:root {
  --blue: #007aff;
  --green: #34c759;
  --red: #ff3b30;
  --orange: #ff9500;
  --purple: #af52de;
  --ink: #1d1d1f;
  --ink-2: #42454a;
  --ink-3: #6b6f76;
  --line: rgba(0,0,0,0.08);
  --glass: rgba(255,255,255,0.62);
  --glass-strong: rgba(255,255,255,0.78);
  --shadow: 0 10px 30px rgba(20,30,60,0.12);
  --radius: 18px;
  --code-bg: #1c1c1e;
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Text", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --mono: "SF Mono", "JetBrains Mono", "Fira Code", Menlo, Consolas, "Courier New", monospace;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 84px; }
body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  line-height: 1.7;
  background: #eef2fb;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* 背景装饰光斑 */
.bg-orbs { position: fixed; inset: 0; z-index: -1; overflow: hidden; }
.orb { position: absolute; border-radius: 50%; filter: blur(70px); opacity: 0.55; }
.orb-a { width: 460px; height: 460px; background: #4a9bff; top: -120px; left: -80px; }
.orb-b { width: 420px; height: 420px; background: #b06bff; top: 30%; right: -120px; }
.orb-c { width: 380px; height: 380px; background: #34d6a0; bottom: -120px; left: 25%; }

.glass {
  background: var(--glass);
  backdrop-filter: blur(20px) saturate(160%);
  -webkit-backdrop-filter: blur(20px) saturate(160%);
  border: 1px solid rgba(255,255,255,0.6);
  box-shadow: var(--shadow);
}

/* 顶部导航 */
.topnav {
  position: sticky; top: 0; z-index: 50;
  display: flex; align-items: center; gap: 18px;
  padding: 10px 22px; margin: 10px 14px 0;
  border-radius: 16px;
}
.brand { display: flex; align-items: center; gap: 8px; font-weight: 700; color: var(--ink); text-decoration: none; white-space: nowrap; }
.brand-ic { width: 22px; height: 22px; fill: none; stroke: var(--blue); stroke-width: 1.8; stroke-linejoin: round; }
.navlinks { display: flex; gap: 4px; list-style: none; margin: 0; padding: 0; flex: 1; flex-wrap: wrap; }
.navlinks a {
  text-decoration: none; color: var(--ink-2); font-size: 14px;
  padding: 6px 11px; border-radius: 10px; transition: .18s;
}
.navlinks a:hover { background: rgba(0,122,255,0.10); color: var(--blue); }
.navlinks a.active { background: rgba(0,122,255,0.16); color: var(--blue); font-weight: 600; }
.nav-cta {
  text-decoration: none; color: #fff; background: var(--blue);
  padding: 8px 16px; border-radius: 11px; font-size: 14px; font-weight: 600;
  white-space: nowrap; transition: .18s;
}
.nav-cta:hover { filter: brightness(1.06); transform: translateY(-1px); }

/* HERO */
.hero { padding: 36px 14px 8px; }
.hero-inner { max-width: 920px; margin: 0 auto; padding: 40px 34px; border-radius: 26px; text-align: center; }
.eyebrow { display: inline-block; font-size: 13px; font-weight: 600; color: var(--blue); background: rgba(0,122,255,0.10); padding: 5px 14px; border-radius: 999px; margin-bottom: 16px; }
.hero h1 { font-size: clamp(28px, 5vw, 44px); line-height: 1.18; margin: 0 0 16px; letter-spacing: -0.02em; }
.lead { font-size: 16px; color: var(--ink-2); max-width: 720px; margin: 0 auto 22px; }
.lead strong { color: var(--ink); }
.chips { display: flex; gap: 8px; flex-wrap: wrap; justify-content: center; margin-bottom: 26px; }
.chip { font-size: 13px; padding: 6px 13px; border-radius: 999px; font-weight: 600; color: #fff; }
.chip-blue { background: var(--blue); } .chip-green { background: var(--green); }
.chip-orange { background: var(--orange); } .chip-red { background: var(--red); }
.hero-actions { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }
.btn { text-decoration: none; padding: 12px 26px; border-radius: 13px; font-weight: 600; font-size: 15px; transition: .18s; }
.btn-primary { background: var(--blue); color: #fff; box-shadow: 0 8px 20px rgba(0,122,255,0.30); }
.btn-primary:hover { filter: brightness(1.05); transform: translateY(-1px); }
.btn-ghost { background: rgba(255,255,255,0.7); color: var(--ink); border: 1px solid var(--line); }
.btn-ghost:hover { background: #fff; }

/* 主区域 */
.wrap { max-width: 920px; margin: 0 auto; padding: 26px 14px 40px; }
.sec { margin: 30px 0; scroll-margin-top: 84px; }
.sec-head { display: flex; align-items: center; gap: 14px; margin-bottom: 14px; }
.sec-ic { width: 44px; height: 44px; border-radius: 13px; display: grid; place-items: center; background: rgba(0,122,255,0.10); flex: none; }
.sec-ic svg { width: 24px; height: 24px; fill: none; stroke: var(--blue); stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.sec-no { font-size: 13px; font-weight: 700; color: var(--ink-3); letter-spacing: 0.05em; }
.sec-head h2 { font-size: 22px; margin: 2px 0 0; letter-spacing: -0.01em; }

.card { border-radius: var(--radius); padding: 24px 26px; }
.card p { margin: 0 0 14px; color: var(--ink-2); }
.card p.mt { margin-top: 18px; }
.card strong { color: var(--ink); }
.card code { font-family: var(--mono); font-size: 13.5px; background: rgba(0,0,0,0.06); padding: 2px 6px; border-radius: 6px; color: #b1341f; }
.card a { color: var(--blue); }

