/* 全局重置 & 品牌设计系统 */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
:root {
  --brand-primary: #0a1a2b; /* 深蓝黑 */
  --brand-secondary: #1a3b5c;
  --brand-accent: #e8b830; /* 金色 */
  --brand-light: #f4f7fc;
  --brand-white: #ffffff;
  --brand-dark: #0e1e2f;
  --brand-gradient: linear-gradient(135deg, #0a1a2b 0%, #1f4b6e 100%);
  --glass-bg: rgba(255,255,255,0.12);
  --glass-border: rgba(255,255,255,0.2);
  --shadow-sm: 0 8px 20px rgba(0,0,0,0.08);
  --shadow-md: 0 16px 40px rgba(0,0,0,0.12);
  --radius-sm: 12px;
  --radius-md: 24px;
  --radius-lg: 32px;
  --transition: all 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
}
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: var(--font-sans);
  background: var(--brand-light);
  color: #1a1a2e;
  line-height: 1.6;
  transition: background 0.3s, color 0.3s;
}
/* 暗黑模式 */
@media (prefers-color-scheme: dark) {
  body { background: #0e1218; color: #eef2f6; }
  .card, .section-glass, .faq-item, .article-card, .team-card, .case-card, .footer, .header { background: #1a1f2a !important; color: #eef2f6; }
  .hero { background: #0a111c !important; }
  .nav-link, .text-muted { color: #b0b8c8 !important; }
  .brand-logo-text { fill: #e8b830; }
}
/* 布局 */
.container { max-width: 1280px; margin: 0 auto; padding: 0 24px; }
.section { padding: 80px 0; }
.section-title { font-size: 2.4rem; font-weight: 700; margin-bottom: 1.2rem; letter-spacing: -0.02em; }
.section-sub { font-size: 1.1rem; color: #4a5a6e; max-width: 720px; margin-bottom: 3rem; }
/* 玻璃效果 */
.glass { background: var(--glass-bg); backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px); border: 1px solid var(--glass-border); border-radius: var(--radius-md); }
/* 卡片 */
.card { background: var(--brand-white); border-radius: var(--radius-md); box-shadow: var(--shadow-sm); transition: var(--transition); padding: 2rem; }
.card:hover { transform: translateY(-6px); box-shadow: var(--shadow-md); }
/* 按钮 */
.btn { display: inline-flex; align-items: center; gap: 8px; padding: 12px 28px; border-radius: 60px; font-weight: 600; border: none; cursor: pointer; transition: var(--transition); text-decoration: none; }
.btn-primary { background: var(--brand-accent); color: #0a1a2b; }
.btn-primary:hover { background: #d4a520; transform: scale(1.02); }
.btn-outline { background: transparent; border: 2px solid var(--brand-accent); color: var(--brand-accent); }
.btn-outline:hover { background: var(--brand-accent); color: #0a1a2b; }
/* 导航 */
.header { position: fixed; top: 0; width: 100%; z-index: 100; background: rgba(10,26,43,0.85); backdrop-filter: blur(16px); border-bottom: 1px solid rgba(255,255,255,0.06); }
.header .container { display: flex; align-items: center; justify-content: space-between; height: 68px; }
.logo svg { height: 40px; width: auto; }
.nav { display: flex; gap: 32px; }
.nav-link { color: rgba(255,255,255,0.8); text-decoration: none; font-weight: 500; font-size: 0.95rem; position: relative; transition: var(--transition); }
.nav-link:hover, .nav-link.active { color: var(--brand-accent); }
.nav-link::after { content: ''; position: absolute; bottom: -4px; left: 0; width: 0; height: 2px; background: var(--brand-accent); transition: var(--transition); }
.nav-link:hover::after, .nav-link.active::after { width: 100%; }
.mobile-toggle { display: none; background: none; border: none; color: white; font-size: 28px; cursor: pointer; }
.dark-toggle { background: none; border: 1px solid rgba(255,255,255,0.3); border-radius: 40px; padding: 6px 14px; color: white; font-size: 1rem; cursor: pointer; transition: var(--transition); }
/* 移动菜单 */
@media (max-width: 900px) {
  .nav { display: none; flex-direction: column; background: rgba(10,26,43,0.98); position: absolute; top: 68px; left: 0; right: 0; padding: 24px; gap: 20px; border-bottom: 2px solid var(--brand-accent); }
  .nav.open { display: flex; }
  .mobile-toggle { display: block; }
}
/* Hero Banner 轮播 */
