/* ===== 全局重置与设计系统 ===== */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
:root{
  --brand:#0b1c2f;
  --brand-light:#1a2f4a;
  --accent:#f0c45a;
  --accent2:#d9a542;
  --glass:rgba(255,255,255,0.08);
  --glass-border:rgba(255,255,255,0.12);
  --text-light:#f0f4fa;
  --text-muted:#b0c4de;
  --radius:20px;
  --radius-sm:12px;
  --shadow:0 20px 40px -12px rgba(0,0,0,0.5);
  --card-bg:#112336;
  --transition:0.3s cubic-bezier(0.23,1,0.32,1)
}
body{
  font-family:system-ui,-apple-system,'Segoe UI',Roboto,'Helvetica Neue',sans-serif;
  background:var(--brand);
  color:var(--text-light);
  line-height:1.6;
  overflow-x:hidden;
  scroll-behavior:smooth
}
a{color:var(--accent);text-decoration:none;transition:var(--transition)}
a:hover{color:#fff}
img,svg{display:block;max-width:100%;height:auto}
.container{max-width:1280px;margin:0 auto;padding:0 24px}
.section{padding:80px 0;border-bottom:1px solid rgba(255,255,255,0.04)}
h1,h2,h3{font-weight:600;letter-spacing:-0.02em}
h1{font-size:clamp(2.4rem,6vw,4.2rem);line-height:1.2}
h2{font-size:clamp(1.8rem,4vw,2.8rem);margin-bottom:40px;position:relative;display:inline-block}
h2::after{content:'';display:block;width:60px;height:4px;background:var(--accent);border-radius:4px;margin-top:12px}
h3{font-size:1.4rem;margin-bottom:16px}

/* ===== 按钮 ===== */
.btn{
  display:inline-flex;align-items:center;gap:10px;
  background:var(--accent);color:var(--brand);
  padding:14px 32px;border-radius:60px;font-weight:600;
  transition:var(--transition);border:none;cursor:pointer;
  box-shadow:0 8px 20px rgba(240,196,90,0.25)
}
.btn:hover{background:#fff;transform:translateY(-3px);box-shadow:0 12px 28px rgba(240,196,90,0.35)}
.btn-outline{background:transparent;border:2px solid var(--accent);color:var(--accent);box-shadow:none}
.btn-outline:hover{background:var(--accent);color:var(--brand)}

/* ===== 毛玻璃卡片 ===== */
.glass-card{
  background:var(--glass);
  backdrop-filter:blur(12px);
  -webkit-backdrop-filter:blur(12px);
  border:1px solid var(--glass-border);
  border-radius:var(--radius);
  padding:32px;
  box-shadow:var(--shadow);
  transition:var(--transition)
}
.glass-card:hover{background:rgba(255,255,255,0.12);transform:translateY(-4px)}

/* ===== 导航 ===== */
header{
  position:sticky;top:0;z-index:100;
  background:rgba(11,28,47,0.85);
  backdrop-filter:blur(20px);
  -webkit-backdrop-filter:blur(20px);
  border-bottom:1px solid rgba(255,255,255,0.06)
}
.header-inner{
  display:flex;align-items:center;justify-content:space-between;
  padding:12px 0;flex-wrap:wrap
}
.logo{display:flex;align-items:center;gap:10px;font-size:1.6rem;font-weight:700;color:#fff}
.logo svg{width:38px;height:38px}
.nav{display:flex;gap:8px;flex-wrap:wrap}
.nav a{
  padding:8px 16px;border-radius:40px;
  font-size:0.95rem;font-weight:500;
  color:var(--text-muted);transition:var(--transition)
}
.nav a:hover,.nav a.active{background:var(--glass);color:#fff}
.mobile-toggle{display:none;background:none;border:none;color:#fff;font-size:1.8rem;cursor:pointer;padding:4px 8px}
@media(max-width:768px){
  .nav{display:none;width:100%;flex-direction:column;padding:16px 0;gap:4px}
  .nav.open{display:flex}
  .mobile-toggle{display:block}
}

