/* ========== CSS Reset & Base ========== */
*,*::before,*::after{margin:0;padding:0;box-sizing:border-box}
:root{
  --primary:#1a73e8;
  --primary-dark:#0d47a1;
  --accent:#00e5ff;
  --accent-dark:#0091ea;
  --bg-dark:#0a0e1a;
  --bg-card:#111827;
  --bg-card-hover:#1e293b;
  --text:#e2e8f0;
  --text-muted:#94a3b8;
  --text-bright:#f8fafc;
  --border:#1e3a5f;
  --gradient-hero:linear-gradient(135deg,#0a0e1a 0%,#0f2847 50%,#0a1628 100%);
  --gradient-card:linear-gradient(145deg,#111827,#1a2744);
  --gradient-btn:linear-gradient(135deg,#1a73e8,#00b4d8);
  --gradient-accent:linear-gradient(135deg,#00e5ff,#0091ea);
  --shadow:0 4px 24px rgba(0,0,0,.4);
  --shadow-glow:0 0 30px rgba(26,115,232,.3);
  --radius:12px;
  --radius-lg:20px;
}
html{scroll-behavior:smooth;font-size:16px}
body{
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  background:var(--bg-dark);color:var(--text);line-height:1.7;overflow-x:hidden;
}
a{color:var(--accent);text-decoration:none;transition:color .2s}
a:hover{color:var(--text-bright)}
img{max-width:100%;display:block}
ul,ol{list-style:none}

/* ========== Scrollbar ========== */
::-webkit-scrollbar{width:8px}
::-webkit-scrollbar-track{background:var(--bg-dark)}
::-webkit-scrollbar-thumb{background:var(--primary);border-radius:4px}

/* ========== Navigation ========== */
.navbar{
  position:fixed;top:0;left:0;width:100%;z-index:1000;
  background:rgba(10,14,26,.92);backdrop-filter:blur(16px);
  border-bottom:1px solid var(--border);transition:all .3s;
}
.navbar .nav-inner{
  max-width:1280px;margin:0 auto;padding:0 24px;
  display:flex;align-items:center;justify-content:space-between;height:64px;
}
.navbar .logo{
  font-size:1.35rem;font-weight:800;letter-spacing:1px;
  background:linear-gradient(90deg,var(--accent),var(--primary));
  -webkit-background-clip:text;-webkit-text-fill-color:transparent;
}
.navbar .logo span{font-size:.75rem;color:var(--text-muted);margin-left:8px;font-weight:400;-webkit-text-fill-color:var(--text-muted)}
.navbar nav ul{display:flex;gap:8px}
.navbar nav a{
  display:inline-block;padding:8px 16px;border-radius:8px;
  color:var(--text-muted);font-size:.9rem;font-weight:500;transition:all .2s;
}
.navbar nav a:hover,.navbar nav a.active{
  color:var(--text-bright);background:rgba(26,115,232,.15);
}
.mobile-menu-btn{display:none;background:none;border:none;color:var(--text);font-size:1.5rem;cursor:pointer;padding:8px}