.hero { background: var(--brand-gradient); padding: 140px 0 80px; color: white; position: relative; overflow: hidden; }
.hero-grid { display: flex; align-items: center; gap: 40px; flex-wrap: wrap; }
.hero-text { flex: 1 1 400px; }
.hero-visual { flex: 1 1 320px; min-height: 280px; }
.hero h1 { font-size: 3.2rem; font-weight: 800; line-height: 1.2; margin-bottom: 24px; }
.hero p { font-size: 1.2rem; opacity: 0.85; max-width: 600px; margin-bottom: 32px; }
.hero-actions { display: flex; gap: 16px; flex-wrap: wrap; }
/* 轮播指示器 */
.carousel-indicators { display: flex; gap: 12px; margin-top: 40px; justify-content: center; }
.dot { width: 12px; height: 12px; border-radius: 50%; background: rgba(255,255,255,0.3); border: none; cursor: pointer; transition: var(--transition); }
.dot.active { background: var(--brand-accent); transform: scale(1.2); }
/* 产品/卡片网格 */
.grid-4 { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 32px; }
.grid-3 { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 32px; }
.grid-2 { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 32px; }
/* FAQ折叠 */
.faq-item { background: white; border-radius: var(--radius-sm); margin-bottom: 16px; box-shadow: 0 2px 8px rgba(0,0,0,0.04); overflow: hidden; }
.faq-question { padding: 18px 24px; font-weight: 600; cursor: pointer; display: flex; justify-content: space-between; align-items: center; border: none; background: transparent; width: 100%; text-align: left; font-size: 1.1rem; }
.faq-question::after { content: '+'; font-size: 1.6rem; transition: var(--transition); }
.faq-item.open .faq-question::after { transform: rotate(45deg); }
.faq-answer { max-height: 0; overflow: hidden; transition: max-height 0.4s ease; padding: 0 24px; }
.faq-item.open .faq-answer { max-height: 400px; padding: 0 24px 20px; }
/* 团队 */
.team-card { text-align: center; }
.team-avatar { width: 100px; height: 100px; border-radius: 50%; background: var(--brand-secondary); margin: 0 auto 16px; display: flex; align-items: center; justify-content: center; color: white; font-weight: bold; font-size: 2rem; }
/* 页脚 */
.footer { background: var(--brand-primary); color: #ccd4e0; padding: 48px 0 24px; }
.footer-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(160px,1fr)); gap: 32px; }
.footer a { color: #b0c4de; text-decoration: none; }
.footer a:hover { color: var(--brand-accent); }
.footer-bottom { border-top: 1px solid rgba(255,255,255,0.08); margin-top: 32px; padding-top: 24px; display: flex; flex-wrap: wrap; justify-content: space-between; gap: 12px; }
/* 动画 */
.scroll-hidden { opacity: 0; transform: translateY(30px); transition: opacity 0.6s ease, transform 0.6s ease; }
.scroll-visible { opacity: 1; transform: translateY(0); }
/* 数字动画 */
.stat-number { font-size: 2.8rem; font-weight: 800; color: var(--brand-accent); }
/* 返回顶部 */
#backTop { position: fixed; bottom: 40px; right: 30px; background: var(--brand-accent); color: #0a1a2b; width: 48px; height: 48px; border-radius: 50%; display: flex; align-items: center; justify-content: center; font-size: 1.6rem; box-shadow: var(--shadow-md); cursor: pointer; transition: var(--transition); opacity: 0; visibility: hidden; z-index: 200; border: none; }
#backTop.show { opacity: 1; visibility: visible; }
/* 搜索模拟 */
.search-modal { display: none; position: fixed; inset: 0; background: rgba(0,0,0,0.6); z-index: 300; justify-content: center; align-items: center; }
.search-modal.open { display: flex; }
.search-box { background: white; padding: 32px; border-radius: var(--radius-md); width: 90%; max-width: 480px; }
.search-box input { width: 100%; padding: 14px; border: 2px solid #ddd; border-radius: 40px; font-size: 1rem; }
/* 图片占位SVG自适应 */
.img-svg { width: 100%; height: auto; display: block; }
/* 文章卡片 */
.article-card { padding: 1.6rem; }
.article-meta { color: #6b7a8a; font-size: 0.9rem; }
/* 响应式 */
@media (max-width: 640px) {
  .section-title { font-size: 1.8rem; }
  .hero h1 { font-size: 2.2rem; }
  .header .container { height: 60px; }
}