadcrumb a { color: rgba(255,255,255,0.75); }
.page-header .breadcrumb a:hover { color: #fff; text-decoration: underline; }

/* ===== About Page ===== */
.about-section { padding: 64px 24px; background: var(--bg-white); }
.about-content { max-width: 860px; margin: 0 auto; }
.about-content h3 {
  font-size: 21px; color: var(--primary); margin: 36px 0 18px;
  padding-left: 14px; border-left: 3px solid var(--accent); font-weight: 700;
}
.about-content p { font-size: 15px; line-height: 1.95; color: var(--text); margin-bottom: 18px; }
.about-content .highlight {
  background: linear-gradient(135deg, #fffbeb, #fef3c7);
  border: 1px solid #fcd34d; border-radius: var(--radius);
  padding: 22px 28px; margin: 28px 0; font-size: 15px; line-height: 1.9;
}

/* ===== Contact Page ===== */
.contact-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 44px; align-items: start; }
.contact-info h3 { font-size: 20px; color: var(--primary); margin-bottom: 20px; font-weight: 700; }
.contact-info-item { display: flex; gap: 14px; margin-bottom: 22px; align-items: flex-start; }
.contact-info-item .icon {
  width: 44px; height: 44px; background: linear-gradient(135deg, var(--accent), #e85050);
  border-radius: 12px; display: flex; align-items: center; justify-content: center;
  color: #fff; font-size: 18px; flex-shrink: 0; box-shadow: 0 4px 12px rgba(212,52,46,0.25);
}
.contact-info-item strong { display: block; font-size: 14px; margin-bottom: 3px; color: var(--text); }
.contact-info-item span { font-size: 14px; color: var(--text-light); }
.contact-map {
  border-radius: var(--radius-lg); overflow: hidden; height: 420px;
  background: linear-gradient(135deg, #e8ecf1, #dce3ea);
  box-shadow: var(--shadow-md);
}

/* ===== Decorative section divider ===== */
.section-divider {
  height: 80px; background: linear-gradient(180deg, var(--bg) 0%, var(--bg-white) 100%);
}

/* ===== Image fallback styling ===== */
.img-fallback {
  display: flex; align-items: center; justify-content: center;
  font-size: 48px; color: rgba(0,0,0,0.08);
}

/* ===== Animations ===== */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(24px); }
  to { opacity: 1; transform: translateY(0); }
}
.animate-in {
  animation: fadeInUp 0.6s ease forwards;
}

/* ===== Responsive ===== */
@media (max-width: 1024px) {
  .products-grid { grid-template-columns: repeat(2, 1fr); }
  .cases-grid { grid-template-columns: repeat(2, 1fr); }
  .news-grid { grid-template-columns: repeat(2, 1fr); }
  .adv-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-inner { grid-template-columns: 1fr 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
}

@media (max-width: 768px) {
  .header-cta { display: none; }
  .nav { display: none; }
  .menu-toggle { display: flex; }
  .nav.mobile-open {
    display: flex; flex-direction: column; position: fixed;
    top: var(--header-height); left: 0; right: 0; background: var(--bg-white);
    border-bottom: 1px solid var(--border); padding: 16px;
    box-shadow: var(--shadow-xl); max-height: 80vh; overflow-y: auto; z-index: 999;
  }
  .nav.mobile-open .dropdown { display: block; position: static; box-shadow: none; border: none; padding-left: 16px; animation: none; }
  .hero { padding: 56px 20px 68px; }
  .hero h1 { font-size: 26px; }
  .hero p { font-size: 15px; }
  .hero-stats { gap: 24px; }
  .hero-stat-num { font-size: 24px; }
  .products-grid { grid-template-columns: 1fr; }
  .cases-grid { grid-template-columns: 1fr; }
  .news-grid { grid-template-columns: 1fr; }
  .adv-grid { grid-template-columns: 1fr; }
  .footer-inner { grid-template-columns: 1fr; }
  .section { padding: 48px 16px; }
  .section-title h2 { font-size: 23px; }
  .page-header { padding: 40px 20px; }
  .page-header h1 { font-size: 24px; }
}