/* CSS Variables */
        :root {
            --primary-color: #667eea;
            --primary-hover: #5a67d8;
            --secondary-color: #48bb78;
            --bg-color: #ffffff;
            --card-bg: #ffffff;
            --text-primary: #2d3748;
            --text-secondary: #718096;
            --border-color: #e2e8f0;
            --hover-bg: #edf2f7;
            --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
            --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
            --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
        }

        /* Dark Theme */
        body.dark-theme {
            --bg-color: #1a202c;
            --card-bg: #2d3748;
            --text-primary: #f7fafc;
            --text-secondary: #a0aec0;
            --border-color: #4a5568;
            --hover-bg: #374151;
        }

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

        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
            background-color: var(--bg-color);
            color: var(--text-primary);
            line-height: 1.6;
            transition: background-color 0.3s ease, color 0.3s ease;
        }

        .site-container {
            min-height: 100vh;
            display: flex;
            flex-direction: column;
        }

        /* Header */
        .app-header {
            background: var(--card-bg);
            border-bottom: 1px solid var(--border-color);
            box-shadow: var(--shadow);
        }

        .header-content {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 1rem 2rem;
            max-width: 1400px;
            margin: 0 auto;
        }

        .logo {
            display: flex;
            align-items: center;
            gap: 0.75rem;
            text-decoration: none;
        }

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

        .logo span {
            font-size: 1.5rem;
            font-weight: 700;
            background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
        }

        .header-nav {
            display: flex;
            gap: 1rem;
            align-items: center;
        }

        .header-nav a {
            color: var(--text-secondary);
            text-decoration: none;
            font-weight: 500;
            transition: color 0.3s;
        }

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

        .theme-toggle {
            background: var(--hover-bg);
            border: 1px solid var(--border-color);
            border-radius: 12px;
            width: 44px;
            height: 44px;
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            transition: all 0.2s ease;
            color: var(--text-secondary);
        }

        .theme-toggle:hover {
            background: var(--primary-color);
            color: white;
            transform: translateY(-2px);
        }

        /* Hero */
        .hero {
            background: var(--hover-bg);
            padding: 4rem 1rem;
            text-align: center;
        }

        .hero-content h1 {
            font-size: 2.5rem;
            margin-bottom: 1rem;
            color: var(--text-primary);
        }

        .hero-content p {
            font-size: 1.125rem;
            color: var(--text-secondary);
            max-width: 600px;
            margin: 0 auto;
        }

        /* Tools Grid */
        .tools-grid-container {
            flex: 1;
            padding: 3rem 1rem;
            max-width: 1400px;
            margin: 0 auto;
            width: 100%;
        }

        .tools-grid {
            display: grid;
            grid-template-columns: repeat(4, 250px);
            gap: 2rem;
            justify-content: center;
        }

        /* Tool Card */
        .tool-card {
            width: 250px;
            height: 300px;
            background: var(--card-bg);
            border: 1px solid var(--border-color);
            border-radius: 12px;
            padding: 1.5rem;
            display: flex;
            flex-direction: column;
            box-shadow: var(--shadow);
            transition: all 0.3s ease;
            position: relative;
        }

        .tool-card:hover {
            box-shadow: var(--shadow-lg);
            transform: translateY(-3px);
        }

        /* Tool Icon - Top Left */
        .tool-icon {
            width: 48px;
            height: 48px;
            background: linear-gradient(135deg, var(--primary-color) 0%, #764ba2 100%);
            border-radius: 10px;
            display: flex;
            align-items: center;
            justify-content: center;
            margin-bottom: 1rem;
            color: white;
            flex-shrink: 0;
        }

        .tool-icon svg {
            width: 28px;
            height: 28px;
        }

        .tool-card h3 {
            font-size: 1.125rem;
            font-weight: 600;
            margin-bottom: 0.5rem;
            color: var(--text-primary);
        }

        .tool-card p {
            font-size: 0.875rem;
            color: var(--text-secondary);
            line-height: 1.6;
            flex: 1;
        }

        /* Launch Button - Bottom Right */
        .launch-btn {
            display: inline-flex;
            align-items: center;
            gap: 0.5rem;
            color: var(--primary-color);
            font-weight: 600;
            font-size: 0.875rem;
            text-decoration: none;
            align-self: flex-end;
            padding: 0.5rem 1rem;
            border-radius: 6px;
            transition: all 0.3s ease;
            margin-top: 1rem;
        }

        .launch-btn:hover {
            background: var(--primary-color);
            color: white;
        }

        .launch-btn svg {
            width: 16px;
            height: 16px;
        }

        /* Ad Card */
        .tool-card.ad-card {
            border: 2px dashed var(--border-color);
            justify-content: center;
            align-items: center;
            text-align: center;
        }

        .ad-label {
            position: absolute;
            top: 0.5rem;
            right: 0.5rem;
            background: var(--border-color);
            color: var(--text-secondary);
            padding: 0.25rem 0.75rem;
            border-radius: 4px;
            font-size: 0.7rem;
            font-weight: 500;
            text-transform: uppercase;
            letter-spacing: 0.5px;
        }

        .ad-content {
            margin-bottom: 1rem;
        }

        .ad-placeholder {
            background: var(--hover-bg);
            border: 2px dashed var(--border-color);
            border-radius: 8px;
            padding: 1.5rem;
            text-align: center;
            color: var(--text-secondary);
        }

        .ad-placeholder svg {
            margin-bottom: 0.5rem;
            opacity: 0.3;
        }

        .ad-placeholder p {
            margin: 0.25rem 0;
            font-weight: 600;
            opacity: 0.7;
            font-size: 0.75rem;
        }

        .ad-placeholder p:first-of-type {
            font-size: 1rem;
            color: var(--primary-color);
        }

        .ad-description {
            color: var(--text-secondary);
            font-size: 0.75rem;
            font-style: italic;
        }

        /* Features Section */
        .features-section {
            background: var(--hover-bg);
            padding: 4rem 1rem;
            border-top: 1px solid var(--border-color);
        }

        .features-section h2 {
            text-align: center;
            font-size: 2rem;
            margin-bottom: 3rem;
            color: var(--text-primary);
        }

        .features-grid {
            max-width: 1000px;
            margin: 0 auto;
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 2rem;
        }

        .feature {
            text-align: center;
        }

        .feature svg {
            color: var(--primary-color);
            margin-bottom: 1rem;
        }

        .feature h3 {
            font-size: 1.125rem;
            margin-bottom: 0.5rem;
            color: var(--text-primary);
        }

        .feature p {
            color: var(--text-secondary);
            font-size: 0.875rem;
        }

        /* Footer */
        .site-footer {
            background: var(--card-bg);
            border-top: 1px solid var(--border-color);
            padding: 2rem 1rem;
            text-align: center;
            margin-top: auto;
        }

        .footer-content p {
            color: var(--text-secondary);
            font-size: 0.875rem;
            margin-bottom: 0.5rem;
        }

        /* Responsive Design */
        @media (max-width: 1200px) {
            .tools-grid {
                grid-template-columns: repeat(3, 250px);
            }
        }

        @media (max-width: 900px) {
            .tools-grid {
                grid-template-columns: repeat(2, 250px);
            }
        }

        @media (max-width: 768px) {
            .hero-content h1 {
                font-size: 2rem;
            }

            .tools-grid {
                grid-template-columns: 250px;
            }
        }

        @media (max-width: 600px) {
            .hero-content h1 {
                font-size: 1.5rem;
            }

            .hero-content p {
                font-size: 1rem;
            }
        }