/* ===== Reset & Base ===== */
*,*::before,*::after{margin:0;padding:0;box-sizing:border-box}
:root{
  --primary:#2563eb;--primary-light:#3b82f6;--primary-dark:#1d4ed8;
  --accent:#f59e0b;--accent-light:#fbbf24;
  --bg:#f8fafc;--bg-dark:#0f172a;--bg-card:#ffffff;
  --text:#1e293b;--text-light:#64748b;--text-white:#f1f5f9;
  --border:#e2e8f0;--shadow:0 4px 24px rgba(0,0,0,.08);
  --radius:16px;--radius-sm:10px;
  --gradient-1:linear-gradient(135deg,#2563eb 0%,#7c3aed 100%);
  --gradient-2:linear-gradient(135deg,#f59e0b 0%,#ef4444 100%);
  --gradient-3:linear-gradient(135deg,#10b981 0%,#06b6d4 100%);
  --gradient-4:linear-gradient(135deg,#8b5cf6 0%,#ec4899 100%);
}
html{scroll-behavior:smooth;font-size:16px}
body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;color:var(--text);background:var(--bg);line-height:1.7;overflow-x:hidden}
a{color:var(--primary);text-decoration:none}
img{max-width:100%;display:block}

/* ===== Utility ===== */
.container{max-width:1200px;margin:0 auto;padding:0 24px}
.section-label{display:inline-flex;align-items:center;gap:8px;font-size:.8rem;font-weight:700;letter-spacing:1px;text-transform:uppercase;padding:6px 16px;border-radius:999px;margin-bottom:16px}
.section-title{font-size:clamp(1.75rem,4vw,2.5rem);font-weight:800;line-height:1.25;margin-bottom:16px;color:var(--text)}
.section-desc{font-size:1.05rem;color:var(--text-light);max-width:680px;margin-bottom:40px}

/* ===== Animations ===== */
@keyframes fadeUp{from{opacity:0;transform:translateY(40px)}to{opacity:1;transform:translateY(0)}}
@keyframes pulse-ring{0%{transform:scale(1);opacity:.6}100%{transform:scale(1.6);opacity:0}}
.animate-in{opacity:0;transform:translateY(40px);transition:opacity .7s ease,transform .7s ease}
.animate-in.visible{opacity:1;transform:translateY(0)}

/* ===== Header / Nav ===== */
.navbar{position:fixed;top:0;left:0;right:0;z-index:100;background:rgba(255,255,255,.85);backdrop-filter:blur(16px);border-bottom:1px solid var(--border);transition:box-shadow .3s}
.navbar.scrolled{box-shadow:0 2px 20px rgba(0,0,0,.08)}
.nav-inner{display:flex;align-items:center;justify-content:space-between;height:64px}
.nav-logo{display:flex;align-items:center;gap:10px;font-weight:800;font-size:1.15rem;color:var(--primary-dark)}
.nav-logo .logo-icon{width:36px;height:36px;background:var(--gradient-1);border-radius:10px;display:flex;align-items:center;justify-content:center;color:#fff;font-size:1.1rem;font-weight:900}
.nav-links{display:flex;gap:8px;align-items:center}
.nav-links a{padding:8px 16px;border-radius:8px;font-size:.9rem;font-weight:500;color:var(--text);transition:background .2s,color .2s}
.nav-links a:hover{background:var(--primary);color:#fff}
.nav-download{display:inline-flex;align-items:center;gap:6px;padding:8px 20px;border-radius:8px;font-size:.9rem;font-weight:600;background:var(--gradient-1);color:#fff;transition:opacity .2s,transform .2s}
.nav-download:hover{opacity:.9;transform:translateY(-1px)}

