:root{
      --bg:#ffffff;
      --text:#111827;
      --muted:#6b7280;
      --line: rgba(107,42,58,0.12);
      --card:#f9fafb;
      --accent:#db6689;
      --warn-bg:#fff7ed;
      --warn-line:#fdba74;
      --shadow:0 6px 18px rgba(17,24,39,.06);
      --radius:4px;
      --max: 920px;
      --toc-h: 56px;
      --space: 16px;
    }

    /* Base */
    *{ box-sizing:border-box; }
    html{ scroll-behavior:smooth; }
    body{
      margin:0;
      font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Hiragino Sans", "Noto Sans JP", "Yu Gothic", sans-serif;
      color:var(--text);
      background:var(--bg);
      line-height:1.6;
    }
    a{ color:var(--accent); text-decoration:none; }
    a:hover{ text-decoration:underline; }
    img{ width: 280px; max-width:100%; height:auto; display:block; border-radius:12px; }
    code{ font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace; }
    .container{
      max-width:var(--max);
      margin:0 auto;
      padding: 0 var(--space);
    }

    /* Skip link */
    .skip{
      position:absolute; left:-999px; top:auto; width:1px; height:1px; overflow:hidden;
    }
    .skip:focus{
      left:16px; top:16px; width:auto; height:auto;
      padding:10px 12px; background:#fff; border:1px solid var(--line);
      border-radius:10px; box-shadow:var(--shadow); z-index:9999;
    }

    /* Header */
    header{
      padding: 18px 0 8px;
    }
    .title{
      font-size: 20px;
      margin: 0;
      letter-spacing: .02em;
      color: #6b2a3a;
    }
    .subtitle{
      margin: 6px 0 0;
      color: var(--muted);
      font-size: 13px;
    }

    /* Fixed TOC */
    .toc{
      position: sticky;
      top: 0;
      z-index: 1000;
      background: rgba(255,255,255,.92);
      backdrop-filter: blur(8px);
      border-bottom: 1px solid var(--line);
    }
    .toc-inner{
      display:flex;
      gap:10px;
      align-items:center;
      height: var(--toc-h);
      overflow-x:auto;
      -webkit-overflow-scrolling: touch;
      scrollbar-width: none;
    }
    .toc-inner::-webkit-scrollbar{ display:none; }
    .toc a{
      display:inline-flex;
      align-items:center;
      gap:8px;
      white-space:nowrap;
      padding: 10px 12px;
      border:1px solid var(--line);
      background:#fff;
      border-radius: 999px;
      font-size: 13px;
      color: var(--text);
    }
    .toc a:hover{ text-decoration:none; border-color:#cbd5e1; }
    .dot{
      width:8px; height:8px; border-radius:999px;
      background: var(--accent);
      flex:none;
    }

    /* Main layout */
    main{
      padding: 18px 0 48px;
    }
    section{
      scroll-margin-top: calc(var(--toc-h) + 14px);
      margin-top: 18px;
      padding-top: 1px;
    }
    #step1, #step2, #step3, #step4, #faq {
      margin-top: 80px;
    }
    .card{
      background: var(--card);
      border:1px solid var(--line);
      border-radius: var(--radius);
      padding: 16px;
      box-shadow: var(--shadow);
    }
    .section-head{
      display:flex;
      align-items:center;
      justify-content:space-between;
      gap:12px;
      margin-bottom: 10px;
    }
    h2{
      margin:0;
      font-size: 18px;
      line-height:1.3;
    }
    .badge{
      display:inline-flex;
      align-items:center;
      gap:6px;
      padding: 6px 10px;
      border-radius: 999px;
      border:1px solid var(--line);
      background:#fff;
      color: var(--muted);
      font-size: 12px;
      flex:none;
    }
    .step{
      display:inline-flex;
      align-items:center;
      justify-content:center;
      width:24px; height:24px;
      border-radius:999px;
      background: var(--accent);
      color:#fff;
      font-weight:700;
      font-size: 13px;
      flex:none;
    }

    /* Lists */
    .lead{
      margin: 0 0 12px;
      color: var(--muted);
      font-size: 14px;
    }
    ul{
      margin: 10px 0 0;
      padding-left: 0px;
      list-style-type: none;
    }
    li{ margin: 6px 0; }

    /* Warning box */
    .warn{
      margin-top: 12px;
      background: var(--warn-bg);
      border:1px solid var(--warn-line);
      border-radius: var(--radius);
      padding: 12px 14px;
    }
    .warn-title{
      display:flex; align-items:center; gap:8px;
      margin:0 0 6px;
      font-weight:700;
      font-size: 13px;
    }
    .warn p{
      margin:0;
      color:#7c2d12;
      font-size: 13px;
    }

    /* Figures (optional screenshots) */
    figure{
      margin: 12px 0 0;
      padding: 0;
    }
    figcaption{
      margin-top: 8px;
      color: var(--muted);
      font-size: 12px;
    }

    /* Details (FAQ) */
    details{
      background:#fff;
      border:1px solid var(--line);
      border-radius: 12px;
      padding: 12px 14px;
      margin-top: 10px;
    }
    summary{
      cursor:pointer;
      font-weight:700;
      font-size: 14px;
      list-style:none;
    }
    summary::-webkit-details-marker{ display:none; }
    details p{
      margin: 10px 0 0;
      color: var(--muted);
      font-size: 13px;
    }

    /* Footer */
    footer{
      border-top: 1px solid var(--line);
      padding: 18px 0 28px;
      color: var(--muted);
      font-size: 12px;
    }

    /* Slightly larger screens */
    @media (min-width: 768px){
      :root{ --space: 20px; }
      .title{ font-size: 22px; }
      h2{ font-size: 19px; }
      .card{ padding: 18px; }
    }

    .brand-logo {
        height: 40px;
        width: auto;
    }

    .site-footer{
        padding: 26px 0;
        border-top: 1px solid rgba(107,42,58,0.10);
        background: rgba(255,255,255,0.6);
    }

    .footer-inner{
        display: flex;
        justify-content: center;
        color: #6c6c6c;
    }