/* 键值表 */
.kv { display: grid; gap: 2px; border-radius: 14px; overflow: hidden; margin: 6px 0 4px; }
.kv > div { display: grid; grid-template-columns: 96px 1fr; gap: 14px; padding: 11px 14px; background: rgba(255,255,255,0.5); border-bottom: 1px solid var(--line); }
.kv > div:last-child { border-bottom: none; }
.kv .k { font-weight: 600; color: var(--ink); font-size: 14px; }
.kv .v { color: var(--ink-2); font-size: 14.5px; }
.kv .v code { color: #b1341f; }

/* 代码块 */
.codeblock { border-radius: 14px; overflow: hidden; margin: 14px 0; background: var(--code-bg); box-shadow: 0 8px 22px rgba(0,0,0,0.18); }
.cb-bar { display: flex; align-items: center; justify-content: space-between; padding: 8px 14px; background: rgba(255,255,255,0.06); border-bottom: 1px solid rgba(255,255,255,0.08); }
.cb-lang { font-family: var(--mono); font-size: 12px; color: #9aa0aa; letter-spacing: 0.02em; }
.cb-copy { font-family: var(--font); font-size: 12.5px; color: #cfd3da; background: rgba(255,255,255,0.10); border: 1px solid rgba(255,255,255,0.14); padding: 4px 12px; border-radius: 8px; cursor: pointer; transition: .15s; }
.cb-copy:hover { background: rgba(255,255,255,0.18); color: #fff; }
.cb-copy.done { color: var(--green); border-color: rgba(52,199,89,0.5); }
.codeblock pre { margin: 0; padding: 16px 18px; overflow-x: auto; }
.codeblock code { font-family: var(--mono); font-size: 13px; line-height: 1.65; color: #e6e8ec; background: none; padding: 0; white-space: pre; }
/* 长源码块可滚动 */
.codeblock.scroll pre { max-height: 460px; overflow: auto; }
.src-h { font-size: 17px; color: var(--ink); margin: 22px 0 10px; }
.dl-btn { display: inline-block; text-decoration: none; background: var(--blue); color: #fff; font-weight: 600; font-size: 14.5px; padding: 10px 20px; border-radius: 12px; box-shadow: 0 8px 20px rgba(0,122,255,0.28); transition: .18s; }
.dl-btn:hover { filter: brightness(1.06); transform: translateY(-1px); }
.card a { color: var(--blue); }

/* 提示框 */
.callout { display: flex; gap: 12px; align-items: flex-start; padding: 14px 16px; border-radius: 14px; margin: 16px 0 4px; }
.callout svg { width: 22px; height: 22px; flex: none; fill: none; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; margin-top: 2px; }
.callout p { margin: 0; font-size: 14.5px; color: var(--ink-2); }
.callout p strong { color: var(--ink); }
.callout-blue { background: rgba(0,122,255,0.08); } .callout-blue svg { stroke: var(--blue); }
.callout-green { background: rgba(52,199,89,0.10); } .callout-green svg { stroke: var(--green); }
.callout-orange { background: rgba(255,149,0,0.10); } .callout-orange svg { stroke: var(--orange); }
.callout-red { background: rgba(255,59,48,0.09); } .callout-red svg { stroke: var(--red); }

/* 步骤 */
.steps { display: grid; gap: 12px; margin: 6px 0; }
.step { display: flex; gap: 14px; align-items: flex-start; }
.step-no { width: 28px; height: 28px; flex: none; border-radius: 50%; background: var(--blue); color: #fff; font-weight: 700; font-size: 14px; display: grid; place-items: center; }
.step > div { flex: 1; }
.step strong { display: block; color: var(--ink); margin-bottom: 2px; }
.step p { margin: 0; font-size: 14.5px; color: var(--ink-2); }

/* FAQ */
.faq-item { padding: 14px 0; border-bottom: 1px solid var(--line); }
.faq-item:last-child { border-bottom: none; }
.faq-item h3 { margin: 0 0 6px; font-size: 16px; color: var(--ink); }
.faq-item p { margin: 0; font-size: 14.5px; color: var(--ink-2); }
.faq-item code { color: #b1341f; }

/* 结束卡 */
.endcard { border-radius: var(--radius); padding: 26px; display: flex; gap: 18px; align-items: center; margin-top: 34px; }
.endcard svg { width: 40px; height: 40px; flex: none; fill: none; stroke: var(--green); stroke-width: 2; stroke-linecap: round; stroke-linejoin: round; }
.endcard h3 { margin: 0 0 4px; font-size: 19px; }
.endcard p { margin: 0; color: var(--ink-2); font-size: 14.5px; }

/* 页脚 */
.foot { text-align: center; padding: 26px 14px 40px; color: var(--ink-3); font-size: 13px; }

/* 回到顶部 */
.totop { position: fixed; right: 20px; bottom: 22px; width: 46px; height: 46px; border-radius: 50%; border: none; background: var(--blue); color: #fff; display: grid; place-items: center; cursor: pointer; box-shadow: 0 8px 22px rgba(0,122,255,0.35); opacity: 0; transform: translateY(12px); pointer-events: none; transition: .22s; z-index: 60; }
.totop.show { opacity: 1; transform: translateY(0); pointer-events: auto; }
.totop svg { width: 22px; height: 22px; fill: none; stroke: #fff; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round; }

/* 响应式 */
@media (max-width: 720px) {
  .topnav { flex-wrap: wrap; gap: 10px; }
  .navlinks { order: 3; width: 100%; justify-content: flex-start; overflow-x: auto; }
  .nav-cta { margin-left: auto; }
  .hero-inner { padding: 30px 20px; }
  .card { padding: 20px 18px; }
  .kv > div { grid-template-columns: 80px 1fr; }
  .endcard { flex-direction: column; text-align: center; }
}