/* ===== 2026/06/30新設 ===== */
    *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

    :root {
      --c-ink: #0f0f0f;
      --c-muted: #6b6b6b;
      --c-border: #e2e2e2;
      --c-surface: #f7f6f3;
      --c-white: #ffffff;
      --c-accent: #1a6bff;
      --c-accent-dim: #e8efff;
      --font: "Gen Interface JP", sans-serif;
      --mono: 'DM Mono', monospace;
      --p-blue: #1d9bf0;
      --p-blue-hover: #1a8cd8;
      --bg: #f7f9f9;
      --surface: #ffffff;
      --text-primary: #0f1419;
      --text-secondary: #536471;
      --border: #eff3f4;
      --link: #1d9bf0;
      --link-hover: #1a8cd8;
      --nav-height: 53px;
      --accent: #0059FF;
    }

    html { scroll-behavior: smooth; }

    body {
      font-family: var(--font);
      background: var(--c-white);
      color: var(--c-ink);
      -webkit-font-smoothing: antialiased;
    }

    /* ── HEADER ── */
    header {
      position: sticky;
      top: 0;
      z-index: 100;
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 0 48px;
      height: 64px;
      background: rgba(255,255,255,0.88);
      backdrop-filter: blur(16px);
      -webkit-backdrop-filter: blur(16px);
      border-bottom: 1px solid var(--c-border);
    }

    .header-left {
      display: flex;
      align-items: center;
      gap: 14px;
    }

    .header-left img {
      height: 20px;
      width: auto;
    }

    .header-divider {
      width: 1px;
      height: 18px;
      background: var(--c-border);
    }

    .header-label {
      font-size: 13px;
      font-weight: 500;
      letter-spacing: 0.04em;
      color: var(--c-muted);
      text-transform: uppercase;
    }

    .btn-login {
      display: inline-flex;
      align-items: center;
      gap: 6px;
      padding: 8px 20px;
      font-family: var(--font);
      font-size: 13px;
      font-weight: 500;
      color: var(--c-ink);
      background: transparent;
      border: 1px solid var(--c-border);
      border-radius: 38px;
      cursor: pointer;
      transition: background 0.15s, border-color 0.15s;
      text-decoration: none;
    }

    .btn-login:hover {
      background: var(--c-surface);
      border-color: #c2c2c2;
    }

    /* ===== MAIN ===== */
    main {
      max-width: 760px;
      margin: 0 auto;
      padding: 48px 24px 80px;
    }

    /* ===== TOP NOTICE ===== */
    .notice-bar {
      display: flex;
      align-items: flex-start;
      gap: 10px;
      background: #e8f5fd;
      border: 1px solid #b3d9f5;
      border-radius: 12px;
      padding: 14px 18px;
      margin-bottom: 40px;
      font-size: 14px;
      color: var(--text-secondary);
      animation: fadeSlideIn 0.5s ease both;
    }

    .notice-bar .icon {
      flex-shrink: 0;
      width: 18px;
      height: 18px;
      color: var(--p-blue);
      margin-top: 1px;
    }

    .notice-bar a {
      color: var(--link);
      text-decoration: none;
      font-weight: 600;
    }

    .notice-bar a:hover {
      text-decoration: underline;
    }

    /* ===== PAGE TITLE ===== */
    .page-title {
      font-size: 60px;
      font-weight: 800;
      color: var(--text-primary);
      letter-spacing: -0.02em;
      margin-bottom: 36px;
      animation: fadeSlideIn 0.45s ease both;
    }

    .article-meta {
      display: flex; align-items: center; gap: 12px;
      font-size: 13px; color: var(--text-secondary);
    }
    .article-meta .dot { color: #ccc; }

     /* ===== ARTICLE BODY ===== */
    .article-body {
      background: var(--surface); border: 1px solid var(--border);
      border-radius: 16px; padding: 28px 30px;
    }

    /* ========================================
         本文の書き方:
         <p> タグで段落
         <h2> / <h3> で見出し
         <ul><li> でリスト
         <a href="..."> でリンク
         <div class="info-box"> で注意書きボックス
         <div class="step"> でステップ
    ======================================== -->

    .article-body p { margin-bottom: 16px; color: var(--text-primary); line-height: 1.75; }
    .article-body p:last-child { margin-bottom: 0; }
    .article-body h2 { font-size: 18px; font-weight: 700; margin: 28px 0 12px; color: var(--text-primary); }
    .article-body h3 { font-size: 15px; font-weight: 700; margin: 20px 0 8px; color: var(--text-primary); }
    .article-body ul, .article-body ol { padding-left: 22px; margin-bottom: 16px; }
    .article-body li { margin-bottom: 8px; line-height: 1.65; }
    .article-body a { color: var(--p-blue); text-decoration: none; }
    .article-body a:hover { text-decoration: underline; }

    /* 注意書きボックス */
    .info-box {
      background: #e8f5fd; border-left: 3px solid var(--p-blue);
      border-radius: 0 10px 10px 0; padding: 14px 18px; margin: 20px 0;
      font-size: 14px; color: var(--text-secondary);
    }
    .info-box i { color: var(--p-blue); margin-right: 6px; }