/* ========== Hero Section ========== */
.hero{
  min-height:100vh;display:flex;align-items:center;justify-content:center;
  background:var(--gradient-hero);position:relative;overflow:hidden;
  padding:80px 24px 60px;
}
.hero::before{
  content:'';position:absolute;top:-50%;left:-50%;width:200%;height:200%;
  background:radial-gradient(ellipse at 30% 20%,rgba(26,115,232,.12) 0%,transparent 60%),
             radial-gradient(ellipse at 70% 80%,rgba(0,229,255,.08) 0%,transparent 60%);
  animation:heroGlow 8s ease-in-out infinite alternate;
}
@keyframes heroGlow{
  0%{transform:translate(0,0) scale(1)}
  100%{transform:translate(-3%,3%) scale(1.05)}
}
.hero-inner{max-width:900px;text-align:center;position:relative;z-index:1}
.hero-badge{
  display:inline-block;padding:6px 20px;border-radius:30px;
  background:rgba(0,229,255,.1);border:1px solid rgba(0,229,255,.3);
  color:var(--accent);font-size:.85rem;margin-bottom:24px;
  animation:badgePulse 2s ease-in-out infinite;
}
@keyframes badgePulse{
  0%,100%{box-shadow:0 0 0 0 rgba(0,229,255,.3)}
  50%{box-shadow:0 0 0 8px rgba(0,229,255,0)}
}
.hero h1{
  font-size:clamp(2rem,5.5vw,3.8rem);font-weight:900;line-height:1.15;
  margin-bottom:20px;
}
.hero h1 .gradient-text{
  background:linear-gradient(135deg,var(--accent),var(--primary),#a78bfa);
  -webkit-background-clip:text;-webkit-text-fill-color:transparent;
}
.hero p{font-size:clamp(1rem,2.5vw,1.2rem);color:var(--text-muted);margin-bottom:36px;max-width:700px;margin-left:auto;margin-right:auto}
.hero-buttons{display:flex;gap:16px;justify-content:center;flex-wrap:wrap}
.btn{
  display:inline-flex;align-items:center;gap:8px;padding:14px 36px;
  border-radius:12px;font-size:1rem;font-weight:600;cursor:pointer;
  border:none;transition:all .3s;letter-spacing:.5px;
}
.btn-primary{
  background:var(--gradient-btn);color:#fff;box-shadow:var(--shadow-glow);
}
.btn-primary:hover{transform:translateY(-2px);box-shadow:0 0 40px rgba(26,115,232,.5)}
.btn-outline{
  background:transparent;color:var(--accent);border:1.5px solid var(--accent);
}
.btn-outline:hover{background:rgba(0,229,255,.08);transform:translateY(-2px)}

/* ========== Section Common ========== */
.section{padding:80px 24px}
.section-header{text-align:center;margin-bottom:56px}
.section-header h2{
  font-size:clamp(1.5rem,3.5vw,2.2rem);font-weight:800;margin-bottom:12px;
}
.section-header p{color:var(--text-muted);font-size:1.05rem;max-width:650px;margin:0 auto}
.section-header .accent-line{
  width:60px;height:4px;border-radius:2px;margin:0 auto 16px;
  background:var(--gradient-accent);
}

/* ========== Image Showcase (3 Main Images) ========== */
.showcase-grid{
  max-width:1200px;margin:0 auto;display:grid;
  grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:24px;
}
.showcase-card{
  position:relative;border-radius:var(--radius-lg);overflow:hidden;
  background:var(--gradient-card);border:1px solid var(--border);
  transition:transform .35s,box-shadow .35s;
}
.showcase-card:hover{transform:translateY(-6px);box-shadow:var(--shadow-glow)}
.showcase-card .img-placeholder{
  width:100%;aspect-ratio:16/9;display:flex;align-items:center;justify-content:center;
  font-size:3rem;
  background:linear-gradient(135deg,#0f2847,#1a365d,#0f2847);
  position:relative;overflow:hidden;
}
.showcase-card .img-placeholder::after{
  content:'';position:absolute;inset:0;
  background:linear-gradient(45deg,transparent 40%,rgba(0,229,255,.05) 50%,transparent 60%);
  animation:shimmer 3s infinite;
}
@keyframes shimmer{0%{transform:translateX(-100%)}100%{transform:translateX(100%)}}
.showcase-card .card-body{padding:20px 24px 24px}
.showcase-card .card-body h3{font-size:1.15rem;margin-bottom:8px;color:var(--text-bright)}
.showcase-card .card-body p{font-size:.9rem;color:var(--text-muted)}

