/* ------------------------- */
        /* ---  Root & Setup     --- */
        /* ------------------------- */
        :root {
            /* Consistent Color Palette */
            --bg-color: #f8f9fa;
            --card-bg: #ffffff;
            --text-primary: #212529;
            --text-secondary: #6c757d;
            --accent-color: #007bff;
            --border-color: #dee2e6;

            /* Typography & Sizing */
            --font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
            --border-radius: 8px;
        }

        /* Dark Mode Preferences */
        @media (prefers-color-scheme: dark) {
            :root {
                --bg-color: #121212;
                --card-bg: #1e1e1e;
                --text-primary: #e9ecef;
                --text-secondary: #adb5bd;
                --accent-color: #3391ff;
                --border-color: #495057;
            }
        }

        /* Basic Reset & Body Styles */
        * {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
        }

        body {
            font-family: var(--font-family);
            background-color: var(--bg-color);
            color: var(--text-primary);
            line-height: 1.7;
        }
        
        /* ------------------------- */
        /* --- Layout & Header   --- */
        /* ------------------------- */
        .site-header {
            padding: 1rem 1.5rem;
            border-bottom: 1px solid var(--border-color);
            background-color: var(--card-bg);
        }

        .nav-container {
            max-width: 800px;
            margin: 0 auto;
        }

        .back-link {
            display: inline-flex;
            align-items: center;
            gap: 0.5rem;
            text-decoration: none;
            font-weight: 500;
            color: var(--accent-color);
            transition: opacity 0.2s;
        }

        .back-link:hover {
            opacity: 0.8;
        }

        #toc li a{
            color:white;
        }

        /* ------------------------- */
        /* --- Article Content   --- */
        /* ------------------------- */
        main {
            padding: 2rem 1.5rem;
        }
        
        .article-container {
            max-width: 800px;
            margin: 0 auto;
        }
        
        .article-header h1 {
            font-size: 2.5rem;
            line-height: 1.2;
            margin-bottom: 0.5rem;
        }
        
        .article-meta {
            color: var(--text-secondary);
            font-size: 1rem;
            margin-bottom: 2rem;
            border-bottom: 1px solid var(--border-color);
            padding-bottom: 2rem;
        }

        .article-content h2 {
            font-size: 1.75rem;
            margin-top: 2.5rem;
            margin-bottom: 1rem;
            padding-bottom: 0.5rem;
            border-bottom: 1px solid var(--border-color);
        }
        
        .article-content h3 {
            font-size: 1.25rem;
            margin-top: 2rem;
            margin-bottom: 0.75rem;
            color: var(--text-primary);
        }

        .article-content p {
            margin-bottom: 1.5rem;
        }
        
        .article-content ul {
            list-style-position: inside;
            padding-left: 0.5rem;
            margin-bottom: 1.5rem;
        }
        
        .article-content li {
            margin-bottom: 0.5rem;
        }

        /* ------------------------- */
        /* ---      Footer       --- */
        /* ------------------------- */
        .site-footer {
            text-align: center;
            padding: 2rem 1.5rem;
            margin-top: 2rem;
            border-top: 1px solid var(--border-color);
            color: var(--text-secondary);
        }
        
        .site-footer a {
            color: var(--accent-color);
            text-decoration: none;
        }
        
        .site-footer a:hover {
            text-decoration: underline;
        }
        
        /* ------------------------- */
        /* ---   Responsiveness  --- */
        /* ------------------------- */
        @media (max-width: 768px) {
            .article-header h1 {
                font-size: 2rem;
            }
            .article-content h2 {
                font-size: 1.5rem;
            }
        }
        .site-header {
            position: sticky;
            top: 0;
            z-index: 1000;
            transition: transform 0.3s ease;
        }