:root{
  --primary:#2563eb;
  --primary-600:#1d4ed8;
  --primary-700:#1e40af;
  --primary-50:#eff5ff;
  --accent:#0ea5e9;
  --ink:#0f172a;
  --body:#334155;
  --muted:#64748b;
  --line:#e6edf6;
  --soft:#f5f8fd;
  --soft-2:#eef4ff;
  --white:#ffffff;
  --radius:16px;
  --radius-sm:10px;
  --shadow-sm:0 1px 2px rgba(15,23,42,.06),0 1px 3px rgba(15,23,42,.08);
  --shadow:0 10px 30px -12px rgba(30,64,175,.25);
  --shadow-lg:0 24px 60px -20px rgba(30,64,175,.35);
  --container:1180px;
  --font:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{font-family:var(--font);color:var(--body);background:var(--white);line-height:1.7;-webkit-font-smoothing:antialiased}
a{color:inherit;text-decoration:none}
img{max-width:100%;display:block}
.container{max-width:var(--container);margin:0 auto;padding:0 22px}
.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0,0,0,0)}
.text-primary{color:var(--primary)}
.muted{color:var(--muted)}

/* ---------- buttons ---------- */
.btn{display:inline-flex;align-items:center;gap:8px;padding:13px 26px;border-radius:999px;font-weight:600;font-size:15px;cursor:pointer;border:1.5px solid transparent;transition:.2s ease;white-space:nowrap}
.btn-primary{background:var(--primary);color:#fff;box-shadow:var(--shadow)}
.btn-primary:hover{background:var(--primary-700);transform:translateY(-1px)}
.btn-ghost{background:#fff;color:var(--primary);border-color:var(--line)}
.btn-ghost:hover{border-color:var(--primary);background:var(--primary-50)}
.btn-light{background:#fff;color:var(--primary-700)}
.btn-light:hover{background:var(--soft-2)}

/* ---------- header ---------- */
.site-header{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.85);backdrop-filter:saturate(180%) blur(12px);border-bottom:1px solid var(--line)}
.nav{display:flex;align-items:center;justify-content:space-between;height:68px}
.brand{display:flex;align-items:center;gap:11px;font-weight:800;color:var(--ink);font-size:18px;letter-spacing:.2px}
.brand .logo{width:38px;height:38px;border-radius:11px;background:linear-gradient(135deg,var(--primary),var(--accent));display:grid;place-items:center;color:#fff;flex:none}
.brand small{display:block;font-size:11px;font-weight:500;color:var(--muted);letter-spacing:.5px}
.nav-links{display:flex;align-items:center;gap:30px;list-style:none}
.nav-links a{font-size:15px;color:var(--body);font-weight:500;position:relative;padding:6px 0}
.nav-links a:hover,.nav-links a.active{color:var(--primary)}
.nav-links a.active::after{content:"";position:absolute;left:0;right:0;bottom:-2px;height:2px;border-radius:2px;background:var(--primary)}
.nav-cta{display:flex;align-items:center;gap:12px}
.nav-toggle{display:none;background:none;border:0;cursor:pointer;padding:8px}
.nav-toggle span{display:block;width:22px;height:2px;background:var(--ink);margin:4px 0;border-radius:2px}

/* ---------- hero ---------- */
.hero{position:relative;overflow:hidden;background:linear-gradient(135deg,#0b1f4d 0%,#16307e 55%,#1d4ed8 100%)}
.hero .hero-bg{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;opacity:.5;mix-blend-mode:screen}
.hero::after{content:"";position:absolute;inset:0;background:linear-gradient(90deg,rgba(8,20,52,.92) 0%,rgba(8,20,52,.55) 45%,rgba(8,20,52,.15) 100%)}
.hero-inner{position:relative;z-index:2;padding:84px 0 92px;max-width:680px}
.hero .eyebrow{display:inline-flex;align-items:center;gap:8px;color:#bcd2ff;font-size:13px;font-weight:600;letter-spacing:1px;text-transform:uppercase;background:rgba(255,255,255,.08);border:1px solid rgba(255,255,255,.16);padding:7px 14px;border-radius:999px;margin-bottom:22px}
.hero h1{color:#fff;font-size:44px;line-height:1.25;font-weight:800;letter-spacing:.5px;margin-bottom:18px}
.hero h1 .hl{background:linear-gradient(90deg,#7dd3fc,#38bdf8);-webkit-background-clip:text;background-clip:text;color:transparent}
.hero p.lead{color:#d7e2f7;font-size:18px;margin-bottom:30px;max-width:560px}
.hero-actions{display:flex;gap:14px;flex-wrap:wrap}
.hero-actions .btn-light{background:rgba(255,255,255,.95)}
.hero-stats{display:flex;gap:34px;margin-top:42px;flex-wrap:wrap}
.hero-stats .stat{color:#fff}
.hero-stats .num{font-size:28px;font-weight:800;color:#fff}
.hero-stats .lbl{font-size:13px;color:#a9c0ee}