/* ========== Features Grid ========== */
.features-grid{
  max-width:1200px;margin:0 auto;display:grid;
  grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:20px;
}
.feature-card{
  padding:28px 24px;border-radius:var(--radius);
  background:var(--bg-card);border:1px solid var(--border);
  transition:all .3s;position:relative;overflow:hidden;
}
.feature-card::before{
  content:'';position:absolute;top:0;left:0;width:100%;height:3px;
  background:var(--gradient-accent);transform:scaleX(0);transition:transform .3s;
}
.feature-card:hover::before{transform:scaleX(1)}
.feature-card:hover{transform:translateY(-4px);box-shadow:var(--shadow)}
.feature-icon{
  width:56px;height:56px;border-radius:14px;margin-bottom:18px;
  display:flex;align-items:center;justify-content:center;font-size:1.6rem;
  background:rgba(26,115,232,.12);border:1px solid rgba(26,115,232,.2);
}
.feature-card h3{font-size:1.1rem;margin-bottom:8px;color:var(--text-bright)}
.feature-card p{font-size:.88rem;color:var(--text-muted);line-height:1.65}

/* ========== Modules Section (¿¨Æ¬Ä£¿é) ========== */
.modules-grid{
  max-width:1200px;margin:0 auto;display:grid;
  grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:24px;
}
.module-card{
  border-radius:var(--radius-lg);overflow:hidden;
  background:var(--bg-card);border:1px solid var(--border);
  transition:all .3s;
}
.module-card:hover{box-shadow:var(--shadow-glow);transform:scale(1.01)}
.module-card .module-img{
  width:100%;aspect-ratio:16/9;display:flex;align-items:center;justify-content:center;
  font-size:2.5rem;
  background:linear-gradient(135deg,#1a2744,#0f2847,#1a365d);
}
.module-card .module-body{padding:24px}
.module-card .module-body h3{font-size:1.1rem;margin-bottom:10px;color:var(--text-bright)}
.module-card .module-body p{font-size:.88rem;color:var(--text-muted);margin-bottom:16px}
.module-card .tag-row{display:flex;flex-wrap:wrap;gap:8px}
.module-card .tag{
  padding:4px 12px;border-radius:20px;font-size:.75rem;
  background:rgba(26,115,232,.1);color:var(--primary);border:1px solid rgba(26,115,232,.2);
}

/* ========== Download Section ========== */
.download-section{
  background:linear-gradient(135deg,rgba(26,115,232,.08),rgba(0,229,255,.05));
  border-top:1px solid var(--border);border-bottom:1px solid var(--border);
}
.download-inner{max-width:800px;margin:0 auto;text-align:center}
.download-inner h2{font-size:clamp(1.5rem,3.5vw,2rem);margin-bottom:12px}
.download-inner p{color:var(--text-muted);margin-bottom:32px}
.download-cards{
  display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:20px;
  margin-bottom:32px;
}
.download-card{
  padding:28px 20px;border-radius:var(--radius);
  background:var(--bg-card);border:1px solid var(--border);
  transition:all .3s;
}
.download-card:hover{border-color:var(--primary);transform:translateY(-4px)}
.download-card .os-icon{font-size:2.5rem;margin-bottom:12px}
.download-card h4{font-size:1rem;margin-bottom:6px;color:var(--text-bright)}
.download-card .version{font-size:.8rem;color:var(--text-muted);margin-bottom:16px}
.download-card .btn{width:100%;justify-content:center;padding:12px;font-size:.9rem}

/* ========== Tutorial Section ========== */
.tutorial-steps{
  max-width:900px;margin:0 auto;
  display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:24px;
}
.step-card{
  text-align:center;padding:32px 24px;border-radius:var(--radius);
  background:var(--bg-card);border:1px solid var(--border);position:relative;
}
.step-card .step-num{
  width:44px;height:44px;border-radius:50%;margin:0 auto 16px;
  display:flex;align-items:center;justify-content:center;
  font-size:1.2rem;font-weight:800;color:#fff;
  background:var(--gradient-btn);
}
.step-card h4{font-size:1rem;margin-bottom:8px;color:var(--text-bright)}
.step-card p{font-size:.85rem;color:var(--text-muted)}

