:root{
      --bg:#0b0f19; --panel:#111726; --panel-2:#0e1422;
      --text:#e8ecf1; --muted:#a7b0c0;
      --brand:#4da3ff; --accent:#7cf1c9;
      --border:rgba(255,255,255,.08);
      --shadow:0 10px 30px rgba(0,0,0,.35);
      --radius:16px; --radius-lg:22px;
      --content-max:980px;
    }
    *{box-sizing:border-box}
    body{margin:0;font-family:system-ui,-apple-system,Segoe UI,Roboto,"Noto Sans JP","Hiragino Kaku Gothic ProN","Yu Gothic",Meiryo,sans-serif;line-height:1.75;color:var(--text);background:linear-gradient(180deg,#0b0f19 0%,#0a1322 100%)}
    img{max-width:100%;display:block}
    a{color:inherit;text-decoration:none}
    .container{max-width:var(--content-max);margin:0 auto;padding:0 20px}

    /* header */
    .site-header{position:sticky;top:0;z-index:50;background:linear-gradient(180deg,rgba(30,40,60,.96),rgba(30,40,60,.88));border-bottom:1px solid var(--border);backdrop-filter:saturate(1.1) blur(8px)}
    .header-inner{display:flex;align-items:center;gap:12px;padding:12px 0}
    .brand{display:flex;align-items:center;gap:10px}
    .brand-logo{width:36px;height:36px;object-fit:contain;background:none}
    .brand-title{font-weight:800;color:#fff}
    .nav{margin-left:auto;display:flex;gap:8px;flex-wrap:wrap}
    .nav a{padding:8px 12px;border-radius:10px;color:#f0f4fa;font-weight:600}
    .nav a[aria-current="page"],.nav a:hover{background:rgba(255,255,255,.12);color:#fff}

    /* hero */
    .hero{padding:26px 0 8px}
    .hero-card{background:var(--panel);border:1px solid var(--border);border-radius:var(--radius-lg);padding:20px;box-shadow:var(--shadow)}
    .hero h1{margin:0 0 6px;font-size:clamp(1.3rem,2.2vw + 1rem,2.2rem)}
    .hero p{margin:0;color:var(--muted)}

    /* section shells */
    .card{background:var(--panel);border:1px solid var(--border);border-radius:var(--radius);padding:18px;margin:16px 0}
    .card h2{margin:0 0 10px;font-size:1.2rem}
    .lead{color:var(--muted)}

    /* TOC */
    .toc a{display:inline-block;margin:6px 8px 0 0;padding:8px 12px;border:1px solid var(--border);border-radius:999px;background:rgba(255,255,255,.03);color:var(--muted)}
    .toc a:hover{background:rgba(255,255,255,.08);color:#fff}
    .toc summary{display:none}

    /* code & gallery */
    pre{background:#0f1523;color:#e8ecf1;padding:12px;border-radius:12px;border:1px solid var(--border);overflow:auto;font-size:.95rem}
    code{font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,"Liberation Mono",monospace}
    .gallery{display:grid;gap:10px;grid-template-columns:repeat(12,1fr)}
    .gallery figure{grid-column:span 12;margin:0;border:1px solid var(--border);border-radius:12px;overflow:hidden}
    .gallery figcaption{padding:8px 10px;font-size:.9rem;color:var(--muted);background:rgba(255,255,255,.03);border-top:1px solid var(--border)}
    .w6{grid-column:span 6}

    /* footer */
    footer{margin:36px 0 72px;color:var(--muted);text-align:center}

    /* responsive */
    @media (max-width:768px){
      .container{padding:0 12px}
      .brand-logo{width:30px;height:30px}
      .nav{width:100%;justify-content:flex-end}
      .hero-card{padding:16px}
      .card{padding:14px}
      .toc summary{display:block;cursor:pointer;font-weight:700;margin:-4px 0 8px}
      .toc[open] summary{margin-bottom:6px}
      .toc a{padding:7px 10px}
      .w6{grid-column:span 12}
      pre{font-size:.9rem;padding:10px}
    }