:root {
      --color-bg: #f8f6f0;
      --color-dark: #1a1a1a;
      --color-gold: #c9a227;
      --color-gold-light: #e3c96d;
      --color-text: #2c2c2a;
      --color-text-muted: #5f5e5a;
      --color-card: #ffffff;
      --color-red: #8b2635;
      --color-green: #2d5a4a;
      --color-blue: #2c4a6b;
      --color-border: rgba(0,0,0,0.08);
      --radius: 12px;
      --shadow: 0 8px 30px rgba(0,0,0,0.08);
      --shadow-hover: 0 16px 45px rgba(0,0,0,0.12);
    }
    * { margin: 0; padding: 0; box-sizing: border-box; }
    html { scroll-behavior: smooth; }
    body {
      font-family: 'Noto Serif SC', 'Source Han Serif SC', 'SimSun', 'STSong', Georgia, serif;
      background: var(--color-bg);
      color: var(--color-text);
      line-height: 1.8;
      overflow-x: hidden;
    }

    nav.blog-nav {
      position: fixed; top: 0; left: 0; width: 100%; z-index: 100;
      padding: 1rem 5%;
      display: flex; justify-content: space-between; align-items: center;
      background: rgba(26, 26, 26, 0.95);
      backdrop-filter: blur(10px);
      box-shadow: 0 2px 20px rgba(0,0,0,0.15);
    }
    nav.blog-nav .logo {
      font-size: 1.1rem; font-weight: 700; color: var(--color-gold);
      letter-spacing: 0.05em; text-decoration: none;
    }
    nav.blog-nav .logo span { color: rgba(255,255,255,0.5); font-weight: 400; font-size: 0.85rem; }
    nav.blog-nav ul { display: flex; list-style: none; gap: 1.75rem; }
    nav.blog-nav a.link {
      color: rgba(255,255,255,0.8); text-decoration: none;
      font-size: 0.9rem; font-weight: 600; transition: color 0.2s;
    }
    nav.blog-nav a.link:hover { color: var(--color-gold-light); }
    nav.blog-nav .back-home {
      color: var(--color-gold); font-weight: 600; font-size: 0.9rem;
      text-decoration: none; padding: 0.4rem 0.9rem;
      border: 1px solid var(--color-gold); border-radius: 20px; transition: all 0.2s;
    }
    nav.blog-nav .back-home:hover { background: var(--color-gold); color: #1a1a1a; }
    .mobile-menu-btn { display: none; background: none; border: none; color: var(--color-gold); font-size: 1.5rem; cursor: pointer; }

    .breadcrumb {
      padding: 6rem 5% 0; max-width: 1200px; margin: 0 auto;
    }
    .breadcrumb a { color: var(--color-text-muted); text-decoration: none; font-size: 0.85rem; }
    .breadcrumb a:hover { color: var(--color-gold); }
    .breadcrumb span { color: var(--color-text-muted); font-size: 0.85rem; margin: 0 0.5rem; }
    .breadcrumb .current { color: var(--color-text); }

    .subject-meta { max-width: 1200px; margin: 1rem auto 0; padding: 0 5%; }
    .subject-meta .tag {
      display: inline-block; background: var(--color-gold); color: #1a1a1a;
      font-size: 0.75rem; font-weight: 700; padding: 0.25rem 0.75rem;
      border-radius: 4px; letter-spacing: 0.05em;
    }
    .subject-meta .read-time { color: var(--color-text-muted); font-size: 0.85rem; margin-left: 0.75rem; }

