body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
                   Roboto, "Helvetica Neue", Arial, "Noto Sans JP", sans-serif;
      line-height: 1.7;
      margin: 0;
      padding: 0;
      background: #0f1115;
      color: #eaeaea;
    }

    main {
      max-width: 860px;
      margin: 0 auto;
      padding: 24px 16px 64px;
    }

    h1 {
      font-size: 1.8rem;
      margin-bottom: 0.6em;
    }

    h2 {
      margin-top: 2.2em;
      font-size: 1.3rem;
      border-bottom: 1px solid #333;
      padding-bottom: 4px;
    }

    p {
      margin: 0.6em 0 1.2em;
      color: #ccc;
    }

    img {
      width: 100%;
      max-width: 320px;
      height: auto;
      object-fit: contain;
      border-radius: 8px;
      margin: 16px auto 28px;
      display: block;
    }


    .note {
      background: #1a1d24;
      border-left: 4px solid #6ab0ff;
      padding: 12px 16px;
      margin: 1.5em 0;
      color: #ddd;
      font-size: 0.95rem;
    }

    .note-sub {
      background: #1A1A55;
      border-left: 3px solid #333;
      color: #ccc;
    }

    .step {
      margin-top: 2em;
    }

    a {
      color: #6ab0ff;
      text-decoration: none;
    }

    a:hover {
      text-decoration: underline;
    }