*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

        :root {
            --navy: #1a1a2e;
            --navy-light: #16213e;
            --accent: #155DFC;
            --accent-hover: #1249d6;
            --accent-light: #e8efff;
            --text-primary: #1a1a2e;
            --text-secondary: #4a4a68;
            --text-muted: #7a7a96;
            --surface: #ffffff;
            --surface-alt: #f8f9fc;
            --border: #e2e4eb;
            --radius: 10px;
            --radius-lg: 16px;
        }

        body {
            font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
            color: var(--text-primary);
            line-height: 1.7;
            background: var(--surface-alt);
            -webkit-font-smoothing: antialiased;
        }

        /* Header */
        .header {
            background: var(--navy);
            padding: 0 24px;
            position: sticky;
            top: 0;
            z-index: 100;
            box-shadow: 0 2px 16px rgba(0, 0, 0, 0.15);
        }

        .header-inner {
            max-width: 1120px;
            margin: 0 auto;
            display: flex;
            align-items: center;
            justify-content: space-between;
            height: 68px;
        }

        .logo {
            display: flex;
            align-items: center;
            gap: 10px;
            text-decoration: none;
            color: #fff;
            font-weight: 800;
            font-size: 22px;
            letter-spacing: -0.02em;
        }

        .logo-icon {
            width: 36px;
            height: 36px;
            background: var(--accent);
            border-radius: 8px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 18px;
            font-weight: 700;
            color: #fff;
            position: relative;
            overflow: hidden;
        }

        .logo-icon::after {
            content: '';
            position: absolute;
            top: 0; left: 0; right: 0; bottom: 0;
            background: linear-gradient(135deg, rgba(255,255,255,0.15) 0%, transparent 60%);
        }

        .nav-links {
            display: flex;
            gap: 8px;
            list-style: none;
        }

        .nav-links a {
            color: rgba(255, 255, 255, 0.75);
            text-decoration: none;
            font-size: 14px;
            font-weight: 500;
            padding: 8px 16px;
            border-radius: 6px;
            transition: color 0.2s, background 0.2s;
        }

        .nav-links a:hover {
            color: #fff;
            background: rgba(255, 255, 255, 0.08);
        }

        .mobile-toggle {
            display: none;
            background: none;
            border: none;
            color: #fff;
            font-size: 24px;
            cursor: pointer;
            padding: 8px;
        }

        /* Container */
        .container {
            max-width: 780px;
            margin: 0 auto;
            padding: 48px 24px 80px;
        }

        h1 {
            font-size: 2rem;
            font-weight: 800;
            color: var(--text-primary);
            margin-bottom: 8px;
        }

        .updated {
            font-size: 0.9rem;
            color: var(--text-muted);
            margin-bottom: 40px;
        }

        h2 {
            font-size: 1.4rem;
            font-weight: 700;
            color: var(--text-primary);
            margin-top: 40px;
            margin-bottom: 12px;
            padding-bottom: 8px;
            border-bottom: 2px solid var(--border);
        }

        h3 {
            font-size: 1.1rem;
            font-weight: 600;
            color: var(--text-primary);
            margin-top: 24px;
            margin-bottom: 10px;
        }

        p, li {
            font-size: 1rem;
            margin-bottom: 14px;
            color: var(--text-secondary);
            line-height: 1.75;
        }

        ul, ol {
            padding-left: 24px;
            margin-bottom: 16px;
        }

        li {
            margin-bottom: 8px;
        }

        a {
            color: var(--accent);
            text-decoration: none;
            transition: color 0.2s;
        }

        a:hover {
            color: var(--accent-hover);
            text-decoration: underline;
        }

        strong {
            color: var(--text-primary);
        }

        .toc {
            background: var(--surface);
            border: 1px solid var(--border);
            border-radius: var(--radius);
            padding: 24px 28px;
            margin-bottom: 32px;
        }