    .hero {
      min-height: 70vh;
      background: linear-gradient(135deg, #1a1a1a 0%, #2d2d2d 50%, #1a1a1a 100%);
      display: flex; align-items: center; justify-content: center;
      position: relative; overflow: hidden;
      padding: 4rem 5% 4rem; margin-top: 1.5rem; text-align: center;
    }
    .hero::before {
      content: ''; position: absolute; top: 0; left: 0; right: 0; bottom: 0;
      background-image:
        radial-gradient(circle at 20% 30%, rgba(201,162,39,0.08) 0%, transparent 50%),
        radial-gradient(circle at 80% 70%, rgba(201,162,39,0.06) 0%, transparent 50%);
      pointer-events: none;
    }
    .hero-content { position: relative; z-index: 2; max-width: 800px; }
    .hero .label {
      display: inline-block; color: var(--color-gold); font-size: 0.85rem;
      letter-spacing: 0.3em; text-transform: uppercase; margin-bottom: 1.5rem;
      padding-bottom: 0.5rem; border-bottom: 1px solid rgba(201,162,39,0.3);
    }
    .hero h1 {
      font-size: clamp(2.5rem, 6vw, 4.5rem); color: #ffffff;
      font-weight: 700; margin-bottom: 1.5rem; letter-spacing: 0.1em;
    }
    .hero .subtitle {
      font-size: 1.15rem; color: rgba(255,255,255,0.75);
      margin-bottom: 2rem; font-weight: 400; line-height: 1.8;
    }
    .hero .keywords {
      display: flex; justify-content: center; gap: 1rem; flex-wrap: wrap;
      margin-top: 2rem;
    }
    .hero .keywords span {
      color: var(--color-gold); border: 1px solid rgba(201,162,39,0.4);
      padding: 0.4rem 1rem; border-radius: 20px; font-size: 0.85rem;
    }

    main { max-width: 820px; margin: 0 auto; padding: 4rem 5%; }

    section.block { margin-bottom: 5rem; }
    section.block h2 {
      font-size: 1.9rem; color: var(--color-dark); margin-bottom: 1.5rem;
      padding-bottom: 0.75rem; position: relative; font-weight: 700;
    }
    section.block h2::after {
      content: ''; position: absolute; bottom: 0; left: 0;
      width: 60px; height: 3px; background: var(--color-gold);
    }
    section.block h3 {
      font-size: 1.25rem; color: var(--color-dark); margin: 2rem 0 1rem; font-weight: 600;
    }
    section.block p {
      color: var(--color-text-muted); margin-bottom: 1.25rem; font-size: 1.02rem;
    }
    section.block p strong { color: var(--color-dark); }
    section.block .lead {
      font-size: 1.15rem; color: var(--color-text); line-height: 1.9;
      border-left: 3px solid var(--color-gold); padding-left: 1.5rem;
      margin: 2rem 0;
    }

    .diagram-wrap {
      background: var(--color-card); border-radius: var(--radius);
      padding: 2rem 1rem; box-shadow: var(--shadow); margin: 2rem 0;
    }
    .diagram-wrap svg { width: 100%; height: auto; display: block; }
    .diagram-caption {
      text-align: center; color: var(--color-text-muted); font-size: 0.9rem;
      margin-top: 1rem; font-style: italic;
    }

    .elements-grid {
      display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
      gap: 1.5rem; margin: 2rem 0;
    }
    .element-card {
      background: var(--color-card); border-radius: var(--radius);
      padding: 1.75rem; box-shadow: var(--shadow);
      border-top: 4px solid var(--color-gold); transition: transform 0.3s, box-shadow 0.3s;
    }
    .element-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-hover); }
    .element-card .num {
      font-size: 2rem; color: var(--color-gold); font-weight: 700;
      opacity: 0.4; line-height: 1; margin-bottom: 0.5rem;
    }
    .element-card h4 { font-size: 1.2rem; color: var(--color-dark); margin-bottom: 0.75rem; font-weight: 600; }
    .element-card p { color: var(--color-text-muted); font-size: 0.95rem; line-height: 1.7; margin: 0; }

    .types-list {
      display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
      gap: 1.25rem; margin: 2rem 0;
    }
    .type-item {
      background: var(--color-card); border-radius: var(--radius);
      padding: 1.5rem; box-shadow: var(--shadow);
      border-left: 4px solid var(--color-blue);
    }
    .type-item h5 { font-size: 1.05rem; color: var(--color-dark); margin-bottom: 0.5rem; font-weight: 600; }
    .type-item p { color: var(--color-text-muted); font-size: 0.9rem; margin: 0; line-height: 1.6; }

    .quote-block {
      background: var(--color-dark); color: #fff; border-radius: var(--radius);
      padding: 2.5rem; margin: 2rem 0; position: relative; overflow: hidden;
    }
    .quote-block::before {
      content: '"'; position: absolute; top: -1rem; left: 1rem;
      font-size: 8rem; color: rgba(201,162,39,0.2); font-family: Georgia, serif;
    }
    .quote-block p {
      position: relative; color: rgba(255,255,255,0.9);
      font-size: 1.1rem; line-height: 1.9; margin: 0; z-index: 1;
    }
    .quote-block .source {
      display: block; margin-top: 1rem; color: var(--color-gold);
      font-size: 0.9rem; font-weight: 600;
    }