/* ===== Hero ===== */
.hero{position:relative;padding:160px 0 100px;overflow:hidden;background:var(--bg-dark);text-align:center}
.hero::before{content:'';position:absolute;inset:0;background:var(--gradient-1);opacity:.9;z-index:1}
.hero::after{content:'';position:absolute;bottom:-2px;left:0;right:0;height:120px;background:var(--bg);z-index:2;clip-path:polygon(0 60%,100% 0,100% 100%,0 100%)}
.hero-content{position:relative;z-index:3;max-width:800px;margin:0 auto;padding:0 24px}
.hero-badge{display:inline-flex;align-items:center;gap:8px;background:rgba(255,255,255,.15);border:1px solid rgba(255,255,255,.25);border-radius:999px;padding:8px 20px;font-size:.85rem;color:rgba(255,255,255,.9);margin-bottom:32px;animation:fadeUp .8s ease forwards;backdrop-filter:blur(8px)}
.hero-badge .dot{width:8px;height:8px;background:#4ade80;border-radius:50%;animation:pulse-ring 2s infinite}
.hero h1{font-size:clamp(2.4rem,6vw,4rem);font-weight:900;color:#fff;line-height:1.15;margin-bottom:24px;animation:fadeUp .8s .15s ease both}
.hero h1 span{background:linear-gradient(90deg,#fbbf24,#f97316);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}
.hero-sub{font-size:clamp(1rem,2.5vw,1.25rem);color:rgba(255,255,255,.8);margin-bottom:48px;animation:fadeUp .8s .3s ease both;max-width:600px;margin-left:auto;margin-right:auto}
.hero-actions{display:flex;gap:16px;justify-content:center;flex-wrap:wrap;animation:fadeUp .8s .45s ease both}
.btn{display:inline-flex;align-items:center;gap:8px;padding:14px 32px;border-radius:12px;font-size:1rem;font-weight:600;border:none;cursor:pointer;transition:transform .2s,box-shadow .2s}
.btn:hover{transform:translateY(-2px)}
.btn-primary{background:#fff;color:var(--primary-dark);box-shadow:0 4px 24px rgba(0,0,0,.15)}
.btn-primary:hover{box-shadow:0 8px 32px rgba(0,0,0,.2)}
.btn-download{background:linear-gradient(135deg,#f59e0b,#f97316);color:#fff;box-shadow:0 4px 24px rgba(245,158,11,.35);font-size:1.05rem;padding:16px 36px}
.btn-download:hover{box-shadow:0 8px 32px rgba(245,158,11,.45)}
.btn-outline{background:transparent;color:#fff;border:2px solid rgba(255,255,255,.4)}
.btn-outline:hover{background:rgba(255,255,255,.1);border-color:rgba(255,255,255,.7)}
.hero-features{display:flex;gap:40px;justify-content:center;margin-top:64px;animation:fadeUp .8s .6s ease both}
.hero-feat{text-align:center;color:rgba(255,255,255,.85)}
.hero-feat .num{font-size:2.2rem;font-weight:900;color:#fff;display:block}
.hero-feat .label{font-size:.85rem;margin-top:4px}

/* ===== Stats Bar ===== */
.stats-bar{background:var(--bg-card);border-radius:var(--radius);box-shadow:var(--shadow);margin:-60px auto 0;position:relative;z-index:5;display:grid;grid-template-columns:repeat(4,1fr);gap:1px;overflow:hidden;max-width:960px}
.stat-item{padding:32px 24px;text-align:center;position:relative}
.stat-item:not(:last-child)::after{content:'';position:absolute;right:0;top:20%;height:60%;width:1px;background:var(--border)}
.stat-icon{width:48px;height:48px;border-radius:12px;display:flex;align-items:center;justify-content:center;margin:0 auto 12px;font-size:1.4rem}
.stat-num{font-size:1.8rem;font-weight:800;color:var(--text);line-height:1.2}
.stat-label{font-size:.85rem;color:var(--text-light);margin-top:4px}

