*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
:root{
  --primary:#2AABEE;
  --primary-dark:#229ED9;
  --bg:#0f1419;
  --bg-card:#1a2332;
  --bg-card-hover:#223044;
  --text:#e8edf3;
  --text-muted:#8b9cb3;
  --border:#2a3548;
  --radius:12px;
  --shadow:0 4px 24px rgba(0,0,0,.35);
  --max-w:1140px;
}
html{scroll-behavior:smooth}
body{
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  background:var(--bg);
  color:var(--text);
  line-height:1.7;
  font-size:16px;
}
a{color:var(--primary);text-decoration:none;transition:color .2s}
a:hover{color:var(--primary-dark)}
img{max-width:100%;height:auto;display:block}
.container{max-width:var(--max-w);margin:0 auto;padding:0 20px}

/* Header */
.site-header{
  position:sticky;top:0;z-index:100;
  background:rgba(15,20,25,.92);
  backdrop-filter:blur(12px);
  border-bottom:1px solid var(--border);
}
.header-inner{
  display:flex;align-items:center;justify-content:space-between;
  height:64px;
}
.logo{
  display:flex;align-items:center;gap:10px;
  font-size:1.25rem;font-weight:700;color:var(--text);
}
.logo svg{width:32px;height:32px}
.nav{display:flex;align-items:center;gap:28px}
.nav a{color:var(--text-muted);font-size:.95rem}
.nav a:hover,.nav a.active{color:var(--primary)}
.btn-download{
  display:inline-flex;align-items:center;gap:8px;
  background:var(--primary);color:#fff!important;
  padding:10px 22px;border-radius:8px;font-weight:600;
  transition:background .2s,transform .15s;
}
.btn-download:hover{background:var(--primary-dark);transform:translateY(-1px)}
.menu-toggle{display:none;background:none;border:none;color:var(--text);font-size:1.5rem;cursor:pointer}

/* Hero */
.hero{
  padding:80px 0 60px;
  background:linear-gradient(180deg,rgba(42,171,238,.08) 0%,transparent 60%);
}
.hero-badge{
  display:inline-block;
  background:rgba(42,171,238,.15);color:var(--primary);
  padding:6px 14px;border-radius:20px;font-size:.85rem;
  margin-bottom:20px;
}
.hero h1{
  font-size:clamp(1.8rem,4vw,2.75rem);
  line-height:1.3;margin-bottom:20px;
  background:linear-gradient(135deg,#fff 0%,#a8d4f5 100%);
  -webkit-background-clip:text;-webkit-text-fill-color:transparent;
  background-clip:text;
}
.hero-desc{
  font-size:1.1rem;color:var(--text-muted);
  max-width:680px;margin-bottom:32px;
}
.hero-actions{display:flex;flex-wrap:wrap;gap:14px;align-items:center}
.hero-meta{margin-top:24px;font-size:.9rem;color:var(--text-muted)}

/* Sections */
section{padding:60px 0}
.section-label{
  font-size:.8rem;text-transform:uppercase;letter-spacing:2px;
  color:var(--primary);margin-bottom:8px;
}
.section-title{
  font-size:clamp(1.4rem,3vw,2rem);
  margin-bottom:12px;
}
.section-desc{color:var(--text-muted);margin-bottom:40px;max-width:640px}

/* Steps */
.steps-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:20px}
.step-card{
  background:var(--bg-card);border:1px solid var(--border);
  border-radius:var(--radius);padding:28px;
  transition:border-color .2s,transform .2s;
}
.step-card:hover{border-color:var(--primary);transform:translateY(-3px)}
.step-num{
  display:inline-block;
  font-size:.75rem;font-weight:700;color:var(--primary);
  background:rgba(42,171,238,.12);padding:4px 10px;border-radius:6px;
  margin-bottom:14px;
}
.step-card h3{font-size:1.05rem;margin-bottom:10px}
.step-card p{color:var(--text-muted);font-size:.92rem;margin-bottom:16px}
.step-link{font-size:.9rem;font-weight:600}

/* Articles grid */
.articles-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(300px,1fr));gap:20px}
.article-card{
  background:var(--bg-card);border:1px solid var(--border);
  border-radius:var(--radius);overflow:hidden;
  transition:border-color .2s,transform .2s;
}
.article-card:hover{border-color:var(--primary);transform:translateY(-3px)}
.article-card-body{padding:24px}
.article-card h3{font-size:1.05rem;margin-bottom:10px;line-height:1.4}
.article-card h3 a{color:var(--text)}
.article-card h3 a:hover{color:var(--primary)}
.article-card p{color:var(--text-muted);font-size:.9rem;margin-bottom:14px}
.article-meta{font-size:.8rem;color:var(--text-muted)}

