:root{
  --bg:#f6f8fc;
  --panel:#ffffff;
  --ink:#14213d;
  --muted:#5b6b84;
  --line:#e3e9f2;
  --accent:#2563eb;
  --accent-soft:#e8effc;
  --dark:#0c1a30;
  --dark-2:#122544;
  --code-bg:#0d1b31;
  --warn-bg:#fff7e8;
  --warn-line:#f0d9a8;
  --radius:16px;
  --sidebar:290px;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{font-family:'Inter','Segoe UI',system-ui,sans-serif;background:var(--bg);color:var(--ink);line-height:1.65;-webkit-font-smoothing:antialiased}
a{color:var(--accent)}
:focus-visible{outline:3px solid var(--accent);outline-offset:2px;border-radius:6px}
code{font-family:'Cascadia Code',Consolas,'SF Mono',monospace;font-size:.9em;background:#eef2f8;padding:1px 6px;border-radius:6px}

.layout{display:grid;grid-template-columns:var(--sidebar) 1fr;max-width:1240px;margin:0 auto;min-height:100vh}

/* Sidebar */
.sidebar{position:sticky;top:0;height:100vh;overflow-y:auto;background:linear-gradient(180deg,var(--dark),var(--dark-2));color:#dbe6f5;padding:34px 28px}
.logo{font-size:1.45rem;font-weight:800;color:#fff;text-decoration:none;letter-spacing:-.02em;line-height:1.2;display:block}
.logo span{color:#7dd3fc}
.logo-sub{margin-top:14px;font-size:.92rem;color:#9db4d2;line-height:1.55}
.side-nav{margin-top:30px;display:flex;flex-direction:column;gap:4px}
.side-nav a{color:#c9daf2;text-decoration:none;font-size:.95rem;font-weight:500;padding:9px 12px;border-radius:10px}
.side-nav a:hover{background:rgba(255,255,255,.08);color:#fff}
.side-nav a.active{background:var(--accent);color:#fff}
.side-foot{margin-top:34px;font-size:.82rem;color:#7f96b5;line-height:1.6}
.lang-switch{margin-top:26px;font-size:.9rem;color:#7f96b5}
.lang-switch a{color:#c9daf2;text-decoration:none;font-weight:600}
.lang-switch a:hover{color:#fff}
.lang-switch a[aria-current="true"]{color:#7dd3fc}

/* Content */
.content{padding:48px 52px 60px;min-width:0}
.hero{margin-bottom:14px}
.hero h1{font-size:clamp(2rem,4.5vw,3.1rem);line-height:1.08;letter-spacing:-.03em;font-weight:800}
.hero-tag{margin-top:16px;font-size:1.12rem;color:var(--muted);max-width:640px}
.hero-meta{display:flex;flex-wrap:wrap;gap:10px;margin-top:22px}
.hero-meta span{background:var(--accent-soft);color:#1c4390;font-size:.85rem;font-weight:600;padding:7px 14px;border-radius:999px}

section{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:34px 36px;margin-top:26px;scroll-margin-top:20px}
section h2{font-size:1.5rem;letter-spacing:-.02em;margin-bottom:14px}
section h3{font-size:1.08rem;margin:24px 0 10px}
section p{color:#33456b;max-width:720px}
.steps{margin:12px 0 6px 22px;color:#33456b;max-width:720px}
.steps li{margin-bottom:10px}
ul.steps{list-style:disc}
.note{background:var(--accent-soft);border-radius:12px;padding:16px 18px;margin-top:18px;color:#1c3664;max-width:720px}
.note.warn{background:var(--warn-bg);border:1px solid var(--warn-line);color:#5c4712}

/* Code blocks */
.code{position:relative;background:var(--code-bg);border-radius:12px;margin:14px 0;max-width:720px}
.code pre{overflow-x:auto;padding:16px 18px}
.code code{background:none;padding:0;color:#d7e6ff;font-size:.9rem;line-height:1.6;white-space:pre}
.code .copy{position:absolute;top:10px;right:10px;background:rgba(255,255,255,.12);color:#eaf2ff;border:1px solid rgba(255,255,255,.22);font-size:.78rem;font-weight:600;padding:5px 12px;border-radius:8px;cursor:pointer}
.code .copy:hover{background:rgba(255,255,255,.22)}

/* Rules list */
.donts{list-style:none;max-width:720px}
.donts li{padding:12px 0;border-bottom:1px solid var(--line);color:#33456b}
.donts li:last-child{border-bottom:none}

/* Resources */
.res{list-style:none;max-width:760px}
.res li{padding:11px 0;border-bottom:1px solid var(--line);color:#33456b}
.res li:last-child{border-bottom:none}
.res a{font-weight:600;text-decoration:none}
.res a:hover{text-decoration:underline}

/* Funnel — author CTA */
.funnel{background:#0d1526;color:#dbe2f0;border-color:#0d1526}
.funnel h2{color:#fff;margin-bottom:10px}
.funnel p{max-width:640px;color:#dbe2f0}
.funnel strong{color:#fff}
.funnel-actions{display:flex;gap:12px;flex-wrap:wrap;margin-top:18px}
.funnel-btn{display:inline-block;text-decoration:none;font-weight:600;font-size:.95rem;padding:11px 22px;border-radius:999px;border:1px solid #31405f;color:#e8ecf5}
.funnel-btn:hover{border-color:#72809c}
.funnel-btn.primary{background:#e85d1f;border-color:#e85d1f;color:#fff}
.funnel-btn.primary:hover{background:#c74e15}

.foot{margin-top:30px;padding:0 6px}
.foot p{color:var(--muted);font-size:.86rem;max-width:760px}

/* Mobile */
@media (max-width:900px){
  .layout{grid-template-columns:1fr}
  .sidebar{position:sticky;top:0;height:auto;z-index:10;padding:18px 20px 14px}
  .logo-sub,.side-foot{display:none}
  .side-nav{flex-direction:row;overflow-x:auto;margin-top:12px;padding-bottom:6px;gap:6px;-webkit-overflow-scrolling:touch}
  .side-nav a{white-space:nowrap;font-size:.88rem;padding:7px 11px;background:rgba(255,255,255,.06)}
  .content{padding:26px 16px 44px}
  section{padding:24px 20px}
  .hero-meta span{font-size:.8rem}
}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
}

h1,h2,h3{font-family:'Sora','Inter',sans-serif}

/* UX parity: scroll progress, back-to-top, updated line */
.scroll-progress{position:fixed;top:0;left:0;height:3px;width:0;background:#e85d1f;z-index:1000}
.updated{margin-top:16px;color:var(--muted);font-size:.86rem}
.to-top{position:fixed;right:22px;bottom:22px;width:48px;height:48px;border-radius:50%;border:none;background:#0d1526;color:#fff;font-size:1.25rem;line-height:1;cursor:pointer;box-shadow:0 6px 18px rgba(13,21,38,.3);opacity:0;visibility:hidden;transform:translateY(8px);transition:opacity .25s ease,transform .25s ease,visibility .25s;display:flex;align-items:center;justify-content:center;z-index:999}
.to-top.show{opacity:1;visibility:visible;transform:translateY(0)}
.to-top:hover{background:#1d2c49}
@media (prefers-reduced-motion:reduce){.to-top{transition:none;transform:none}}