/* Set-C · 极简白 SaaS */
* { margin:0; padding:0; box-sizing:border-box; }
:root {
  --ink:#0f172a; --sub:#64748b; --line:#e2e8f0;
  --bg:#ffffff; --bg-soft:#f8fafc;
  --accent:#111827; --accent-soft:#f1f5f9;
  --ring:rgba(15,23,42,.08);
  --radius:14px;
  --sans: "Inter", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
}
html,body {
  background:var(--bg); color:var(--ink);
  font-family:var(--sans); line-height:1.65;
  -webkit-font-smoothing:antialiased;
}
a { color:inherit; text-decoration:none; }
img { max-width:100%; display:block; }

/* 顶栏：极简单行 */
.nav-c {
  position:sticky; top:0; z-index:10;
  background:rgba(255,255,255,.85);
  backdrop-filter: blur(12px);
  border-bottom:1px solid var(--line);
}
.nav-c .row {
  max-width:1200px; margin:0 auto;
  display:flex; align-items:center; justify-content:space-between;
  height:64px; padding:0 24px;
}
.nav-c .brand { display:flex; align-items:center; gap:10px; font-weight:700; font-size:16px; }
.nav-c .brand img { width:28px; height:28px; border-radius:6px; }
.nav-c ul { display:flex; gap:6px; list-style:none; }
.nav-c a {
  padding:7px 14px; border-radius:8px;
  color:var(--sub); font-size:14px; font-weight:500;
}
.nav-c a:hover, .nav-c a.active { color:var(--ink); background:var(--accent-soft); }
.nav-c .cta {
  background:var(--ink); color:#fff !important;
  padding:8px 18px; border-radius:8px;
}
.nav-c .cta:hover { background:#1f2937; }

/* 容器 */
.wrap-c { max-width:1200px; margin:0 auto; padding:80px 24px; }

/* 首屏 */
.hero-c {
  display:grid; grid-template-columns:1.05fr 1fr; gap:60px;
  align-items:center;
}
.hero-c h1 {
  font-size:62px; font-weight:800;
  letter-spacing:-.02em; line-height:1.05;
  margin-bottom:20px;
}
.hero-c h1 .accent { color:var(--sub); font-weight:600; }
.hero-c p.lead {
  font-size:18px; color:var(--sub);
  max-width:480px; margin-bottom:32px;
}
.hero-c .ctas { display:flex; gap:12px; }
.hero-c .ctas .btn-c, .hero-c .ctas .btn-c.ghost { font-size:15px; padding:14px 28px; }
.hero-c .visual {
  background: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
  border-radius:24px; padding:24px;
  box-shadow: 0 30px 60px var(--ring);
}
.hero-c .visual img {
  border-radius:14px;
  box-shadow: 0 12px 24px var(--ring);
}

/* 按钮 */
.btn-c {
  display:inline-flex; align-items:center; gap:6px;
  padding:11px 22px; border-radius:10px;
  background:var(--ink); color:#fff; font-weight:600;
  font-size:14px; transition:.2s;
}
.btn-c:hover { background:#1f2937; transform:translateY(-1px); }
.btn-c.ghost {
  background:transparent; color:var(--ink);
  border:1px solid var(--line);
}
.btn-c.ghost:hover { background:var(--accent-soft); }

/* Logo 墙 */
.trust {
  margin-top:64px; padding:24px 0;
  border-top:1px solid var(--line); border-bottom:1px solid var(--line);
}
.trust .label { text-align:center; color:var(--sub); font-size:12px; text-transform:uppercase; letter-spacing:2px; margin-bottom:14px; }
.trust .logos { display:flex; justify-content:space-around; flex-wrap:wrap; gap:24px; color:var(--sub); font-weight:700; opacity:.7; }
.trust .logos span { font-size:18px; }

/* 章节 */
.section-c { padding:96px 24px; max-width:1200px; margin:0 auto; }
.section-c h2 {
  font-size:40px; font-weight:800; letter-spacing:-.01em;
  margin-bottom:12px;
}
.section-c .sub-c { color:var(--sub); font-size:17px; max-width:560px; margin-bottom:48px; }

/* 功能 grid */
.feat-c { display:grid; grid-template-columns:repeat(3,1fr); gap:24px; }
.feat-c .f {
  padding:28px;
  background:#fff; border:1px solid var(--line);
  border-radius:var(--radius);
  transition:.2s;
}
.feat-c .f:hover {
  border-color:#cbd5e1;
  box-shadow:0 12px 30px var(--ring);
  transform:translateY(-3px);
}
.feat-c .f .ico {
  width:44px; height:44px; border-radius:10px;
  background:var(--accent-soft);
  display:flex; align-items:center; justify-content:center;
  font-size:20px; margin-bottom:16px;
}
.feat-c .f h3 { font-size:18px; margin-bottom:6px; }
.feat-c .f p { color:var(--sub); font-size:14px; }