/* ===== Features Overview ===== */
.overview{padding:100px 0}
.overview-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:24px;margin-top:48px}
.overview-card{background:var(--bg-card);border-radius:var(--radius);padding:36px 28px;border:1px solid var(--border);transition:transform .3s,box-shadow .3s;position:relative;overflow:hidden}
.overview-card:hover{transform:translateY(-6px);box-shadow:0 12px 40px rgba(0,0,0,.1)}
.overview-card::before{content:'';position:absolute;top:0;left:0;right:0;height:4px}
.overview-card:nth-child(1)::before{background:var(--gradient-1)}
.overview-card:nth-child(2)::before{background:var(--gradient-2)}
.overview-card:nth-child(3)::before{background:var(--gradient-3)}
.overview-card:nth-child(4)::before{background:var(--gradient-4)}
.overview-icon{width:56px;height:56px;border-radius:14px;display:flex;align-items:center;justify-content:center;font-size:1.6rem;margin-bottom:20px}
.overview-card:nth-child(1) .overview-icon{background:rgba(37,99,235,.1);color:var(--primary)}
.overview-card:nth-child(2) .overview-icon{background:rgba(245,158,11,.1);color:var(--accent)}
.overview-card:nth-child(3) .overview-icon{background:rgba(16,185,129,.1);color:#10b981}
.overview-card:nth-child(4) .overview-icon{background:rgba(139,92,246,.1);color:#8b5cf6}
.overview-card h3{font-size:1.15rem;font-weight:700;margin-bottom:10px}
.overview-card p{font-size:.9rem;color:var(--text-light);line-height:1.6}
.overview-card .card-link{display:inline-flex;align-items:center;gap:6px;margin-top:16px;font-size:.9rem;font-weight:600;color:var(--primary);transition:gap .2s}
.overview-card:hover .card-link{gap:10px}

/* ===== Feature Detail Sections ===== */
.feature-section{padding:80px 0}
.feature-section:nth-child(even){background:#f1f5f9}
.feature-layout{display:grid;grid-template-columns:1fr 1fr;gap:60px;align-items:start}
.feature-section:nth-child(even) .feature-layout{direction:rtl}
.feature-section:nth-child(even) .feature-layout>*{direction:ltr}
.feature-visual{position:relative;border-radius:var(--radius);overflow:hidden;background:var(--bg-dark);padding:40px;min-height:420px;display:flex;align-items:center;justify-content:center}
.feature-visual-inner{width:100%;position:relative;z-index:1}

/* Mock UI inside visual */
.mock-window{background:var(--bg-card);border-radius:var(--radius-sm);box-shadow:0 20px 60px rgba(0,0,0,.3);overflow:hidden;width:100%;max-width:440px}
.mock-titlebar{display:flex;align-items:center;gap:8px;padding:12px 16px;background:#f1f5f9;border-bottom:1px solid var(--border)}
.mock-dot{width:10px;height:10px;border-radius:50%}
.mock-dot.r{background:#ef4444}.mock-dot.y{background:#f59e0b}.mock-dot.g{background:#22c55e}
.mock-body{padding:16px}
.mock-row{display:flex;align-items:center;gap:10px;padding:8px 0;border-bottom:1px solid var(--border);font-size:.8rem}
.mock-row:last-child{border-bottom:none}
.mock-tag{display:inline-flex;padding:3px 10px;border-radius:6px;font-size:.7rem;font-weight:600}
.mock-input{background:#f1f5f9;border:1px solid var(--border);border-radius:6px;padding:6px 12px;font-size:.8rem;flex:1;color:var(--text)}
.mock-btn{padding:6px 16px;border-radius:6px;border:none;font-size:.75rem;font-weight:600;color:#fff;cursor:pointer}
.mock-highlight{background:rgba(37,99,235,.08);border-left:3px solid var(--primary);padding:10px 14px;border-radius:0 8px 8px 0;margin:8px 0;font-size:.8rem}

.feature-info h2{font-size:clamp(1.5rem,3vw,2rem);font-weight:800;margin-bottom:20px}
.feature-info .section-label{margin-bottom:16px}
.feature-desc{font-size:1rem;color:var(--text-light);margin-bottom:32px;line-height:1.8}