/* ---------- sections ---------- */
section{padding:76px 0}
.section-head{max-width:680px;margin:0 auto 46px;text-align:center}
.section-head .tag{color:var(--primary);font-weight:700;font-size:14px;letter-spacing:1px;text-transform:uppercase}
.section-head h2{color:var(--ink);font-size:32px;font-weight:800;margin:10px 0 12px;letter-spacing:.3px}
.section-head p{color:var(--muted);font-size:16px}
.bg-soft{background:var(--soft)}

/* ---------- feature grid ---------- */
.grid{display:grid;gap:24px}
.grid-3{grid-template-columns:repeat(3,1fr)}
.grid-2{grid-template-columns:repeat(2,1fr)}
.card{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:30px;transition:.22s ease;box-shadow:var(--shadow-sm)}
.card:hover{transform:translateY(-4px);box-shadow:var(--shadow);border-color:#cfe0ff}
.card .ic{width:50px;height:50px;border-radius:13px;background:var(--primary-50);color:var(--primary);display:grid;place-items:center;margin-bottom:18px}
.card h3{color:var(--ink);font-size:19px;margin-bottom:9px;font-weight:700}
.card p{font-size:15px;color:var(--muted)}

/* ---------- product split ---------- */
.split{display:grid;grid-template-columns:1.05fr .95fr;gap:54px;align-items:center}
.split.reverse{grid-template-columns:.95fr 1.05fr}
.split .copy h2{color:var(--ink);font-size:30px;font-weight:800;margin-bottom:14px}
.split .copy>p{color:var(--muted);font-size:16px;margin-bottom:22px}
.feature-list{list-style:none;display:grid;gap:14px}
.feature-list li{display:flex;gap:12px;align-items:flex-start;font-size:15px;color:var(--body)}
.feature-list .ck{flex:none;width:24px;height:24px;border-radius:7px;background:var(--primary-50);color:var(--primary);display:grid;place-items:center;margin-top:2px}
.visual{position:relative;border-radius:24px;overflow:hidden;box-shadow:var(--shadow-lg);background:linear-gradient(135deg,#eaf1ff,#dbeafe);aspect-ratio:4/5;display:grid;place-items:center}
.visual img{width:78%;border-radius:18px;box-shadow:0 20px 50px -18px rgba(15,23,42,.45)}
.visual .badge{position:absolute;left:18px;bottom:18px;background:#fff;border-radius:14px;padding:12px 16px;box-shadow:var(--shadow);font-size:13px;color:var(--muted);display:flex;gap:10px;align-items:center}
.visual .badge b{color:var(--ink);font-size:15px;display:block}

/* ---------- steps ---------- */
.steps{counter-reset:step;display:grid;grid-template-columns:repeat(4,1fr);gap:22px}
.step{position:relative;background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:28px 24px}
.step::before{counter-increment:step;content:counter(step);position:absolute;top:-16px;left:24px;width:38px;height:38px;border-radius:11px;background:linear-gradient(135deg,var(--primary),var(--accent));color:#fff;font-weight:800;display:grid;place-items:center;box-shadow:var(--shadow)}
.step h4{color:var(--ink);font-size:17px;margin:14px 0 8px;font-weight:700}
.step p{font-size:14px;color:var(--muted)}

/* ---------- stats band ---------- */
.band{background:linear-gradient(135deg,#0b1f4d,#1d4ed8);color:#fff;border-radius:24px;padding:48px;text-align:center}
.band .grid-4{display:grid;grid-template-columns:repeat(4,1fr);gap:20px}
.band .num{font-size:36px;font-weight:800}
.band .lbl{color:#bcd2ff;font-size:14px;margin-top:4px}

/* ---------- faq ---------- */
.faq{display:grid;gap:14px;max-width:820px;margin:0 auto}
.faq details{border:1px solid var(--line);border-radius:var(--radius-sm);background:#fff;padding:0}
.faq summary{cursor:pointer;list-style:none;padding:18px 22px;font-weight:600;color:var(--ink);font-size:16px;display:flex;justify-content:space-between;align-items:center;gap:12px}
.faq summary::-webkit-details-marker{display:none}
.faq summary .plus{flex:none;width:22px;height:22px;position:relative}
.faq summary .plus::before,.faq summary .plus::after{content:"";position:absolute;background:var(--primary);border-radius:2px}
.faq summary .plus::before{top:10px;left:4px;right:4px;height:2px}
.faq summary .plus::after{left:10px;top:4px;bottom:4px;width:2px;transition:.2s}
.faq details[open] summary .plus::after{transform:scaleY(0)}
.faq .ans{padding:0 22px 20px;color:var(--muted);font-size:15px}