/* 步骤 */
.steps-c {
  display:grid; grid-template-columns:repeat(4,1fr); gap:24px;
  counter-reset:sc;
}
.steps-c .s {
  background:var(--bg-soft); border-radius:var(--radius);
  padding:24px; position:relative;
}
.steps-c .s::before {
  counter-increment:sc; content:counter(sc, decimal-leading-zero);
  position:absolute; top:18px; right:20px;
  font-size:36px; font-weight:800; color:#cbd5e1;
}
.steps-c .s h4 { font-size:16px; margin-bottom:6px; }
.steps-c .s p { color:var(--sub); font-size:14px; }
.steps-c .s .pill {
  display:inline-block; margin-top:10px;
  background:var(--ink); color:#fff;
  font-size:11px; padding:3px 8px; border-radius:6px;
}

/* 系统要求 */
.req-c { display:grid; grid-template-columns:repeat(3,1fr); gap:20px; }
.req-c .r {
  background:#fff; border:1px solid var(--line);
  border-radius:var(--radius); padding:24px;
}
.req-c .r .head {
  display:flex; align-items:center; justify-content:space-between;
  margin-bottom:14px;
}
.req-c .r h3 { font-size:18px; }
.req-c .r .pill {
  background:var(--accent-soft); color:var(--ink);
  font-size:11px; padding:3px 10px; border-radius:999px; font-weight:600;
}
.req-c .r ul { list-style:none; }
.req-c .r li {
  display:flex; justify-content:space-between;
  padding:10px 0; border-bottom:1px dashed var(--line);
  font-size:13px;
}
.req-c .r li:last-child { border-bottom:0; }
.req-c .r li span:first-child { color:var(--sub); }
.req-c .r li span:last-child { font-weight:600; text-align:right; max-width:60%; }

/* FAQ */
.faq-c details {
  border-bottom:1px solid var(--line);
  padding:22px 0;
}
.faq-c summary {
  cursor:pointer; list-style:none;
  display:flex; justify-content:space-between; align-items:center;
  font-weight:600; font-size:17px;
}
.faq-c summary::after { content:"+"; font-size:24px; font-weight:300; transition:.2s; }
.faq-c details[open] summary::after { transform:rotate(45deg); }
.faq-c p { color:var(--sub); padding-top:10px; max-width:760px; }

/* 下载卡 */
.dl-c { display:grid; grid-template-columns:repeat(3,1fr); gap:24px; }
.dl-c .card {
  border:1px solid var(--line); border-radius:var(--radius);
  overflow:hidden; display:flex; flex-direction:column;
  transition:.2s;
}
.dl-c .card:hover {
  border-color:#cbd5e1;
  box-shadow:0 16px 40px var(--ring);
  transform:translateY(-4px);
}
.dl-c .thumb { aspect-ratio:16/10; object-fit:cover; width:100%; }
.dl-c .body { padding:24px; flex:1; display:flex; flex-direction:column; }
.dl-c .tag {
  align-self:flex-start; font-size:11px; font-weight:700;
  background:var(--accent-soft); color:var(--ink);
  padding:4px 10px; border-radius:6px; margin-bottom:10px;
}
.dl-c h3 { font-size:20px; margin-bottom:6px; }
.dl-c .ver { color:var(--sub); font-size:13px; margin-bottom:14px; }
.dl-c p { color:var(--sub); font-size:14px; flex:1; margin-bottom:18px; }
.dl-c .meta {
  display:flex; justify-content:space-between;
  padding-top:14px; border-top:1px solid var(--line);
  margin-bottom:16px; font-size:12px; color:var(--sub);
}

/* 404 */
.err-c {
  text-align:center; padding:120px 24px;
  max-width:600px; margin:0 auto;
}
.err-c .code {
  font-size:140px; font-weight:800; color:var(--ink);
  line-height:1; letter-spacing:-.04em;
}
.err-c h1 { font-size:28px; margin:16px 0 12px; }
.err-c p { color:var(--sub); margin-bottom:32px; }

/* 页脚 */
.foot-c {
  border-top:1px solid var(--line);
  padding:40px 24px; text-align:center;
  color:var(--sub); font-size:13px;
}
.foot-c .row { max-width:1200px; margin:0 auto; display:flex; justify-content:space-between; flex-wrap:wrap; gap:16px; }
.foot-c a { color:var(--ink); font-weight:600; }

@media (max-width:900px) {
  .hero-c { grid-template-columns:1fr; padding:40px 0; }
  .hero-c h1 { font-size:42px; }
  .feat-c, .steps-c, .req-c, .dl-c { grid-template-columns:1fr; }
  .section-c h2 { font-size:30px; }
  .wrap-c { padding:60px 24px; }
}