/* RESET & BASE */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body { font-family: system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif; background: linear-gradient(135deg, #f0f5ff 0%, #e8f0fe 100%); color: #1a2634; line-height: 1.6; transition: background 0.3s, color 0.3s; min-height: 100vh; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }
img, svg { display: block; max-width: 100%; height: auto; }

/* 暗黑模式 */
@media (prefers-color-scheme: dark) {
  body { background: linear-gradient(135deg, #0b1120 0%, #141e33 100%); color: #e2e8f0; }
  .glass, .card, .section, footer, header, .nav-wrapper, .hero, .faq-item, .howto-step, .article-card, .testimonial-card, .team-card, .value-card, .solution-card, .case-card, .news-card { background: rgba(30, 41, 59, 0.65) !important; backdrop-filter: blur(12px); border-color: rgba(100, 120, 150, 0.25) !important; }
  .btn-primary { background: linear-gradient(135deg, #2563eb, #1d4ed8) !important; }
  .text-muted { color: #94a3b8 !important; }
  .brand { color: #60a5fa !important; }
  .stat-number { color: #60a5fa !important; }
  .carousel-item { background: linear-gradient(135deg, #1a2744, #0f1b33) !important; }
  .badge { background: rgba(96, 165, 250, 0.15) !important; }
  .search-sim input { background: rgba(30, 41, 59, 0.6) !important; border-color: #3b4a6b !important; color: #e2e8f0; }
}

/* 玻璃、阴影、圆角体系 */
.glass, .card, .section, .faq-item, .howto-step, .article-card, .testimonial-card, .team-card, .value-card, .solution-card, .case-card, .news-card { background: rgba(255,255,255,0.65); backdrop-filter: blur(14px); border-radius: 28px; box-shadow: 0 20px 40px -12px rgba(0,20,40,0.12), 0 4px 8px rgba(0,0,0,0.02); padding: 2rem; transition: transform 0.25s ease, box-shadow 0.3s ease; border: 1px solid rgba(255,255,255,0.35); }
.card:hover { transform: translateY(-6px); box-shadow: 0 30px 50px -16px rgba(0,20,50,0.2); }
.container { max-width: 1280px; margin: 0 auto; padding: 0 1.5rem; }
.section { margin: 3rem 0; padding: 2.5rem 2rem; }
.flex { display: flex; flex-wrap: wrap; align-items: center; justify-content: center; gap: 2rem; }
.grid { display: grid; gap: 2rem; }

/* 按钮 */
.btn-primary { background: linear-gradient(135deg, #0b2b5c, #1e4b8a); color: #fff; padding: 0.85rem 2.2rem; border-radius: 60px; font-weight: 600; border: none; cursor: pointer; transition: all 0.3s ease; display: inline-block; box-shadow: 0 8px 22px -6px rgba(11,43,92,0.5); font-size: 1rem; letter-spacing: 0.02em; }
.btn-primary:hover { transform: scale(1.03); box-shadow: 0 14px 32px -8px rgba(11,43,92,0.7); }
.text-muted { color: #4a5a72; }
.brand { color: #0b2b5c; font-weight: 700; }

/* 标题 */
h1 { font-size: 2.8rem; font-weight: 700; line-height: 1.2; letter-spacing: -0.01em; background: linear-gradient(135deg, #0b2b5c, #2563eb); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
h2 { font-size: 2rem; margin-bottom: 0.5rem; font-weight: 600; position: relative; display: inline-block; }
h2::after { content: ''; display: block; width: 60px; height: 4px; background: linear-gradient(135deg, #0b2b5c, #2563eb); border-radius: 4px; margin-top: 0.5rem; }
h3 { font-size: 1.4rem; font-weight: 600; }

/* header 吸顶 */
.site-header { position: sticky; top: 0; z-index: 100; background: rgba(255,255,255,0.7); backdrop-filter: blur(18px); border-bottom: 1px solid rgba(255,255,255,0.15); box-shadow: 0 4px 24px rgba(0,0,0,0.03); }
.nav-wrapper { display: flex; justify-content: space-between; align-items: center; padding: 0.8rem 1.5rem; max-width: 1280px; margin: 0 auto; }
.logo svg { height: 44px; width: auto; filter: drop-shadow(0 2px 4px rgba(0,0,0,0.1)); }
.nav-menu { display: flex; gap: 1.2rem; font-weight: 500; align-items: center; }
.nav-menu a { padding: 0.5rem 0.2rem; border-bottom: 2px solid transparent; transition: border-color 0.2s, color 0.2s; position: relative; }
.nav-menu a:hover, .nav-menu a.active { border-bottom-color: #0b2b5c; color: #0b2b5c; }
.nav-menu a::after { content: ''; position: absolute; bottom: -2px; left: 0; width: 0; height: 2px; background: #0b2b5c; transition: width 0.3s; }
.nav-menu a:hover::after, .nav-menu a.active::after { width: 100%; }
.mobile-toggle { display: none; background: none; border: none; font-size: 2rem; cursor: pointer; color: inherit; padding: 0.2rem; }
.dark-toggle { background: none; border: none; font-size: 1.6rem; cursor: pointer; color: inherit; padding: 0 0.5rem; transition: transform 0.2s; }
.dark-toggle:hover { transform: rotate(20deg); }