/* ---------- cta ---------- */
.cta{background:var(--soft-2);border:1px solid #d7e6ff;border-radius:24px;padding:54px;text-align:center}
.cta h2{color:var(--ink);font-size:30px;font-weight:800;margin-bottom:10px}
.cta p{color:var(--muted);margin-bottom:24px;font-size:16px}

/* ---------- footer ---------- */
.site-footer{background:#0b1530;color:#c5d2ec;padding:56px 0 26px}
.footer-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr 1.2fr;gap:36px}
.site-footer .brand{color:#fff;margin-bottom:14px}
.site-footer p.desc{font-size:14px;color:#9fb0d4;max-width:300px}
.footer-col h5{color:#fff;font-size:15px;margin-bottom:14px;font-weight:700}
.footer-col a{display:block;color:#9fb0d4;font-size:14px;padding:5px 0}
.footer-col a:hover{color:#fff}
.footer-bottom{border-top:1px solid rgba(255,255,255,.1);margin-top:38px;padding-top:20px;display:flex;justify-content:space-between;flex-wrap:wrap;gap:10px;font-size:13px;color:#8497bd}
.footer-bottom a{color:#8497bd}
.footer-bottom a:hover{color:#fff}

/* ---------- contact ---------- */
.contact-grid{display:grid;grid-template-columns:1fr 1fr;gap:40px}
.contact-info .item{display:flex;gap:14px;margin-bottom:20px}
.contact-info .item .ic{width:44px;height:44px;border-radius:12px;background:var(--primary-50);color:var(--primary);display:grid;place-items:center;flex:none}
.contact-info .item b{color:var(--ink);display:block;font-size:15px}
.contact-info .item span{color:var(--muted);font-size:14px}
.form{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:30px;box-shadow:var(--shadow-sm)}
.form label{display:block;font-size:14px;font-weight:600;color:var(--ink);margin-bottom:7px}
.form input,.form textarea{width:100%;padding:12px 14px;border:1px solid var(--line);border-radius:var(--radius-sm);font-size:15px;font-family:inherit;margin-bottom:18px;background:var(--soft);color:var(--body)}
.form input:focus,.form textarea:focus{outline:none;border-color:var(--primary);background:#fff}
.qr-card{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:26px;text-align:center;box-shadow:var(--shadow-sm)}
.qr-card .qr{width:180px;height:180px;margin:0 auto 14px;border-radius:14px;background:repeating-conic-gradient(#0f172a 0% 25%,#fff 0% 50%) 50%/22px 22px;position:relative;display:grid;place-items:center}
.qr-card .qr::after{content:"智能投稿助手";position:absolute;background:#fff;padding:6px 10px;border-radius:8px;font-size:12px;font-weight:700;color:var(--ink);box-shadow:var(--shadow-sm)}

/* ---------- breadcrumb ---------- */
.crumb{padding:18px 0;font-size:13px;color:var(--muted)}
.crumb a:hover{color:var(--primary)}

/* ---------- 404 ---------- */
.nf{text-align:center;padding:120px 0}
.nf h1{font-size:96px;color:var(--primary);font-weight:800}
.nf p{color:var(--muted);margin-bottom:24px}

/* ---------- responsive ---------- */
@media(max-width:980px){
  .grid-3{grid-template-columns:1fr 1fr}
  .steps{grid-template-columns:1fr 1fr}
  .split,.split.reverse{grid-template-columns:1fr;gap:32px}
  .footer-grid{grid-template-columns:1fr 1fr}
  .band .grid-4{grid-template-columns:1fr 1fr}
  .contact-grid{grid-template-columns:1fr}
}
@media(max-width:760px){
  .nav-links{display:none}
  .nav-toggle{display:block}
  .nav-links.open{display:flex;position:absolute;top:68px;left:0;right:0;flex-direction:column;background:#fff;padding:18px 22px;gap:6px;border-bottom:1px solid var(--line);box-shadow:var(--shadow)}
  .nav-links.open a{padding:10px 0}
  .nav-cta .btn-ghost{display:none}
  .hero-inner{padding:60px 0 70px}
  .hero h1{font-size:32px}
  .hero p.lead{font-size:16px}
  .section-head h2{font-size:26px}
  .grid-3,.steps,.band .grid-4,.footer-grid{grid-template-columns:1fr}
  section{padding:56px 0}
  .cta,.band{padding:36px 22px}
}