/* Base Styles */
        :root {
            --primary-color: #2a5bd7;
            --primary-hover: #1e4bc5;
            --text-primary: #1a1a1a;
            --text-secondary: #4d4d4d;
            --text-tertiary: #808080;
            --bg-color: #ffffff;
            --bg-secondary: #f8f9fa;
            --border-color: #e0e0e0;
            --max-width: 800px;
            --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
            --font-serif: "Georgia", serif;
            --font-mono: "SF Mono", "Menlo", monospace;
            --transition: all 0.3s cubic-bezier(0.645, 0.045, 0.355, 1);
        }

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

        body {
            font-family: var(--font-sans);
            color: var(--text-primary);
            background-color: var(--bg-color);
            line-height: 1.6;
            -webkit-font-smoothing: antialiased;
            text-rendering: optimizeLegibility;
        }

        /* Loading Screen */
        .loading-screen {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background-color: var(--bg-color);
            display: flex;
            justify-content: center;
            align-items: center;
            z-index: 9999;
            transition: opacity 0.8s ease-out;
        }

        .loading-content {
            text-align: center;
            display: flex;
            flex-direction: column;
            align-items: center;
        }

        .progress-bar {
            width: 200px;
            height: 2px;
            background-color: rgba(0, 0, 0, 0.1);
            border-radius: 1px;
            overflow: hidden;
            margin-bottom: 24px;
        }

        .progress {
            height: 100%;
            width: 0;
            background-color: var(--primary-color);
            transition: width 0.3s ease;
        }

        .loading-text {
            font-size: 16px;
            font-weight: 400;
            color: var(--text-secondary);
            letter-spacing: 0.5px;
            margin-bottom: 24px;
        }

        /* Layout */
        .container {
            max-width: var(--max-width);
            margin: 0 auto;
            padding: 0 24px;
        }

        /* Typography */
        h1, h2, h3, h4, h5, h6 {
            font-weight: 600;
            line-height: 1.3;
            margin-bottom: 1em;
            color: var(--text-primary);
        }

        h1 {
            font-size: 2.5rem;
            margin-bottom: 1.5rem;
        }

        h2 {
            font-size: 1.75rem;
            margin-top: 3rem;
        }

        h3 {
            font-size: 1.25rem;
            margin-top: 2rem;
        }

        p {
            margin-bottom: 1.5rem;
            font-size: 1.125rem;
            line-height: 1.8;
            color: var(--text-secondary);
        }

        a {
            color: var(--primary-color);
            text-decoration: none;
            transition: var(--transition);
        }

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

        /* Navigation */
        nav {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            padding: 24px 0;
            z-index: 100;
            background-color: rgba(255, 255, 255, 0.98);
            border-bottom: 1px solid var(--border-color);
        }

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

        .logo {
            font-size: 1.5rem;
            font-weight: 700;
            letter-spacing: -0.5px;
        }

        .logo span {
            color: var(--primary-color);
        }

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

        .nav-links li {
            margin-left: 32px;
        }

        .nav-links a {
            font-weight: 500;
            color: var(--text-primary);
            text-decoration: none;
        }

        .nav-links a:hover {
            color: var(--primary-color);
            text-decoration: none;
        }

        /* Article */
        .article-header {
            padding: 120px 0 60px;
        }

        .article-meta {
            display: flex;
            align-items: center;
            margin-bottom: 24px;
            font-size: 0.875rem;
            color: var(--text-tertiary);
        }

        .article-meta span {
            margin-right: 16px;
        }

        .article-meta .category {
            color: var(--primary-color);
            font-weight: 500;
        }

        .article-content {
            padding: 60px 0;
        }

        .article-content p {
            margin-bottom: 2rem;
        }

        blockquote {
            border-left: 4px solid var(--primary-color);
            padding-left: 24px;
            margin: 2rem 0;
            font-style: italic;
            color: var(--text-primary);
        }

        /* Footer */
        footer {
            padding: 60px 0;
            border-top: 1px solid var(--border-color);
            margin-top: 60px;
        }

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

        .footer-links a {
            margin-left: 24px;
            color: var(--text-secondary);
        }

        .copyright {
            color: var(--text-tertiary);
            font-size: 0.875rem;
        }

        /* Back Button */
        .back-button {
            position: fixed;
            bottom: 30px;
            left: 30px;
            width: 50px;
            height: 50px;
            background-color: var(--primary-color);
            color: white;
            border-radius: 50%;
            display: flex;
            justify-content: center;
            align-items: center;
            cursor: pointer;
            box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
            transition: var(--transition);
            z-index: 99;
        }

        .back-button:hover {
            background-color: var(--primary-hover);
            transform: translateY(-2px);
            box-shadow: 0 6px 16px rgba(0, 0, 0, 0.2);
        }

        .back-button i {
            font-size: 20px;
        }

        /* Animations */
        @keyframes fadeIn {
            from { opacity: 0; }
            to { opacity: 1; }
        }

        /* Responsive */
        @media (max-width: 768px) {
            h1 {
                font-size: 2rem;
            }
            
            .nav-links {
                display: none;
            }
            
            .article-header {
                padding: 100px 0 40px;
            }
            
            .footer-content {
                flex-direction: column;
                text-align: center;
            }
            
            .footer-links {
                margin-top: 24px;
            }
            
            .footer-links a {
                margin: 0 12px;
            }

            .back-button {
                bottom: 20px;
                left: 20px;
                width: 45px;
                height: 45px;
            }
        }