/* Sub feature cards */
.sub-features{display:grid;grid-template-columns:1fr;gap:12px}
.sub-feat-card{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius-sm);padding:20px;transition:border-color .2s,box-shadow .2s}
.sub-feat-card:hover{border-color:var(--primary);box-shadow:0 4px 16px rgba(37,99,235,.08)}
.sub-feat-card .sf-header{display:flex;align-items:center;gap:10px;margin-bottom:8px}
.sub-feat-card .sf-icon{width:32px;height:32px;border-radius:8px;display:flex;align-items:center;justify-content:center;font-size:.9rem;flex-shrink:0}
.sub-feat-card h4{font-size:.95rem;font-weight:700}
.sub-feat-card p{font-size:.82rem;color:var(--text-light);line-height:1.65;padding-left:42px}
.sub-feat-card ul{list-style:none;padding-left:42px;margin-top:6px}
.sub-feat-card ul li{font-size:.82rem;color:var(--text-light);line-height:1.7;padding-left:16px;position:relative}
.sub-feat-card ul li::before{content:'';position:absolute;left:0;top:9px;width:6px;height:6px;border-radius:50%;background:var(--primary);opacity:.5}

/* Visual decoration */
.deco-circle{position:absolute;border-radius:50%;opacity:.15;pointer-events:none}
.feature-visual .deco-circle.c1{width:200px;height:200px;top:-40px;right:-40px}
.feature-visual .deco-circle.c2{width:140px;height:140px;bottom:-30px;left:-30px}

/* ===== Feature 1 ===== */
.f1 .section-label{background:rgba(37,99,235,.1);color:var(--primary)}
.f1 .sf-icon{background:rgba(37,99,235,.1);color:var(--primary)}
.f1 .feature-visual .deco-circle{background:var(--primary)}

/* ===== Feature 2 ===== */
.f2 .section-label{background:rgba(245,158,11,.1);color:var(--accent)}
.f2 .sf-icon{background:rgba(245,158,11,.1);color:var(--accent)}
.f2 .feature-visual .deco-circle{background:var(--accent)}

/* ===== Feature 3 ===== */
.f3 .section-label{background:rgba(16,185,129,.1);color:#10b981}
.f3 .sf-icon{background:rgba(16,185,129,.1);color:#10b981}
.f3 .feature-visual .deco-circle{background:#10b981}

/* ===== Feature 4 ===== */
.f4 .section-label{background:rgba(139,92,246,.1);color:#8b5cf6}
.f4 .sf-icon{background:rgba(139,92,246,.1);color:#8b5cf6}
.f4 .feature-visual .deco-circle{background:#8b5cf6}

/* ===== Toolbox Grid ===== */
.toolbox-grid{display:grid;grid-template-columns:1fr 1fr;gap:16px}
.toolbox-item{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius-sm);padding:24px;transition:transform .2s,box-shadow .2s,border-color .2s}
.toolbox-item:hover{transform:translateY(-3px);box-shadow:0 8px 24px rgba(0,0,0,.08);border-color:#10b981}
.toolbox-item .tb-icon{width:40px;height:40px;border-radius:10px;display:flex;align-items:center;justify-content:center;font-size:1.1rem;margin-bottom:12px;background:rgba(16,185,129,.1);color:#10b981}
.toolbox-item h4{font-size:.95rem;font-weight:700;margin-bottom:8px}
.toolbox-item p{font-size:.82rem;color:var(--text-light);line-height:1.65}
.toolbox-item ul{list-style:none;margin-top:8px}
.toolbox-item ul li{font-size:.8rem;color:var(--text-light);line-height:1.7;padding-left:14px;position:relative}
.toolbox-item ul li::before{content:'';position:absolute;left:0;top:9px;width:5px;height:5px;border-radius:50%;background:#10b981;opacity:.5}