/* 移动菜单 */
@media (max-width: 900px) {
  .nav-menu { display: none; flex-direction: column; background: rgba(255,255,255,0.92); backdrop-filter: blur(24px); position: absolute; top: 68px; left: 0; width: 100%; padding: 1.5rem 2rem; border-radius: 0 0 32px 32px; box-shadow: 0 24px 48px rgba(0,0,0,0.12); gap: 0.8rem; }
  .nav-menu.open { display: flex; }
  .mobile-toggle { display: block; }
  h1 { font-size: 2rem; }
  h2 { font-size: 1.6rem; }
  .section { padding: 1.8rem 1.2rem; margin: 2rem 0; }
  .container { padding: 0 1rem; }
}

/* 轮播 */
.carousel { position: relative; overflow: hidden; border-radius: 32px; }
.carousel-inner { display: flex; transition: transform 0.7s cubic-bezier(0.25, 0.46, 0.45, 0.94); }
.carousel-item { min-width: 100%; padding: 3.5rem 2.5rem; background: linear-gradient(135deg, #dce7f5, #b8cce4); border-radius: 32px; min-height: 340px; display: flex; flex-direction: column; justify-content: center; }
.carousel-control { position: absolute; top: 50%; transform: translateY(-50%); background: rgba(255,255,255,0.5); backdrop-filter: blur(6px); border: none; border-radius: 50%; width: 50px; height: 50px; font-size: 2.2rem; cursor: pointer; box-shadow: 0 4px 14px rgba(0,0,0,0.08); transition: all 0.2s; color: #0b2b5c; display: flex; align-items: center; justify-content: center; line-height: 1; }
.carousel-control:hover { background: rgba(255,255,255,0.85); transform: translateY(-50%) scale(1.05); }
.carousel-control.prev { left: 1rem; }
.carousel-control.next { right: 1rem; }

/* 数字动画 */
.stat-number { font-size: 2.8rem; font-weight: 800; color: #0b2b5c; line-height: 1; }

/* 滚动动画 */
.fade-in { opacity: 0; transform: translateY(24px); transition: opacity 0.7s ease, transform 0.7s ease; }
.fade-in.visible { opacity: 1; transform: translateY(0); }

/* footer */
footer { background: rgba(11,43,92,0.04); border-radius: 32px 32px 0 0; padding: 2.5rem 1.5rem; margin-top: 3rem; backdrop-filter: blur(6px); border-top: 1px solid rgba(255,255,255,0.15); }
.footer-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 2rem; }
footer h4 { font-weight: 600; margin-bottom: 0.8rem; color: #0b2b5c; }
footer ul li { padding: 0.3rem 0; opacity: 0.8; transition: opacity 0.2s; }
footer ul li:hover { opacity: 1; }

/* FAQ折叠 */
.faq-item { margin-bottom: 1rem; padding: 1.2rem 1.5rem; border-radius: 24px; cursor: pointer; transition: background 0.2s; }
.faq-item:hover { background: rgba(11,43,92,0.03); }
.faq-question { font-weight: 600; display: flex; justify-content: space-between; align-items: center; font-size: 1.05rem; }
.faq-question span { font-size: 1.5rem; transition: transform 0.3s; }
.faq-item.open .faq-question span { transform: rotate(45deg); }
.faq-answer { max-height: 0; overflow: hidden; transition: max-height 0.45s ease, padding 0.3s; margin-top: 0.5rem; padding: 0 0.2rem; color: #4a5a72; }
.faq-item.open .faq-answer { max-height: 300px; padding: 0.5rem 0.2rem; }

/* 搜索模拟 */
.search-sim { display: flex; gap: 0.5rem; max-width: 420px; margin: 1rem 0; }
.search-sim input { flex: 1; padding: 0.8rem 1.4rem; border-radius: 60px; border: 1px solid rgba(200,210,220,0.5); background: rgba(255,255,255,0.5); backdrop-filter: blur(6px); font-size: 1rem; transition: border-color 0.2s; }
.search-sim input:focus { outline: none; border-color: #0b2b5c; box-shadow: 0 0 0 3px rgba(11,43,92,0.1); }

/* 返回顶部 */
.back-to-top { position: fixed; bottom: 2rem; right: 2rem; background: #0b2b5c; color: white; border: none; border-radius: 50%; width: 52px; height: 52px; font-size: 1.8rem; cursor: pointer; box-shadow: 0 8px 24px rgba(0,0,0,0.3); display: none; z-index: 200; transition: transform 0.2s, background 0.2s; }
.back-to-top:hover { transform: scale(1.08); background: #1e4b8a; }

/* 文章卡片网格 */
.article-grid, .faq-grid, .case-grid, .team-grid, .value-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 2rem; }
.badge { background: rgba(11,43,92,0.12); padding: 0.3rem 1rem; border-radius: 40px; font-size: 0.85rem; display: inline-block; transition: background 0.2s; }
.badge:hover { background: rgba(11,43,92,0.2); }
hr { opacity: 0.1; margin: 2rem 0; }

/* 其他卡片微调 */
.testimonial-card, .howto-step { margin-bottom: 1rem; }
.howto-step + .howto-step { margin-top: 0.5rem; }
.case-grid .card, .value-grid .card { min-height: 180px; display: flex; flex-direction: column; justify-content: center; }

/* 响应式微调 */
@media (max-width: 640px) {
  .carousel-item { min-height: 260px; padding: 2rem 1.5rem; }
  .stat-number { font-size: 2rem; }
  .btn-primary { padding: 0.7rem 1.6rem; font-size: 0.95rem; }
  .flex { gap: 1.2rem; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}