:root {
  --bg: #ffffff;
  --bg-soft: #f5f7fc;
  --bg-card: #ffffff;
  --text: #16182b;
  --text-soft: #5b6076;
  --text-faint: #9aa0b4;
  --primary: #6d5efc;
  --primary-2: #00c2ff;
  --primary-grad: linear-gradient(135deg, #6d5efc 0%, #00c2ff 100%);
  --border: #e9ebf4;
  --border-strong: #d8dbea;
  --radius: 18px;
  --radius-sm: 12px;
  --shadow-sm: 0 4px 16px rgba(40, 44, 90, 0.06);
  --shadow: 0 14px 44px rgba(40, 44, 90, 0.10);
  --shadow-lg: 0 24px 70px rgba(60, 50, 160, 0.16);
  --maxw: 1140px;
  --nav-h: 64px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }

.container { max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }

/* ---------- Nav ---------- */
.nav {
  position: sticky; top: 0; z-index: 100;
  height: var(--nav-h);
  background: rgba(255, 255, 255, 0.82);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid var(--border);
}
.nav-inner { height: 100%; display: flex; align-items: center; justify-content: space-between; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 18px; }
.brand .logo {
  width: 30px; height: 30px; border-radius: 9px; background: var(--primary-grad);
  display: grid; place-items: center; color: #fff; font-size: 15px; font-weight: 800;
  box-shadow: 0 4px 12px rgba(109, 94, 252, 0.4);
}
.nav-links { display: flex; align-items: center; gap: 30px; }
.nav-links a { color: var(--text-soft); font-size: 15px; transition: color .2s; }
.nav-links a:hover { color: var(--text); }
.nav-cta {
  padding: 8px 18px; border-radius: 999px; background: var(--primary-grad);
  color: #fff !important; font-size: 14px; font-weight: 600;
  box-shadow: 0 6px 18px rgba(109, 94, 252, 0.35); transition: transform .15s, box-shadow .2s;
}
.nav-cta:hover { transform: translateY(-1px); box-shadow: 0 10px 24px rgba(109, 94, 252, 0.45); }
@media (max-width: 720px) { .nav-links a:not(.nav-cta) { display: none; } }

/* ---------- Hero ---------- */
.hero { position: relative; overflow: hidden; padding: 84px 0 64px; text-align: center; }
.hero::before {
  content: ""; position: absolute; inset: 0; z-index: 0;
  background:
    radial-gradient(620px 360px at 18% 8%, rgba(109, 94, 252, 0.16), transparent 70%),
    radial-gradient(560px 340px at 86% 22%, rgba(0, 194, 255, 0.14), transparent 70%);
}
.hero .container { position: relative; z-index: 1; }
.eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 6px 14px; border-radius: 999px; background: var(--bg-soft);
  border: 1px solid var(--border); color: var(--text-soft); font-size: 13px; margin-bottom: 22px;
}
.eyebrow .dot { width: 7px; height: 7px; border-radius: 50%; background: #25c26e; box-shadow: 0 0 0 3px rgba(37,194,110,.18); }
.hero h1 {
  font-size: clamp(36px, 6vw, 60px); line-height: 1.08; letter-spacing: -0.02em; font-weight: 800;
  background: linear-gradient(120deg, #1a1c34 0%, #4a3fd6 55%, #0099d6 100%);
  -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent;
}
.hero .sub { margin: 20px auto 0; max-width: 640px; font-size: clamp(16px, 2.2vw, 19px); color: var(--text-soft); }
.hero-actions { margin-top: 34px; display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }
.btn {
  display: inline-flex; align-items: center; gap: 9px; padding: 13px 26px; border-radius: 999px;
  font-size: 15px; font-weight: 600; cursor: pointer; border: 1px solid transparent; transition: transform .15s, box-shadow .2s, background .2s;
}
.btn-primary { background: var(--primary-grad); color: #fff; box-shadow: 0 10px 26px rgba(109, 94, 252, 0.38); }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 16px 34px rgba(109, 94, 252, 0.46); }
.btn-ghost { background: var(--bg-soft); color: var(--text); border-color: var(--border); }
.btn-ghost:hover { transform: translateY(-2px); border-color: var(--border-strong); }
.hero-meta { margin-top: 18px; font-size: 13px; color: var(--text-faint); }

/* ---------- Section ---------- */
.section { padding: 64px 0; }
.section-soft { background: var(--bg-soft); }
.section-head { text-align: center; max-width: 620px; margin: 0 auto 44px; }
.section-head h2 { font-size: clamp(26px, 3.6vw, 36px); font-weight: 800; letter-spacing: -0.01em; }
.section-head p { margin-top: 12px; color: var(--text-soft); font-size: 16px; }

/* ---------- Download ---------- */
.download-card {
  max-width: 860px; margin: 0 auto; background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius); box-shadow: var(--shadow); overflow: hidden;
}
.os-tabs { display: flex; gap: 6px; padding: 18px 18px 0; }
.os-tab {
  flex: 1; text-align: center; padding: 12px; border-radius: var(--radius-sm); cursor: pointer;
  font-weight: 600; color: var(--text-soft); border: 1px solid transparent; transition: all .18s;
}
.os-tab .ico { font-size: 22px; display: block; margin-bottom: 4px; }
.os-tab.active { background: var(--bg-soft); color: var(--text); border-color: var(--border); }
.os-tab:not(.active):hover { color: var(--text); }

