.btn {
          display: inline-flex;
          align-items: center;
          justify-content: center;
          gap: var(--space-xs);
          font-family: var(--font-sans);
          font-weight: var(--font-weight-semibold);
          border-radius: var(--radius-md);
          border: none;
          cursor: pointer;
          transition: transform var(--transition-fast), box-shadow var(--transition-fast), background var(--transition-fast);
          text-decoration: none;
        }

        .btn:hover:not(:disabled) {
          transform: translateY(-2px);
        }

        .btn:active:not(:disabled) {
          transform: translateY(0);
        }

        .btn:disabled {
          opacity: 0.5;
          cursor: not-allowed;
        }

        /* Variants */
        .btn-primary {
          background: var(--gradient-primary);
          color: white;
        }

        .btn-primary:hover:not(:disabled) {
          box-shadow: var(--shadow-lg);
        }

        .btn-secondary {
          background: var(--color-bg-tertiary);
          color: var(--color-text-primary);
        }

        .btn-secondary:hover:not(:disabled) {
          background: var(--color-bg-secondary);
          box-shadow: var(--shadow-md);
        }

        .btn-outline {
          background: transparent;
          color: var(--color-accent-primary);
          border: var(--border-width-thick) solid var(--color-accent-primary);
        }

        .btn-outline:hover:not(:disabled) {
          background: var(--color-accent-primary);
          color: white;
        }

        .btn-ghost {
          background: transparent;
          color: var(--color-text-secondary);
        }

        .btn-ghost:hover:not(:disabled) {
          background: var(--color-bg-secondary);
          color: var(--color-text-primary);
        }

        /* Sizes */
        .btn-sm {
          padding: var(--space-xs) var(--space-md);
          font-size: var(--font-size-sm);
        }

        .btn-md {
          padding: var(--space-sm) var(--space-lg);
          font-size: var(--font-size-base);
        }

        .btn-lg {
          padding: var(--space-md) var(--space-xl);
          font-size: var(--font-size-lg);
        }
      


        .glass-nav {
          margin: 20px 20px 0;
          padding: 16px 32px;
          border-radius: 16px;
          position: sticky;
          top: 20px;
          z-index: 100;
        }

        .nav-container {
          display: flex;
          align-items: center;
          justify-content: space-between;
          gap: 32px;
        }

        .nav-logo {
          text-decoration: none;
        }

        .logo-text {
          font-size: 24px;
          font-weight: 800;
          background: linear-gradient(135deg, #fff 0%, #8b5cf6 100%);
          -webkit-background-clip: text;
          -webkit-text-fill-color: transparent;
          background-clip: text;
        }

        .nav-links {
          display: flex;
          align-items: center;
          gap: 32px;
          flex: 1;
          justify-content: center;
        }

        .nav-link {
          color: rgba(255, 255, 255, 0.8);
          text-decoration: none;
          font-size: 15px;
          font-weight: 500;
          transition: color 0.2s;
          text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
        }

        .nav-link:hover,
        .nav-link.active {
          color: #fff;
        }

        .nav-cta {
          flex-shrink: 0;
        }

        /* Hamburger — hidden on desktop */
        .nav-hamburger {
          display: none;
          flex-direction: column;
          gap: 5px;
          padding: 8px;
          cursor: pointer;
          background: none;
          border: none;
        }

        .hamburger-line {
          display: block;
          width: 24px;
          height: 2px;
          background: rgba(255, 255, 255, 0.9);
          border-radius: 2px;
          transition: transform 0.3s, opacity 0.3s;
        }

        .hamburger-line.open:nth-child(1) {
          transform: rotate(45deg) translate(5px, 5px);
        }

        .hamburger-line.open:nth-child(2) {
          opacity: 0;
        }

        .hamburger-line.open:nth-child(3) {
          transform: rotate(-45deg) translate(5px, -5px);
        }

        /* Mobile dropdown — hidden on desktop */
        .nav-mobile-dropdown {
          display: none;
        }

        /* ===== MOBILE ===== */
        @media (max-width: 768px) {
          .glass-nav {
            margin: 10px 10px 0;
            padding: 12px 16px;
          }