/* ========== FAQ Section ========== */
.faq-list{max-width:900px;margin:0 auto;display:flex;flex-direction:column;gap:12px}
.faq-item{
  border-radius:var(--radius);background:var(--bg-card);border:1px solid var(--border);
  overflow:hidden;transition:border-color .3s;
}
.faq-item:hover{border-color:var(--primary)}
.faq-q{
  padding:18px 24px;cursor:pointer;display:flex;justify-content:space-between;
  align-items:center;font-weight:600;font-size:1rem;color:var(--text-bright);
  user-select:none;
}
.faq-q .arrow{font-size:1.2rem;color:var(--text-muted);transition:transform .3s}
.faq-item.open .faq-q .arrow{transform:rotate(180deg)}
.faq-a{
  max-height:0;overflow:hidden;transition:max-height .35s ease,padding .35s ease;
  padding:0 24px;
}
.faq-item.open .faq-a{max-height:400px;padding:0 24px 20px}
.faq-a p{font-size:.9rem;color:var(--text-muted);line-height:1.7}

/* ========== Stats Section ========== */
.stats-grid{
  max-width:1000px;margin:0 auto;display:grid;
  grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:20px;
}
.stat-card{
  text-align:center;padding:32px 20px;border-radius:var(--radius);
  background:var(--bg-card);border:1px solid var(--border);
}
.stat-card .stat-num{
  font-size:clamp(1.8rem,4vw,2.5rem);font-weight:900;
  background:linear-gradient(135deg,var(--accent),var(--primary));
  -webkit-background-clip:text;-webkit-text-fill-color:transparent;
}
.stat-card .stat-label{font-size:.88rem;color:var(--text-muted);margin-top:6px}

/* ========== Footer ========== */
.footer{
  background:rgba(0,0,0,.4);border-top:1px solid var(--border);padding:48px 24px 24px;
}
.footer-inner{max-width:1200px;margin:0 auto}
.footer-top{
  display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:40px;
  margin-bottom:40px;
}
.footer-col h4{font-size:1rem;margin-bottom:14px;color:var(--text-bright)}
.footer-col ul li{margin-bottom:8px}
.footer-col ul a{font-size:.88rem;color:var(--text-muted)}
.footer-col ul a:hover{color:var(--accent)}
.footer-col p{font-size:.85rem;color:var(--text-muted);line-height:1.7}
.footer-bottom{
  text-align:center;padding-top:24px;border-top:1px solid var(--border);
  font-size:.82rem;color:var(--text-muted);
}

/* ========== Back to Top ========== */
.back-top{
  position:fixed;bottom:28px;right:28px;width:48px;height:48px;
  border-radius:50%;display:flex;align-items:center;justify-content:center;
  font-size:1.3rem;cursor:pointer;z-index:999;
  background:var(--gradient-btn);color:#fff;border:none;box-shadow:var(--shadow);
  opacity:0;visibility:hidden;transform:translateY(12px);transition:all .3s;
}
.back-top.show{opacity:1;visibility:visible;transform:translateY(0)}
.back-top:hover{transform:translateY(-3px);box-shadow:var(--shadow-glow)}

/* ========== Responsive ========== */
@media(max-width:768px){
  .navbar nav{display:none;position:absolute;top:64px;left:0;width:100%;
    background:rgba(10,14,26,.97);backdrop-filter:blur(16px);
    border-bottom:1px solid var(--border);padding:12px 24px;
  }
  .navbar nav.open{display:block}
  .navbar nav ul{flex-direction:column;gap:4px}
  .navbar nav a{display:block;padding:10px 16px}
  .mobile-menu-btn{display:block}
  .hero{padding:100px 16px 60px}
  .section{padding:60px 16px}
  .hero-buttons{flex-direction:column;align-items:center}
  .btn{width:100%;max-width:300px;justify-content:center}
  .showcase-grid,.features-grid,.modules-grid,.tutorial-steps{gap:16px}
}

@media(max-width:480px){
  .navbar .logo span{display:none}
  .stat-card{padding:24px 12px}
}

/* ========== Animations ========== */
.fade-in{opacity:0;transform:translateY(30px);transition:opacity .6s,transform .6s}
.fade-in.visible{opacity:1;transform:translateY(0)}