.download-body { padding: 26px 28px 30px; }
.os-panel { display: none; }
.os-panel.active { display: block; animation: fade .25s ease; }
@keyframes fade { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }

.arch-row { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
@media (max-width: 620px) { .arch-row { grid-template-columns: 1fr; } }
.arch {
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
  padding: 18px 20px; border: 1px solid var(--border); border-radius: var(--radius-sm);
  background: #fff; transition: border-color .2s, box-shadow .2s, transform .15s;
}
.arch:hover { border-color: var(--primary); box-shadow: var(--shadow-sm); transform: translateY(-2px); }
.arch-info .name { font-weight: 700; font-size: 15px; }
.arch-info .meta { font-size: 12.5px; color: var(--text-faint); margin-top: 2px; }
.arch .dl-btn {
  display: inline-flex; align-items: center; gap: 7px; padding: 10px 18px; border-radius: 999px;
  background: var(--primary-grad); color: #fff; font-weight: 600; font-size: 14px; white-space: nowrap;
  box-shadow: 0 6px 16px rgba(109, 94, 252, 0.32);
}
.arch .dl-btn:hover { filter: brightness(1.05); }

.download-foot {
  display: flex; align-items: center; justify-content: space-between; gap: 18px; flex-wrap: wrap;
  margin-top: 22px; padding-top: 20px; border-top: 1px dashed var(--border);
}
.qr { display: flex; align-items: center; gap: 14px; }
.qr-box {
  width: 78px; height: 78px; border-radius: 12px; border: 1px solid var(--border);
  background:
    repeating-conic-gradient(#16182b 0% 25%, #fff 0% 50%) 0 0 / 16px 16px;
  position: relative; flex: none;
}
.qr-box::after { content: "QR"; position: absolute; inset: 0; display: grid; place-items: center; color: #fff; font-size: 12px; font-weight: 700; background: rgba(22,24,43,.55); border-radius: 11px; }
.qr-text .t { font-weight: 600; font-size: 14px; }
.qr-text .s { font-size: 12.5px; color: var(--text-faint); }
.help-link { font-size: 14px; color: var(--primary); font-weight: 600; }
.help-link:hover { text-decoration: underline; }

/* ---------- Features ---------- */
.features { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; }
@media (max-width: 920px) { .features { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 520px) { .features { grid-template-columns: 1fr; } }
.feature {
  background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 26px 22px; box-shadow: var(--shadow-sm); transition: transform .18s, box-shadow .2s;
}
.feature:hover { transform: translateY(-4px); box-shadow: var(--shadow); }
.feature .ficon {
  width: 46px; height: 46px; border-radius: 13px; display: grid; place-items: center;
  background: linear-gradient(135deg, rgba(109,94,252,.14), rgba(0,194,255,.14)); font-size: 22px; margin-bottom: 16px;
}
.feature h3 { font-size: 17px; font-weight: 700; }
.feature p { margin-top: 8px; color: var(--text-soft); font-size: 14px; }

/* ---------- Footer ---------- */
.footer { background: #11131f; color: #c7c9d6; padding: 52px 0 30px; }
.footer .container { display: grid; grid-template-columns: 1.6fr 1fr 1fr 1fr; gap: 30px; }
@media (max-width: 760px) { .footer .container { grid-template-columns: 1fr 1fr; } }
.footer .brand { color: #fff; margin-bottom: 14px; }
.footer p.desc { font-size: 14px; color: #8b8fa6; max-width: 280px; }
.footer h4 { color: #fff; font-size: 14px; margin-bottom: 14px; }
.footer ul { list-style: none; }
.footer li { margin-bottom: 10px; }
.footer a { color: #a7abc2; font-size: 14px; transition: color .2s; }
.footer a:hover { color: #fff; }
.footer-bottom {
  max-width: var(--maxw); margin: 36px auto 0; padding: 20px 24px 0; border-top: 1px solid #23263a;
  display: flex; justify-content: space-between; flex-wrap: wrap; gap: 10px; font-size: 13px; color: #7b7f96;
}

/* ---------- Docs page ---------- */
.docs-layout { display: grid; grid-template-columns: 250px 1fr; gap: 40px; padding: 40px 0 80px; }
@media (max-width: 820px) { .docs-layout { grid-template-columns: 1fr; } }
.docs-side { position: sticky; top: calc(var(--nav-h) + 20px); align-self: start; }
.docs-side h4 { font-size: 13px; color: var(--text-faint); text-transform: uppercase; letter-spacing: .08em; margin: 18px 0 10px; }
.docs-side a { display: block; padding: 8px 12px; border-radius: 8px; color: var(--text-soft); font-size: 14.5px; }
.docs-side a:hover, .docs-side a.active { background: var(--bg-soft); color: var(--primary); font-weight: 600; }
.docs-content h1 { font-size: 30px; font-weight: 800; margin-bottom: 8px; }
.docs-content .lead { color: var(--text-soft); margin-bottom: 28px; }
.docs-content h2 { font-size: 21px; font-weight: 700; margin: 34px 0 12px; }
.docs-content p { color: var(--text-soft); margin-bottom: 14px; }
.docs-content .placeholder {
  border: 1px dashed var(--border-strong); border-radius: var(--radius-sm); padding: 22px;
  color: var(--text-faint); background: var(--bg-soft); font-size: 14px; margin: 14px 0;
}
.docs-content code { background: var(--bg-soft); padding: 2px 7px; border-radius: 6px; font-size: 13px; color: #4a3fd6; }