/* FAQ */
.faq-list{max-width:800px}
.faq-item{
  border:1px solid var(--border);border-radius:var(--radius);
  margin-bottom:12px;overflow:hidden;
}
.faq-q{
  width:100%;text-align:left;background:var(--bg-card);
  border:none;color:var(--text);padding:20px 24px;
  font-size:1rem;font-weight:600;cursor:pointer;
  display:flex;justify-content:space-between;align-items:center;
}
.faq-q::after{content:"+";font-size:1.2rem;color:var(--primary);transition:transform .2s}
.faq-item.open .faq-q::after{transform:rotate(45deg)}
.faq-a{
  display:none;padding:0 24px 20px;
  color:var(--text-muted);font-size:.95rem;
}
.faq-item.open .faq-a{display:block}

/* Download page */
.download-platforms{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:20px;margin-top:32px}
.platform-card{
  background:var(--bg-card);border:1px solid var(--border);
  border-radius:var(--radius);padding:32px 24px;text-align:center;
}
.platform-icon{font-size:2.5rem;margin-bottom:16px}
.platform-card h3{margin-bottom:8px}
.platform-card p{color:var(--text-muted);font-size:.9rem;margin-bottom:20px}
.platform-card .btn-download{width:100%;justify-content:center}

/* Article page */
.article-header{padding:60px 0 30px}
.article-header h1{font-size:clamp(1.5rem,3vw,2.2rem);line-height:1.35;margin-bottom:16px}
.article-content{
  max-width:760px;margin:0 auto;padding:0 20px 60px;
}
.article-content h2{font-size:1.35rem;margin:36px 0 14px;color:var(--text)}
.article-content h3{font-size:1.1rem;margin:28px 0 10px}
.article-content p{margin-bottom:16px;color:var(--text-muted)}
.article-content ul,.article-content ol{margin:0 0 16px 24px;color:var(--text-muted)}
.article-content li{margin-bottom:8px}
.article-content strong{color:var(--text)}
.article-toc{
  background:var(--bg-card);border:1px solid var(--border);
  border-radius:var(--radius);padding:24px;margin-bottom:36px;
}
.article-toc h4{margin-bottom:12px;font-size:.95rem}
.article-toc ul{list-style:none;margin:0;padding:0}
.article-toc li{margin-bottom:6px}
.article-toc a{font-size:.9rem}

/* Footer */
.site-footer{
  border-top:1px solid var(--border);
  padding:40px 0 30px;margin-top:40px;
}
.footer-grid{
  display:grid;grid-template-columns:2fr 1fr 1fr;gap:40px;
  margin-bottom:30px;
}
.footer-brand p{color:var(--text-muted);font-size:.9rem;margin-top:12px;max-width:360px}
.footer-col h4{font-size:.9rem;margin-bottom:14px;color:var(--text)}
.footer-col ul{list-style:none}
.footer-col li{margin-bottom:8px}
.footer-col a{color:var(--text-muted);font-size:.9rem}
.footer-col a:hover{color:var(--primary)}
.footer-bottom{
  border-top:1px solid var(--border);padding-top:20px;
  display:flex;justify-content:space-between;flex-wrap:wrap;gap:10px;
  font-size:.85rem;color:var(--text-muted);
}

/* Breadcrumb */
.breadcrumb{padding:20px 0;font-size:.85rem;color:var(--text-muted)}
.breadcrumb a{color:var(--text-muted)}
.breadcrumb a:hover{color:var(--primary)}
.breadcrumb span{margin:0 8px}

/* Features */
.features-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:20px}
.feature-card{
  background:var(--bg-card);border:1px solid var(--border);
  border-radius:var(--radius);padding:28px;
}
.feature-card h3{font-size:1.05rem;margin-bottom:10px}
.feature-card p{color:var(--text-muted);font-size:.92rem}

/* Responsive */
@media(max-width:768px){
  .nav{display:none;position:absolute;top:64px;left:0;right:0;
    flex-direction:column;background:var(--bg);padding:20px;
    border-bottom:1px solid var(--border);gap:16px}
  .nav.open{display:flex}
  .menu-toggle{display:block}
  .footer-grid{grid-template-columns:1fr}
  .hero{padding:50px 0 40px}
}