/* CSS Variables for a refined, general niche aesthetic */
        :root {
            --primary: #2563eb;
            --primary-hover: #1d4ed8;
            --bg: #ffffff;
            --surface: #f8fafc;
            --text-main: #1e293b;
            --text-muted: #64748b;
            --border: #e2e8f0;
            --max-width: 1100px;
            --content-width: 720px;
            --system-fonts: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji";
        }

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

        body {
            font-family: var(--system-fonts);
            line-height: 1.625;
            color: var(--text-main);
            background-color: var(--bg);
            -webkit-font-smoothing: antialiased;
        }

        /* Layout Structure */
        header {
            border-bottom: 1px solid var(--border);
            padding: 1.5rem 0;
            background: var(--bg);
            z-index: 100;
        }

        .container {
            max-width: var(--max-width);
            margin: 0 auto;
            padding: 0 1.5rem;
        }

        nav {
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .logo {
            font-weight: 800;
            font-size: 1.25rem;
            color: var(--primary);
            text-decoration: none;
        }

        .nav-links {
            display: flex;
            gap: 2rem;
            list-style: none;
        }

        .nav-links a {
            text-decoration: none;
            color: var(--text-main);
            font-weight: 500;
            font-size: 0.9rem;
            transition: color 0.2s;
        }

        .nav-links a:hover {
            color: var(--primary);
        }

        .mobile-menu-toggle {
            display: none;
            background: none;
            border: none;
            cursor: pointer;
            padding: 0.5rem;
        }

        /* Main Content Grid */
        .main-grid {
            display: grid;
            grid-template-columns: 1fr 300px;
            gap: 3rem;
            margin-top: 3rem;
        }

        /* Article Styling */
        article {
            max-width: var(--content-width);
        }

        .meta {
            font-size: 0.875rem;
            color: var(--text-muted);
            margin-bottom: 1rem;
            display: flex;
            gap: 1rem;
        }

        h1 {
            font-size: clamp(2rem, 5vw, 3rem);
            line-height: 1.1;
            font-weight: 800;
            letter-spacing: -0.02em;
            margin-bottom: 1.5rem;
        }

        .lead {
            font-size: 1.25rem;
            color: var(--text-muted);
            margin-bottom: 2rem;
        }

        .featured-image-container {
            margin-bottom: 2.5rem;
            border-radius: 12px;
            overflow: hidden;
            background: var(--surface);
        }

        .featured-image-container img {
            width: 100%;
            height: auto;
            display: block;
        }

        .article-body {
            font-size: 1.125rem;
        }

        .article-body h2 {
            font-size: 1.75rem;
            margin: 2.5rem 0 1rem;
            font-weight: 700;
            scroll-margin-top: 2rem;
        }

        .article-body h3 {
            font-size: 1.4rem;
            margin: 2rem 0 1rem;
            font-weight: 600;
        }

        .article-body p {
            margin-bottom: 1.5rem;
        }

        /* Tables & Responsive Wrapper */
        .table-wrapper {
            overflow-x: auto;
            margin: 2rem 0;
            border: 1px solid var(--border);
            border-radius: 8px;
        }

        table {
            width: 100%;
            border-collapse: collapse;
            font-size: 0.95rem;
            min-width: 500px;
        }

        th {
            background: var(--surface);
            text-align: left;
            padding: 0.75rem 1rem;
            border-bottom: 1px solid var(--border);
        }

        td {
            padding: 0.75rem 1rem;
            border-bottom: 1px solid var(--border);
        }

        /* Sidebar - Table of Contents */
        aside {
            position: sticky;
            top: 2rem;
            height: fit-content;
        }

        .toc-container {
            padding: 1.5rem;
            background: var(--surface);
            border-radius: 12px;
        }

        .toc-title {
            font-weight: 700;
            font-size: 0.875rem;
            text-transform: uppercase;
            letter-spacing: 0.05em;
            margin-bottom: 1rem;
            color: var(--text-muted);
        }

        #toc-list {
            list-style: none;
        }

        #toc-list li {
            margin-bottom: 0.75rem;
        }

        #toc-list a {
            text-decoration: none;
            color: var(--text-main);
            font-size: 0.9rem;
            transition: color 0.2s;
            display: block;
        }

        #toc-list a:hover {
            color: var(--primary);
        }

        #toc-list a.active {
            color: var(--primary);
            font-weight: 600;
        }

        /* Footer */
        footer {
            margin-top: 5rem;
            padding: 4rem 0;
            border-top: 1px solid var(--border);
            background: var(--surface);
            color: var(--text-muted);
            text-align: center;
        }

        /* Mobile Adjustments */
        @media (max-width: 900px) {
            .main-grid {
                grid-template-columns: 1fr;
            }
            aside {
                display: none; /* Hide TOC on mobile for brevity or move below header */
            }
            .nav-links {
                display: none; /* Hidden for mobile toggle */
                position: absolute;
                top: 100%;
                left: 0;
                right: 0;
                background: #fff;
                flex-direction: column;
                padding: 1.5rem;
                border-bottom: 1px solid var(--border);
                gap: 1rem;
                box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
            }
            .nav-links.show {
                display: flex;
            }
            .mobile-menu-toggle {
                display: block;
            }
        }