    .ben-view {
      background: linear-gradient(135deg, #f8f6f0 0%, #f0ede4 100%);
      border-radius: var(--radius); padding: 2.5rem; margin: 2rem 0;
      border: 1px solid var(--color-gold); border-left: 5px solid var(--color-gold);
    }
    .ben-view .label {
      display: inline-block; background: var(--color-gold); color: #1a1a1a;
      font-size: 0.75rem; font-weight: 700; padding: 0.25rem 0.75rem;
      border-radius: 4px; margin-bottom: 1rem; letter-spacing: 0.05em;
    }
    .ben-view h3 { color: var(--color-dark); margin-bottom: 1rem; font-size: 1.3rem; }
    .ben-view p { color: var(--color-text-muted); margin-bottom: 1rem; }
    .ben-view p:last-child { margin-bottom: 0; }

    .related-articles {
      background: var(--color-card); border-radius: var(--radius);
      padding: 2rem; box-shadow: var(--shadow); margin: 2rem 0; text-align: center;
    }
    .related-articles h3 { color: var(--color-dark); margin-bottom: 1rem; }
    .related-articles .related-link {
      display: block; text-align: left; text-decoration: none;
      color: var(--color-dark); background: rgba(201,162,39,0.08);
      border-left: 3px solid var(--color-gold); border-radius: 6px;
      padding: 1rem 1.25rem; margin-bottom: 1rem; line-height: 1.7;
      transition: all 0.3s;
    }
    .related-articles .related-link:hover { background: rgba(201,162,39,0.16); transform: translateX(3px); }
    .related-articles .empty {
      color: var(--color-text-muted); font-style: italic;
      padding: 1.5rem; border: 1px dashed var(--color-border); border-radius: 8px;
    }

    .annotation-block {
      background: #f4f7f9; border-radius: var(--radius);
      padding: 2.5rem; margin: 2rem 0;
      border: 1px solid #9bb4c4; border-left: 5px solid #4a7a9b;
    }
    .annotation-block .label {
      display: inline-block; background: #4a7a9b; color: #fff;
      font-size: 0.75rem; font-weight: 700; padding: 0.25rem 0.75rem;
      border-radius: 4px; margin-bottom: 1rem; letter-spacing: 0.05em;
    }
    .annotation-block h3 { color: var(--color-dark); margin-bottom: 1rem; font-size: 1.3rem; }
    .annotation-block p { color: var(--color-text-muted); margin-bottom: 1rem; }
    .annotation-block p:last-of-type { margin-bottom: 0; }
    .annotation-block .source-link {
      display: inline-block; margin-top: 0.5rem; color: #2c5d7c;
      font-weight: 600; text-decoration: none; border-bottom: 1px solid #9bb4c4;
    }
    .annotation-block .source-link:hover { color: #1a3a4d; }
    .annotation-block .source-link::after { content: " ↗"; font-size: 0.85em; }

    .back-section { text-align: center; margin: 3rem 0; }
    .back-btn {
      display: inline-block; background: var(--color-dark); color: #fff;
      text-decoration: none; padding: 0.9rem 2rem; border-radius: 30px;
      font-weight: 600; transition: all 0.3s; border: 2px solid var(--color-dark);
    }
    .back-btn:hover { background: var(--color-gold); color: #1a1a1a; border-color: var(--color-gold); }

    footer {
      background: var(--color-dark); color: rgba(255,255,255,0.6);
      padding: 3rem 5%; text-align: center; margin-top: 4rem;
    }
    footer p { margin-bottom: 0.5rem; font-size: 0.9rem; }
    footer .heart { color: var(--color-red); }

    @media (max-width: 768px) {
      nav.blog-nav ul { display: none; }
      .mobile-menu-btn { display: block; }
      .hero { min-height: 60vh; padding: 3rem 5%; }
      main { padding: 3rem 5%; }
      .ben-view, .quote-block, .annotation-block { padding: 1.75rem; }
    }