/* CSS Variables & Reset */
        :root {
            --primary: #2563eb;
            /* Royal Blue */
            --primary-dark: #1e40af;
            --text-main: #111827;
            /* Dark Grey */
            --text-light: #4b5563;
            /* Light Grey */
            --bg-body: #ffffff;
            --bg-subtle: #f9fafb;
            /* Very light grey */
            --border: #e5e7eb;
            --max-width: 1140px;
            --font-stack: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
        }

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

        body {
            font-family: var(--font-stack);
            color: var(--text-main);
            line-height: 1.65;
            background-color: var(--bg-body);
            -webkit-font-smoothing: antialiased;
        }

        a {
            color: var(--primary);
            text-decoration: none;
            font-weight: 500;
            transition: 0.2s;
        }

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

        img {
            max-width: 100%;
            height: auto;
            display: block;
            border-radius: 8px;
        }

        /* Container */
        .container {
            max-width: var(--max-width);
            margin: 0 auto;
            padding: 0 16px;
        }

        /* 1. Breadcrumb */
        .breadcrumb {
            margin: 20px 0 15px;
            font-size: 0.9rem;
            color: var(--text-light);
            white-space: nowrap;
            overflow: hidden;
            text-overflow: ellipsis;
        }

        .breadcrumb a {
            color: var(--text-light);
        }

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

        .sep {
            margin: 0 8px;
            color: #ccc;
        }

        .curr {
            color: var(--text-main);
            font-weight: 600;
        }

        /* 2. Header */
        .article-header h1 {
            font-size: 1.8rem;
            line-height: 1.3;
            font-weight: 800;
            margin-bottom: 12px;
            color: #111;
        }

        .meta-info {
            display: flex;
            flex-wrap: wrap;
            align-items: center;
            gap: 12px;
            font-size: 0.9rem;
            color: var(--text-light);
            margin-bottom: 20px;
            border-bottom: 1px solid var(--border);
            padding-bottom: 16px;
        }

        .read-time {
            background: var(--bg-subtle);
            padding: 2px 8px;
            border-radius: 4px;
            font-size: 0.85rem;
            font-weight: 600;
        }

        /* 3. Hero Image (No Overlay) */
        .hero-container {
            width: 100%;
            margin-bottom: 30px;
            border-radius: 10px;
            overflow: hidden;
            box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
            background: #f0f0f0;
        }

        .hero-container img {
            width: 100%;
            height: auto;
            object-fit: cover;
            aspect-ratio: 16/9;
            /* Enforce ratio */
        }

        /* 4. Layout Grid */
        .content-wrapper {
            display: flex;
            flex-direction: column;
            /* Mobile Default */
            gap: 40px;
            margin-bottom: 60px;
        }

        /* Main Content Styling */
        .main-article {
            width: 100%;
        }

        .main-article p {
            margin-bottom: 1.2rem;
            font-size: 1.05rem;
        }

        .main-article h2 {
            font-size: 1.5rem;
            margin: 2rem 0 1rem;
            padding-bottom: 8px;
            border-bottom: 2px solid var(--bg-subtle);
            color: #000;
        }

        .main-article h3 {
            font-size: 1.25rem;
            margin: 1.5rem 0 0.8rem;
        }

        .main-article ul,
        .main-article ol {
            margin-bottom: 1.2rem;
            padding-left: 20px;
        }

        .main-article li {
            margin-bottom: 6px;
        }

        /* --- Table of Contents Box (Visible) --- */
        .toc-box {
            background: #f8fafc;
            border: 1px solid #e2e8f0;
            border-radius: 8px;
            padding: 20px;
            margin: 24px 0;
        }

        .toc-title {
            font-weight: 700;
            font-size: 1.1rem;
            margin-bottom: 12px;
            color: var(--text-main);
            display: block;
        }

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

        .toc-list li {
            margin-bottom: 8px;
            border-bottom: 1px solid #eee;
            padding-bottom: 8px;
        }

        .toc-list li:last-child {
            border: none;
            padding-bottom: 0;
        }

        .toc-list a {
            color: var(--text-light);
            font-size: 0.95rem;
            display: block;
        }

        .toc-list a:hover {
            color: var(--primary);
            padding-left: 4px;
        }

        /* --- Responsive Tables --- */
        .table-scroll {
            overflow-x: auto;
            /* Enable horizontal scroll */
            -webkit-overflow-scrolling: touch;
            /* Smooth scroll on iOS */
            margin: 20px 0;
            border: 1px solid var(--border);
            border-radius: 8px;
            box-shadow: 0 2px 4px rgba(0, 0, 0, 0.02);
        }

        table {
            width: 100%;
            border-collapse: collapse;
            min-width: 600px;
            /* Force table to be wide enough to scroll on mobile */
        }

        th,
        td {
            padding: 14px;
            text-align: left;
            border-bottom: 1px solid var(--border);
            white-space: nowrap;
            /* Prevent text wrapping */
        }

        th {
            background: #f1f5f9;
            font-weight: 600;
            color: #333;
        }

        tr:nth-child(even) {
            background: #fafafa;
        }

        tr:last-child td {
            border-bottom: none;
        }

        /* Highlights */
        .highlight-box {
            background: #eff6ff;
            border-left: 4px solid var(--primary);
            padding: 16px;
            margin: 24px 0;
            border-radius: 0 6px 6px 0;
        }

        /* FAQ */
        details.faq-item {
            border: 1px solid var(--border);
            border-radius: 6px;
            padding: 12px 16px;
            margin-bottom: 10px;
            background: #fff;
        }

        summary {
            font-weight: 600;
            cursor: pointer;
            outline: none;
        }

        details[open] summary {
            margin-bottom: 10px;
            color: var(--primary);
        }

        /* Sidebar (Desktop Only) */
        .sidebar {
            display: none;
            /* Hidden on Mobile */
        }

        .widget {
            background: #fff;
            border: 1px solid var(--border);
            border-radius: 8px;
            padding: 20px;
            margin-bottom: 24px;
        }

        .widget h4 {
            font-size: 0.95rem;
            text-transform: uppercase;
            letter-spacing: 0.5px;
            border-bottom: 2px solid var(--bg-subtle);
            padding-bottom: 10px;
            margin-bottom: 15px;
        }

        .widget ul {
            list-style: none;
            padding: 0;
        }

        .widget li {
            margin-bottom: 10px;
        }

        /* Footer */
        footer {
            background: #111;
            color: #999;
            text-align: center;
            padding: 40px 16px;
            margin-top: 40px;
            font-size: 0.9rem;
        }

        /* --- RESPONSIVE MEDIA QUERIES --- */
        @media (min-width: 768px) {
            .container {
                padding: 0 24px;
            }

            .article-header h1 {
                font-size: 2.5rem;
            }
        }

        @media (min-width: 1024px) {
            .content-wrapper {
                display: grid;
                grid-template-columns: 1fr 320px;
                /* Article | Sidebar */
                align-items: start;
            }

            .sidebar {
                display: block;
                /* Show Sidebar */
                position: sticky;
                top: 20px;
            }
        }