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

    :root {
      --bg:       #f4f6f8;
      --surface:  #ffffff;
      --surface2: #eef1f4;
      --border:   rgba(0,0,0,0.08);
      --accent:   #1cc47e;
      --accent2:  #0ea371;
      --accent3:  #0284c7;
      --text:     #0f1923;
      --muted:    #5c6773;
      --radius:   14px;
    }

    html { scroll-behavior: smooth; }

    body {
      font-family: 'Inter', sans-serif;
      background: var(--bg);
      color: var(--text);
      min-height: 100vh;
      overflow-x: hidden;
    }

    /* ── Nav ── */
    nav {
      position: sticky; top: 0; z-index: 100;
      background: rgba(255,255,255,0.85); backdrop-filter: blur(20px);
      border-bottom: 1px solid var(--border);
      display: flex; align-items: center; justify-content: space-between;
      padding: 1rem 2.5rem;
    }
    .nav-logo {
      font-family: 'Syne', sans-serif; font-size: 1.5rem; font-weight: 800;
      letter-spacing: -0.05em;
      background: linear-gradient(135deg, var(--accent), var(--accent2));
      -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
      text-decoration: none;
    }
    .nav-back {
      font-size: 0.85rem; color: var(--muted); text-decoration: none;
      display: flex; align-items: center; gap: 0.4rem; transition: color 0.2s;
    }
    .nav-back:hover { color: var(--text); }
    @media (max-width: 600px) { nav { padding: 1rem 1.25rem; } }

    /* ── Layout ── */
    .page-wrap {
      max-width: 1100px; margin: 0 auto;
      padding: 3.5rem 2rem 6rem;
      display: grid;
      grid-template-columns: 220px 1fr;
      gap: 4rem;
      align-items: start;
    }
    @media (max-width: 860px) {
      .page-wrap { grid-template-columns: 1fr; gap: 2rem; }
      .toc-wrap { display: none; }
    }

    /* ── TOC Sidebar ── */
    .toc-wrap { position: sticky; top: 5.5rem; }
    .toc-label {
      font-size: 0.72rem; font-weight: 700; letter-spacing: 0.1em;
      text-transform: uppercase; color: var(--muted); margin-bottom: 1rem;
    }
    .toc-list { list-style: none; display: flex; flex-direction: column; gap: 0.1rem; }
    .toc-list a {
      display: block; font-size: 0.8rem; color: var(--muted);
      text-decoration: none; padding: 0.3rem 0.75rem;
      border-left: 2px solid transparent;
      transition: all 0.2s; line-height: 1.4;
    }
    .toc-list a:hover { color: var(--text); border-left-color: var(--border); }
    .toc-list a.active { color: var(--accent); border-left-color: var(--accent); }

    /* ── Article ── */
    .article-header { margin-bottom: 3rem; }
    .article-header .eyebrow {
      font-size: 0.75rem; font-weight: 700; letter-spacing: 0.12em;
      text-transform: uppercase; color: var(--accent); margin-bottom: 0.75rem;
    }
    .article-header h1 {
      font-family: 'Plus Jakarta Sans', sans-serif;
      font-size: clamp(2rem, 4vw, 2.8rem);
      font-weight: 800; letter-spacing: -0.03em; line-height: 1.1;
      margin-bottom: 1rem;
    }
    .article-header .meta { font-size: 0.82rem; color: var(--muted); }

    .article-body section {
      margin-bottom: 3rem;
      border-top: 1px solid var(--border);
      padding-top: 2rem;
    }
    .article-body section:first-child { border-top: none; padding-top: 0; }

    .article-body h2 {
      font-family: 'Plus Jakarta Sans', sans-serif;
      font-size: 1.25rem; font-weight: 700; letter-spacing: -0.02em;
      margin-bottom: 1rem; color: var(--text);
      display: flex; align-items: center; gap: 0.5rem;
    }
    .article-body h2 .sec-num {
      font-size: 0.72rem; font-weight: 700;
      background: rgba(74,240,164,0.1); border: 1px solid rgba(74,240,164,0.25);
      color: var(--accent); padding: 0.15rem 0.5rem; border-radius: 99px;
      letter-spacing: 0.04em; flex-shrink: 0;
    }
    .article-body h3 {
      font-family: 'Plus Jakarta Sans', sans-serif;
      font-size: 1rem; font-weight: 700;
      margin: 1.5rem 0 0.6rem; color: var(--text);
    }
    .article-body p {
      font-size: 0.92rem; line-height: 1.75; color: #3a4652;
      margin-bottom: 0.9rem;
    }
    .article-body ul, .article-body ol {
      margin: 0.6rem 0 0.9rem 0; padding-left: 0;
      list-style: none; display: flex; flex-direction: column; gap: 0.5rem;
    }
    .article-body ul li, .article-body ol li {
      font-size: 0.92rem; line-height: 1.65; color: #3a4652;
      padding-left: 1.4rem; position: relative;
    }
    .article-body ul li::before {
      content: '–'; position: absolute; left: 0; color: var(--accent);
    }
    .article-body ol { counter-reset: li; }
    .article-body ol li { counter-increment: li; }
    .article-body ol li::before {
      content: counter(li) '.'; position: absolute; left: 0;
      color: var(--accent); font-weight: 600; font-size: 0.85rem;
    }

    .callout {
      background: rgba(74,240,164,0.06); border: 1px solid rgba(74,240,164,0.2);
      border-radius: 10px; padding: 1rem 1.25rem; margin: 1rem 0;
      font-size: 0.88rem; line-height: 1.65; color: var(--accent2);
    }
    .callout strong { color: var(--accent); }

    .warning-callout {
      background: rgba(251,191,36,0.06); border: 1px solid rgba(251,191,36,0.2);
      border-radius: 10px; padding: 1rem 1.25rem; margin: 1rem 0;
      font-size: 0.88rem; line-height: 1.65; color: #92600a;
    }

    /* ── Footer ── */
    footer {
      background: var(--surface); border-top: 1px solid var(--border);
      padding: 3.5rem 2rem 2rem;
    }
    .footer-inner { max-width: 1160px; margin: 0 auto; }
    .footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 3rem; margin-bottom: 3rem; }
    .footer-brand .nav-logo { display: inline-block; margin-bottom: 1rem; }
    .footer-brand p { font-size: 0.85rem; color: var(--muted); line-height: 1.65; max-width: 260px; }
    .footer-col h4 { font-family: 'Plus Jakarta Sans', sans-serif; font-size: 0.82rem; font-weight: 700; letter-spacing: 0.08em; text-transform: uppercase; color: var(--muted); margin-bottom: 1.1rem; }
    .footer-col a { display: block; font-size: 0.85rem; color: var(--muted); text-decoration: none; margin-bottom: 0.65rem; transition: color 0.2s; }
    .footer-col a:hover { color: var(--text); }
    .footer-bottom { border-top: 1px solid var(--border); padding-top: 1.5rem; display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 1rem; }
    .footer-copy { font-size: 0.8rem; color: var(--muted); }
    .footer-links { display: flex; gap: 1.5rem; }
    .footer-links a { font-size: 0.8rem; color: var(--muted); text-decoration: none; transition: color 0.2s; }
    .footer-links a:hover { color: var(--text); }
    @media (max-width: 768px) { .footer-grid { grid-template-columns: 1fr 1fr; } }
    @media (max-width: 480px) { .footer-grid { grid-template-columns: 1fr; } }