        .toc h3 {
            margin-top: 0;
            font-size: 15px;
            font-weight: 700;
            color: var(--text-primary);
            margin-bottom: 12px;
        }

        .toc ol {
            padding-left: 20px;
            margin-bottom: 0;
        }

        .toc li {
            font-size: 14px;
            margin-bottom: 6px;
        }

        .toc a {
            font-weight: 500;
        }

        .highlight-box {
            background: var(--accent-light);
            border-left: 4px solid var(--accent);
            border-radius: 0 var(--radius) var(--radius) 0;
            padding: 18px 22px;
            margin: 24px 0;
        }

        .highlight-box p {
            color: var(--text-primary);
            margin-bottom: 0;
            font-size: 15px;
        }

        /* Footer */
        .footer {
            background: var(--navy);
            color: rgba(255, 255, 255, 0.5);
            padding: 48px 24px 36px;
        }

        .footer-inner {
            max-width: 1120px;
            margin: 0 auto;
        }

        .footer-top {
            display: flex;
            justify-content: space-between;
            align-items: flex-start;
            margin-bottom: 36px;
            gap: 32px;
        }

        .footer-brand p {
            font-size: 13px;
            line-height: 1.65;
            max-width: 340px;
            margin-top: 12px;
        }

        .footer-links-group h4 {
            color: rgba(255, 255, 255, 0.8);
            font-size: 13px;
            font-weight: 700;
            text-transform: uppercase;
            letter-spacing: 0.06em;
            margin-bottom: 14px;
        }

        .footer-links-group ul { list-style: none; }
        .footer-links-group li { margin-bottom: 8px; }

        .footer-links-group a {
            color: rgba(255, 255, 255, 0.5);
            text-decoration: none;
            font-size: 14px;
            transition: color 0.2s;
        }

        .footer-links-group a:hover { color: #fff; }

        .footer-divider {
            border: none;
            border-top: 1px solid rgba(255, 255, 255, 0.08);
            margin-bottom: 24px;
        }

        .footer-bottom {
            display: flex;
            justify-content: space-between;
            align-items: center;
            flex-wrap: wrap;
            gap: 12px;
            font-size: 12px;
        }

        .footer-bottom a {
            color: rgba(255, 255, 255, 0.45);
            text-decoration: none;
            transition: color 0.2s;
        }

        .footer-bottom a:hover { color: rgba(255, 255, 255, 0.8); }

        .footer-disclaimer {
            font-size: 11px;
            line-height: 1.65;
            color: rgba(255, 255, 255, 0.3);
            max-width: 1120px;
            margin: 20px auto 0;
            text-align: center;
        }

        /* Mobile */
        @media (max-width: 768px) {
            .mobile-toggle { display: block; }

            .nav-links {
                display: none;
                position: absolute;
                top: 68px; left: 0; right: 0;
                background: var(--navy);
                flex-direction: column;
                padding: 12px 24px 20px;
                border-top: 1px solid rgba(255, 255, 255, 0.06);
                box-shadow: 0 8px 24px rgba(0, 0, 0, 0.2);
            }

            .nav-links.open { display: flex; }
            .nav-links a { padding: 12px 16px; }

            .container { padding: 36px 20px 64px; }

            h1 { font-size: 1.6rem; }

            .footer-top { flex-direction: column; }
        }
    
        /* Dark Mode */
        [data-theme="dark"] { --navy: #0d0d1a; --navy-light: #0a0f1e; --text-primary: #e4e4e8; --text-secondary: #a0a0b8; --text-muted: #6a6a86; --surface: #1a1a2e; --surface-alt: #16213e; --border: #2a2a4e; --accent: #4d8aff; --accent-hover: #3a75e8; --accent-light: #1a2a4e; }
        [data-theme="dark"] body { background: #1a1a2e; color: #e4e4e8; }
        [data-theme="dark"] .ftc-banner { background: #16213e; border-color: #2a2a4e; color: #6a6a86; }
        [data-theme="dark"] img { opacity: 0.9; }