    /* ステップ */
    .step {
      display: flex; gap: 14px; margin-bottom: 16px; align-items: flex-start;
    }
    .step-num {
      flex-shrink: 0; width: 28px; height: 28px; border-radius: 50%;
      background: var(--p-blue); color: #fff;
      display: flex; align-items: center; justify-content: center;
      font-size: 13px; font-weight: 700; margin-top: 2px;
    }
    .step-body { flex: 1; }
    .step-body strong { display: block; font-weight: 600; margin-bottom: 4px; }
    .step-body p { margin: 0; font-size: 14px; color: var(--text-secondary); }   

    .article-img {
    width: 90%;
    max-width: 360px;
    height: auto;
    }

    /* ── RESPONSIVE ── */
    @media (max-width: 768px) {
      .page-title { font-size: 30px; font-weight: 800; color: var(--text-primary); letter-spacing: -0.02em; margin-bottom: 36px; animation: fadeSlideIn 0.45s ease both;}
    }

    @media screen and (min-width: 768px) {
      .article-img { max-width: 800px; }
    }

    /* ===== VERSION LIST ===== */
    .version-list {
      display: flex;
      flex-direction: column;
      gap: 0;
      border: 1px solid var(--border);
      border-radius: 16px;
      background: var(--surface);
      overflow: hidden;
      box-shadow: 0 1px 3px rgba(0,0,0,0.04);
      animation: fadeSlideIn 0.5s ease 0.1s both;
    }

    .version-item {
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 16px 24px;
      text-decoration: none;
      color: var(--link);
      font-size: 15px;
      font-weight: 500;
      border-bottom: 1px solid var(--border);
      transition: background 0.12s ease;
      gap: 12px;
    }

    .version-item:last-child {
      border-bottom: none;
    }

    .version-item:hover {
      background: #f7f9f9;
    }

    .version-item:hover .version-arrow {
      transform: translateX(3px);
      opacity: 1;
    }

    .version-label {
      display: flex;
      align-items: center;
      gap: 12px;
    }

    .version-badge {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      background: #e8f5fd;
      color: var(--twitter-blue);
      font-size: 11px;
      font-weight: 700;
      letter-spacing: 0.04em;
      border-radius: 6px;
      padding: 2px 8px;
      min-width: 28px;
      text-transform: uppercase;
    }

    .version-date {
      color: var(--text-secondary);
      font-size: 13.5px;
      font-weight: 400;
    }

    .version-arrow {
      color: var(--twitter-blue);
      opacity: 0.4;
      transition: transform 0.15s ease, opacity 0.15s ease;
      flex-shrink: 0;
    }

    /* ===== FOOTER ===== */
    footer {
      text-align: center;
      padding: 32px 24px;
      color: var(--text-secondary);
      font-size: 13px;
    }

    footer a {
      color: var(--text-secondary);
      text-decoration: none;
    }

    footer a:hover {
      text-decoration: underline;
      color: var(--twitter-blue);
    }

    /* ── RESPONSIVE ── */
    @media (max-width: 768px) {
      header { padding: 0 24px; }
      .hero-content { padding: 64px 24px; }
      .section-data { padding: 64px 24px; }
      .data-grid { grid-template-columns: 1fr; }
      .data-card.featured {
        grid-template-columns: 1fr;
        gap: 24px;
      }
      .article-img {  max-width: 800px;  }
      .info-strip { padding: 40px 24px; }
      .info-strip-inner { grid-template-columns: 1fr; gap: 28px; }
      footer { padding: 28px 24px; }
    }

    /* ===== UPDATE ===== */
    .update-bar {
      display: flex;
      align-items: flex-start;
      gap: 10px;
      background: #e8f5fd;
      border: 1px solid #b3d9f5;
      border-radius: 12px;
      padding: 14px 18px;
      margin-bottom: 40px;
      font-size: 14px;
      color: var(--text-secondary);
      animation: fadeSlideIn 0.5s ease both;
    }

    .update-bar .icon {
      flex-shrink: 0;
      width: 18px;
      height: 18px;
      color: var(--twitter-blue);
      margin-top: 1px;
    }

    .update-bar a {
      color: var(--link);
      text-decoration: none;
      font-weight: 600;
    }

    .update-bar a:hover {
      text-decoration: underline;
    }
        h2 { font-size: 20px; margin-top: 30px; margin-bottom: 15px; display: flex; align-items: center; gap: 10px; }
        h2 i { color: var(--accent); }
    
        .policy-box { background: #fffbeb; border: 1px solid #fef3c7; padding: 20px; border-radius: 12px; margin-bottom: 20px; }
        .policy-box h3 { font-size: 16px; margin-bottom: 10px; color: #92400e; }
        
        .do-list, .dont-list { list-style: none; padding: 0; }
        .do-list li::before { content: "✨"; margin-right: 10px; }
        .dont-list li::before { content: "❌"; margin-right: 10px; }
        li { margin-bottom: 10px; font-size: 15px; }

        .footer-note { text-align: center; margin-top: 40px; padding-top: 20px; border-top: 1px solid var(--border); color: var(--text-sub); font-size: 14px; }