/* ===== Clean Steps ===== */
.clean-steps{display:flex;flex-direction:column;gap:20px}
.clean-step{display:flex;gap:16px;align-items:flex-start}
.clean-step-num{width:36px;height:36px;border-radius:10px;display:flex;align-items:center;justify-content:center;font-size:.85rem;font-weight:800;color:#fff;background:var(--gradient-4);flex-shrink:0}
.clean-step h4{font-size:.95rem;font-weight:700;margin-bottom:4px}
.clean-step p{font-size:.85rem;color:var(--text-light);line-height:1.65}

/* ===== CTA ===== */
.cta{padding:100px 0;text-align:center;background:var(--bg-dark);position:relative;overflow:hidden}
.cta::before{content:'';position:absolute;inset:0;background:var(--gradient-1);opacity:.9}
.cta-content{position:relative;z-index:1}
.cta h2{font-size:clamp(1.75rem,4vw,2.5rem);font-weight:800;color:#fff;margin-bottom:16px}
.cta p{color:rgba(255,255,255,.8);font-size:1.05rem;margin-bottom:40px;max-width:560px;margin-left:auto;margin-right:auto}
.cta .btn-download{font-size:1.15rem;padding:18px 48px}

/* ===== Footer ===== */
.footer{padding:40px 0;text-align:center;color:var(--text-light);font-size:.85rem;background:var(--bg-dark);border-top:1px solid rgba(255,255,255,.05)}
.footer-inner{display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:16px}
.footer a{color:var(--primary-light);transition:color .2s}
.footer a:hover{color:#fff}

/* ===== Responsive ===== */
@media(max-width:1024px){
  .overview-grid{grid-template-columns:repeat(2,1fr)}
  .feature-layout{grid-template-columns:1fr;gap:40px}
  .feature-section:nth-child(even) .feature-layout{direction:ltr}
  .feature-visual{min-height:320px}
  .stats-bar{grid-template-columns:repeat(2,1fr);max-width:600px}
  .stat-item:nth-child(2)::after{display:none}
}
@media(max-width:768px){
  .nav-links a:not(.nav-download){display:none}
  .hero{padding:120px 0 80px}
  .hero-features{gap:24px;flex-wrap:wrap}
  .overview-grid{grid-template-columns:1fr}
  .stats-bar{grid-template-columns:1fr;margin:-40px auto 0;max-width:360px}
  .stat-item:not(:last-child)::after,.stat-item:nth-child(2)::after{display:none}
  .feature-layout{gap:32px}
  .toolbox-grid{grid-template-columns:1fr}
  .footer-inner{flex-direction:column;text-align:center}
  .extra-row{grid-template-columns:1fr!important}
}

/* ===== Scroll Progress ===== */
.scroll-progress{position:fixed;top:64px;left:0;height:3px;background:var(--gradient-1);z-index:99;transition:width .1s}

/* ===== Back to Top ===== */
.back-top{position:fixed;bottom:32px;right:32px;width:44px;height:44px;border-radius:12px;background:var(--primary);color:#fff;border:none;cursor:pointer;display:flex;align-items:center;justify-content:center;font-size:1.2rem;box-shadow:0 4px 16px rgba(37,99,235,.3);opacity:0;transform:translateY(20px);transition:opacity .3s,transform .3s;z-index:90}
.back-top.show{opacity:1;transform:translateY(0)}
.back-top:hover{background:var(--primary-dark);transform:translateY(-2px)}

/* ===== Tabs ===== */
.tab-group{display:flex;gap:8px;margin-bottom:24px;flex-wrap:wrap;justify-content:center}
.tab-btn{padding:8px 18px;border-radius:8px;border:1px solid var(--border);background:transparent;font-size:.85rem;font-weight:600;color:var(--text-light);cursor:pointer;transition:all .2s}
.tab-btn.active{background:var(--primary);color:#fff;border-color:var(--primary)}
.tab-panel{display:none}
.tab-panel.active{display:grid;grid-template-columns:1fr;gap:12px;animation:fadeUp .4s ease}

/* ===== Extra row grid ===== */
.extra-row{display:grid;gap:20px;margin-top:60px}
.extra-row-3{grid-template-columns:repeat(3,1fr)}
.extra-row-2{grid-template-columns:1fr 1fr}