          .nav-links {
            display: none;
          }

          .nav-cta {
            display: none;
          }

          .nav-hamburger {
            display: flex;
          }

          .nav-mobile-dropdown {
            display: flex;
            flex-direction: column;
            gap: 4px;
            margin-top: 16px;
            padding-top: 16px;
            border-top: 1px solid rgba(255, 255, 255, 0.1);
          }

          .nav-mobile-link {
            display: block;
            padding: 10px 12px;
            color: rgba(255, 255, 255, 0.8);
            text-decoration: none;
            font-size: 15px;
            font-weight: 500;
            border-radius: 8px;
            transition: background 0.2s, color 0.2s;
          }

          .nav-mobile-link:hover,
          .nav-mobile-link.active {
            background: rgba(255, 255, 255, 0.08);
            color: #fff;
          }

          .nav-mobile-cta {
            margin-top: 8px;
            text-decoration: none;
          }
        }
      


      .whitepaper-document {
        color: rgba(255, 255, 255, 0.9);
        line-height: 1.8;
      }

      .whitepaper-document h1 {
        font-size: 32px;
        font-weight: 700;
        margin: 40px 0 20px 0;
        background: linear-gradient(135deg, #8b5cf6, #06b6d4);
        -webkit-background-clip: text;
        -webkit-text-fill-color: transparent;
        line-height: 1.3;
      }

      .whitepaper-document h2 {
        font-size: 24px;
        font-weight: 600;
        margin: 36px 0 16px 0;
        color: #8b5cf6;
        border-bottom: 2px solid rgba(139, 92, 246, 0.3);
        padding-bottom: 8px;
      }

      .whitepaper-document h3 {
        font-size: 18px;
        font-weight: 600;
        margin: 24px 0 12px 0;
        color: #06b6d4;
      }

      .subtitle {
        font-size: 18px;
        color: rgba(255, 255, 255, 0.7);
        margin: 0 0 32px 0;
      }

      .keywords {
        font-size: 14px;
        color: rgba(255, 255, 255, 0.6);
        font-style: italic;
        margin: 16px 0;
      }

      .section-divider {
        border: none;
        border-top: 1px solid rgba(139, 92, 246, 0.2);
        margin: 40px 0;
      }

      .whitepaper-document p {
        margin: 16px 0;
      }

      .whitepaper-document ul, .whitepaper-document ol {
        margin: 16px 0;
        padding-left: 24px;
      }

      .whitepaper-document li {
        margin: 8px 0;
      }

      .whitepaper-document table {
        width: 100%;
        border-collapse: collapse;
        margin: 24px 0;
        background: rgba(255, 255, 255, 0.02);
        border-radius: 8px;
        overflow: hidden;
      }

      .whitepaper-document th {
        background: rgba(139, 92, 246, 0.2);
        color: #fff;
        font-weight: 600;
        padding: 12px 16px;
        text-align: left;
        font-size: 14px;
        text-transform: uppercase;
        letter-spacing: 0.5px;
      }

      .whitepaper-document td {
        padding: 12px 16px;
        border-top: 1px solid rgba(255, 255, 255, 0.05);
      }

      .whitepaper-document tr:hover {
        background: rgba(139, 92, 246, 0.05);
      }

      .whitepaper-document pre {
        background: rgba(0, 0, 0, 0.3);
        padding: 20px;
        border-radius: 8px;
        overflow-x: auto;
        margin: 24px 0;
        border: 1px solid rgba(139, 92, 246, 0.2);
      }

      .whitepaper-document code {
        background: rgba(139, 92, 246, 0.15);
        padding: 2px 8px;
        border-radius: 4px;
        font-family: 'Courier New', monospace;
        font-size: 14px;
        color: rgba(255, 255, 255, 0.95);
      }

      .whitepaper-document pre code {
        background: none;
        padding: 0;
        color: #06b6d4;
      }

      .principle-box, .protocol-box, .theorem-box, .claim-box {
        background: rgba(139, 92, 246, 0.1);
        border-left: 4px solid #8b5cf6;
        padding: 16px 20px;
        margin: 20px 0;
        border-radius: 4px;
      }

      .principle-box p, .protocol-box p, .theorem-box p, .claim-box p {
        margin: 8px 0;
      }

      .document-footer {
        margin: 40px 0;
        padding: 20px;
        background: rgba(255, 255, 255, 0.02);
        border-radius: 8px;
        text-align: center;
      }

