:root {
      --blue: #3B82F6;
      --green: #10B981;
      --violet: #8B5CF6;
      --amber: #F59E0B;
      --red: #EF4444;
      --navy: #0F172A;
      --slate: #1E293B;
      --slate-hi: #334155;
      --gray: #E5E7EB;
      --white: #FFFFFF;
      --page: #E5E7EB;
      --page-soft: #F3F4F6;
      --surface: #FFFFFF;
      --surface-raised: rgba(255, 255, 255, .86);
      --surface-tint: #F3F4F6;
      --fg: #111827;
      --muted: #6B7280;
      --muted-strong: #374151;
      --line: rgba(17, 24, 39, .12);
      --line-strong: rgba(17, 24, 39, .22);
      --font-display: Newsreader, "Iowan Old Style", Georgia, ui-serif, serif;
      --font-body: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
      --ease-standard: cubic-bezier(.2, .8, .2, 1);
      --motion-med: 420ms;
      color-scheme: light;
    }

    html[data-theme="dark"] {
      --page: #0F172A;
      --page-soft: #111C31;
      --surface: #1E293B;
      --surface-raised: rgba(30, 41, 59, .78);
      --surface-tint: #334155;
      --fg: #FFFFFF;
      --muted: #CBD5E1;
      --muted-strong: #E2E8F0;
      --line: rgba(255, 255, 255, .12);
      --line-strong: rgba(255, 255, 255, .22);
      color-scheme: dark;
    }

    * {
      box-sizing: border-box;
    }

    body {
      margin: 0;
      background: var(--page);
      color: var(--fg);
      font-family: var(--font-body);
      line-height: 1.65;
      transition: background-color var(--motion-med) var(--ease-standard), color var(--motion-med) var(--ease-standard);
    }

    .container {
      max-width: 800px;
      margin: 0 auto;
      padding: 40px 20px 80px;
    }

    header {
      margin-bottom: 40px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      border-bottom: 1px solid var(--line);
      padding-bottom: 24px;
    }

    .brand {
      display: inline-flex;
      align-items: center;
      gap: 10px;
      color: var(--fg);
      font-weight: 800;
      font-size: 20px;
      text-decoration: none;
    }

    .brand img {
      width: 40px;
      height: 40px;
      object-fit: contain;
    }

    .theme-toggle-btn {
      background: var(--surface);
      border: 1px solid var(--line);
      border-radius: 999px;
      padding: 6px 12px;
      color: var(--fg);
      font-size: 13px;
      font-weight: 700;
      cursor: pointer;
      box-shadow: 0 2px 4px rgba(0,0,0,0.05);
      transition: background-color var(--motion-med) var(--ease-standard), border-color var(--motion-med) var(--ease-standard);
    }

    .theme-toggle-btn:hover {
      background: var(--surface-tint);
    }

    .back-btn {
      display: inline-flex;
      align-items: center;
      gap: 6px;
      color: var(--muted);
      font-size: 14px;
      font-weight: 700;
      margin-bottom: 24px;
      text-decoration: none;
    }

    .back-btn:hover {
      color: var(--fg);
    }

    h1 {
      font-family: var(--font-display);
      font-size: clamp(34px, 6vw, 48px);
      line-height: 1.1;
      margin: 0 0 16px;
      font-weight: 700;
    }

    .post-meta {
      font-size: 14px;
      color: var(--muted);
      margin-bottom: 30px;
      display: flex;
      gap: 16px;
      border-bottom: 1px solid var(--line);
      padding-bottom: 16px;
    }

    .post-hero-image {
      width: 100%;
      height: 380px;
      object-fit: cover;
      border-radius: 18px;
      margin-bottom: 40px;
      border: 1px solid var(--line);
    }

    .article-content {
      background: var(--surface);
      border-radius: 18px;
      padding: 34px;
      box-shadow: 0 14px 34px rgba(15, 23, 42, 0.05);
      border: 1px solid var(--line);
      transition: background-color var(--motion-med) var(--ease-standard);
    }

    h2 {
      font-size: 24px;
      margin-top: 36px;
      margin-bottom: 14px;
      border-bottom: 1px solid var(--line);
      padding-bottom: 8px;
      color: var(--fg);
    }

    h3 {
      font-size: 19px;
      margin-top: 24px;
      margin-bottom: 8px;
      color: var(--fg);
    }

    p, li {
      color: var(--muted);
      font-size: 16px;
      line-height: 1.7;
    }

    ul, ol {
      padding-left: 20px;
      margin-bottom: 24px;
    }

    li {
      margin-bottom: 10px;
    }

    blockquote {
      margin: 30px 0;
      padding-left: 20px;
      border-left: 4px solid var(--blue);
      font-style: italic;
      color: var(--fg);
    }


    .research-note {
      margin: 24px 0 30px;
      padding: 18px 20px;
      border-left: 4px solid var(--green);
      border-radius: 12px;
      background: var(--surface-tint);
      color: var(--muted-strong);
    }

    .research-note strong {
      color: var(--fg);
    }

    .research-references {
      margin-top: 42px;
      padding-top: 12px;
      border-top: 1px solid var(--line);
    }

    .reference-list a {
      color: var(--fg);
      text-decoration: underline;
      text-decoration-thickness: 1px;
      text-underline-offset: 3px;
    }

    .reference-list a:hover,
    .reference-list a:focus-visible {
      color: var(--blue);
    }

    footer {
      text-align: center;
      margin-top: 60px;
      font-size: 13px;
      color: var(--muted);
      border-top: 1px solid var(--line);
      padding-top: 24px;
    }