/* ===== Hero Banner ===== */
.hero{
  min-height:90vh;display:flex;align-items:center;
  position:relative;overflow:hidden;padding:40px 0
}
.hero-bg{
  position:absolute;inset:0;
  background:radial-gradient(circle at 30% 40%,#1f3a5f,var(--brand) 80%);
  z-index:0
}
.hero-bg::after{
  content:'';position:absolute;width:600px;height:600px;border-radius:50%;
  background:var(--accent);opacity:0.05;top:-100px;right:-100px;filter:blur(80px)
}
.hero-content{position:relative;z-index:2;max-width:760px}
.hero h1{margin-bottom:24px}
.hero p{font-size:1.2rem;color:var(--text-muted);margin-bottom:40px;max-width:600px}
.hero-actions{display:flex;gap:16px;flex-wrap:wrap}
.carousel-indicators{display:flex;gap:12px;margin-top:48px}
.dot{
  width:12px;height:12px;border-radius:50%;
  background:var(--text-muted);opacity:0.4;cursor:pointer;transition:var(--transition)
}
.dot.active{opacity:1;background:var(--accent);width:32px;border-radius:6px}

/* ===== 网格布局 ===== */
.grid-2{display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:32px}
.grid-3{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:28px}
.grid-4{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:24px}
.text-center{text-align:center}
.mt-24{margin-top:24px}
.mb-24{margin-bottom:24px}

/* ===== 数字动画 ===== */
.stat-number{font-size:2.8rem;font-weight:700;color:var(--accent);line-height:1.2}
.stat-label{color:var(--text-muted);font-size:1rem}

/* ===== 文章卡片 ===== */
.article-card{
  padding:24px;background:var(--card-bg);
  border-radius:var(--radius-sm);border-left:4px solid var(--accent);
  transition:var(--transition)
}
.article-card:hover{background:var(--brand-light);transform:translateY(-4px)}
.article-card .date{font-size:0.85rem;color:var(--text-muted);margin-bottom:6px}
.article-card h3{margin-bottom:8px}
.article-card p{color:var(--text-muted);font-size:0.95rem;margin-bottom:16px}

/* ===== FAQ折叠 ===== */
.faq-item{border-bottom:1px solid rgba(255,255,255,0.08);padding:16px 0}
.faq-question{
  display:flex;justify-content:space-between;align-items:center;
  cursor:pointer;font-weight:500;font-size:1.1rem;padding:8px 0
}
.faq-question span{transition:var(--transition)}
.faq-answer{max-height:0;overflow:hidden;transition:max-height 0.4s ease;color:var(--text-muted);padding-left:8px}
.faq-answer.open{max-height:600px;padding-top:12px}

/* ===== 页脚 ===== */
footer{
  background:rgba(0,0,0,0.4);padding:48px 0 24px;
  border-top:1px solid rgba(255,255,255,0.06)
}
.footer-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:32px;margin-bottom:32px}
.footer-grid h4{color:var(--accent);margin-bottom:16px;font-size:1rem}
.footer-grid a,.footer-grid p{color:var(--text-muted);font-size:0.9rem;display:block;margin-bottom:6px}
.footer-bottom{text-align:center;border-top:1px solid rgba(255,255,255,0.06);padding-top:24px;font-size:0.85rem;color:var(--text-muted)}

/* ===== 明亮模式 ===== */
body.light-mode{
  --brand:#f5f8fe;--brand-light:#e2e9f5;
  --text-light:#0b1c2f;--text-muted:#3a4b60;
  --card-bg:#ffffff;
  --glass:rgba(0,0,0,0.03);--glass-border:rgba(0,0,0,0.08);
  --shadow:0 20px 40px -12px rgba(0,0,0,0.15)
}
body.light-mode header{background:rgba(245,248,254,0.85)}
body.light-mode .hero-bg{background:radial-gradient(circle at 30% 40%,#dce6f5,#f5f8fe 80%)}
body.light-mode .btn{color:#0b1c2f}

/* ===== 滚动动画 ===== */
.fade-up{opacity:0;transform:translateY(30px);transition:opacity 0.7s ease,transform 0.7s ease}
.fade-up.visible{opacity:1;transform:translateY(0)}

/* ===== 工具类 ===== */
.flex-center{display:flex;align-items:center;justify-content:center}
.gap-16{gap:16px}

/* ===== 返回顶部 ===== */
.back-to-top{
  position:fixed;bottom:30px;right:30px;
  background:var(--accent);color:var(--brand);
  width:48px;height:48px;border-radius:50%;
  display:flex;align-items:center;justify-content:center;
  font-size:1.8rem;box-shadow:0 8px 20px rgba(0,0,0,0.4);
  cursor:pointer;z-index:99;border:none;
  transition:var(--transition);opacity:0;pointer-events:none
}
.back-to-top.show{opacity:1;pointer-events:auto}
.back-to-top:hover{transform:scale(1.1);background:#fff}