      .document-footer p {
        margin: 4px 0;
        font-size: 14px;
      }

      .final-quote {
        background: rgba(0, 0, 0, 0.2);
        border-left: 4px solid #06b6d4;
        padding: 20px;
        margin: 32px 0;
        font-style: italic;
      }

      .final-quote p {
        margin: 8px 0;
      }

      .document-end {
        text-align: center;
        font-weight: 700;
        color: #8b5cf6;
        margin: 40px 0;
        font-size: 18px;
      }

      @media (max-width: 768px) {
        .whitepaper-document h1 {
          font-size: 24px;
        }

        .whitepaper-document h2 {
          font-size: 20px;
        }

        .whitepaper-document h3 {
          font-size: 16px;
        }

        .whitepaper-document table {
          font-size: 14px;
        }

        .whitepaper-document th, .whitepaper-document td {
          padding: 8px 12px;
        }
      }
    


          /* Cosmic Page Layout */
          .cosmic-page {
            position: relative;
            min-height: 100vh;
            overflow-x: hidden;
          }

          .content-layer {
            position: relative;
            z-index: 10;
            padding: 0;
          }

          /* Glassmorphism Effect */
          .glass {
            background: rgba(255, 255, 255, 0.03);
            backdrop-filter: blur(20px);
            border: 1px solid rgba(255, 255, 255, 0.1);
            box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
          }

                    /* Back Button */
          .back-button {
            margin: 20px;
            padding: 20px 32px;
            border-radius: 16px;
          }

          .back-btn {
            background: none;
            border: none;
            color: rgba(255, 255, 255, 0.8);
            font-size: 16px;
            font-weight: 500;
            cursor: pointer;
            transition: color 0.2s;
          }

          .back-btn:hover {
            color: #fff;
          }

          /* Whitepaper Header */
          .whitepaper-header-section {
            margin: 20px;
            padding: 60px 48px;
            border-radius: 24px;
            text-align: center;
          }

          .whitepaper-title-main {
            font-size: 48px;
            font-weight: 800;
            color: #fff;
            margin-bottom: 20px;
            line-height: 1.2;
            text-shadow: 0 2px 12px rgba(0, 0, 0, 0.6);
          }

          .whitepaper-meta-main {
            display: flex;
            gap: 24px;
            justify-content: center;
            font-size: 16px;
            color: rgba(255, 255, 255, 0.7);
            margin-bottom: 24px;
          }

          .whitepaper-topics {
            display: flex;
            flex-wrap: wrap;
            gap: 12px;
            justify-content: center;
            margin-bottom: 32px;
          }

          .topic-badge {
            padding: 8px 16px;
            background: rgba(139, 92, 246, 0.2);
            border: 1px solid rgba(139, 92, 246, 0.4);
            color: rgba(255, 255, 255, 0.9);
            border-radius: 8px;
            font-size: 14px;
            font-weight: 600;
          }

          /* Whitepaper Content */
          .whitepaper-content {
            margin: 40px 20px;
            padding: 80px 48px;
            border-radius: 24px;
          }

          .whitepaper-content .container {
            max-width: 900px;
            margin: 0 auto;
          }

          .markdown-content {
            color: rgba(255, 255, 255, 0.9);
            line-height: 1.8;
          }

          /* Authorship block — who published this specification */
          .markdown-content .paper-authorship {
            font-size: 13.5px;
            line-height: 1.85;
            color: rgba(255, 255, 255, 0.62);
            border-left: 2px solid rgba(139, 92, 246, 0.55);
            padding: 4px 0 4px 18px;
            margin: 22px 0 0;
          }

          .markdown-content .paper-authorship strong {
            color: rgba(255, 255, 255, 0.92);
            letter-spacing: 0.02em;
          }

          /* Citation block — how to reference this document */
          .markdown-content .paper-citation {
            font-size: 12.5px;
            line-height: 1.8;
            color: rgba(255, 255, 255, 0.45);
            margin: 8px 0 0;
          }

          .markdown-content .paper-citation strong {
            color: rgba(255, 255, 255, 0.7);
          }

          /* Cross-paper links — AETHERION internal navigation */
          .markdown-content a {
            color: #8b5cf6;
            text-decoration: none;
            border-bottom: 1px solid rgba(139, 92, 246, 0.35);
            transition: color 0.18s ease, border-color 0.18s ease;
          }

          .markdown-content a:hover {
            color: #06b6d4;
            border-bottom-color: rgba(6, 182, 212, 0.7);
          }

          /* Related-papers navigation block */
          .related-papers {
            margin: 56px 0 8px;
            padding: 28px 32px;
            border: 1px solid rgba(139, 92, 246, 0.25);
            border-radius: 16px;
            background: rgba(139, 92, 246, 0.05);
          }

          .related-papers h3 {
            font-size: 13px;
            font-weight: 700;
            letter-spacing: 0.16em;
            text-transform: uppercase;
            color: rgba(255, 255, 255, 0.55);
            margin: 0 0 18px;
          }

          .related-papers ul {
            list-style: none;
            padding: 0;
            margin: 0;
            display: grid;
            gap: 14px;
          }

          .related-papers li {
            padding: 0;
            margin: 0;
          }

          .related-papers a {
            font-weight: 600;
            border-bottom: none;
          }

          .related-papers .rel-role {
            display: block;
            font-size: 14px;
            color: rgba(255, 255, 255, 0.6);
            font-weight: 400;
            margin-top: 3px;
          }

          .markdown-content h1 {
            font-size: 40px;
            font-weight: 800;
            color: #fff;
            margin: 48px 0 24px;
            text-shadow: 0 2px 8px rgba(0, 0, 0, 0.4);
          }

          .markdown-content h2 {
            font-size: 32px;
            font-weight: 700;
            color: #fff;
            margin: 40px 0 20px;
            text-shadow: 0 2px 6px rgba(0, 0, 0, 0.4);
          }

          .markdown-content h3 {
            font-size: 24px;
            font-weight: 600;
            color: rgba(255, 255, 255, 0.95);
            margin: 32px 0 16px;
          }

          .markdown-content p {
            margin: 16px 0;
            color: rgba(255, 255, 255, 0.85);
          }

          .markdown-content strong {
            color: #fff;
            font-weight: 700;
          }

          .markdown-content li {
            margin: 8px 0;
            margin-left: 24px;
            color: rgba(255, 255, 255, 0.85);
          }

          .markdown-content hr {
            border: none;
            border-top: 1px solid rgba(255, 255, 255, 0.1);
            margin: 40px 0;
          }

          .table-line {
            font-family: monospace;
            font-size: 14px;
            color: rgba(255, 255, 255, 0.8);
            margin: 2px 0;
          }

          /* Footer */
          .footer {
            margin: 40px 20px;
            padding: 60px 48px;
            border-radius: 24px;
          }

          .footer-card {
            max-width: 1200px;
            margin: 0 auto;
          }

          .footer-content {
            display: grid;
            grid-template-columns: repeat(5, 1fr);
            gap: 48px;
            margin-bottom: 48px;
          }

          .footer-section h3 {
            font-size: 24px;
            font-weight: 800;
            margin-bottom: 8px;
            background: linear-gradient(135deg, #8b5cf6 0%, #6366f1 100%);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
          }

          .footer-tagline {
            font-size: 14px;
            color: rgba(255, 255, 255, 0.6);
          }

          .footer-section h4 {
            font-size: 16px;
            font-weight: 700;
            margin-bottom: 16px;
            color: #fff;
          }

          .footer-links {
            list-style: none;
            padding: 0;
            margin: 0;
          }

          .footer-links li {
            margin-bottom: 12px;
          }

          .footer-links a {
            color: rgba(255, 255, 255, 0.7);
            text-decoration: none;
            font-size: 15px;
            transition: color 0.2s;
          }

          .footer-links a:hover {
            color: #8b5cf6;
          }

          .footer-bottom {
            text-align: center;
            padding-top: 32px;
            border-top: 1px solid rgba(255, 255, 255, 0.1);
            color: rgba(255, 255, 255, 0.5);
            font-size: 14px;
          }

          /* Mobile Responsive */
          @media (max-width: 968px) {
            .footer-content {
              grid-template-columns: repeat(2, 1fr);
              gap: 32px;
            }

            .whitepaper-title-main {
              font-size: 32px;
            }
          }

          @media (max-width: 768px) {
            .whitepaper-content {
              padding: 40px 24px;
            }

            .footer-content {
              grid-template-columns: 1fr;
              gap: 24px;
            }
          }