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

        :root {
            --bg-color: #ffffff;
            --text-color: #333333;
            --card-bg: #f8f9fa;
            --border-color: #e9ecef;
            --accent-color: #6366f1;
            --accent-hover: #5855eb;
            --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
            --shadow-hover: 0 10px 25px -3px rgba(0, 0, 0, 0.1);
        }

        [data-theme="dark"] {
            --bg-color: #1a1a1a;
            --text-color: #e5e7eb;
            --card-bg: #2d2d2d;
            --border-color: #404040;
            --accent-color: #818cf8;
            --accent-hover: #a78bfa;
            --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
            --shadow-hover: 0 10px 25px -3px rgba(0, 0, 0, 0.3);
        }

        body {
            font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
            background-color: var(--bg-color);
            color: var(--text-color);
            line-height: 1.6;
            transition: all 0.3s ease;
        }

        .container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 20px;
        }

        /* Header */
        .header {
            background: var(--bg-color);
            border-bottom: 1px solid var(--border-color);
            position: sticky;
            top: 0;
            z-index: 100;
            backdrop-filter: blur(10px);
        }

        .nav {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 1rem 0;
        }

        .logo {
            font-size: 1.5rem;
            font-weight: 700;
            color: var(--accent-color);
            text-decoration: none;
            cursor: pointer;
        }

        .theme-toggle {
            background: var(--card-bg);
            border: 1px solid var(--border-color);
            border-radius: 8px;
            padding: 0.5rem;
            cursor: pointer;
            transition: all 0.3s ease;
            font-size: 1.2rem;
        }

        .theme-toggle:hover {
            background: var(--accent-color);
            color: white;
        }

        /* Main Content */
        .main {
            padding: 2rem 0;
            min-height: 80vh;
        }

        .hero {
            text-align: center;
            margin-bottom: 3rem;
        }

        .hero h1 {
            font-size: 3rem;
            font-weight: 800;
            margin-bottom: 1rem;
            background: linear-gradient(135deg, var(--accent-color), var(--accent-hover));
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
        }

        .hero p {
            font-size: 1.25rem;
            color: var(--text-color);
            opacity: 0.8;
            max-width: 600px;
            margin: 0 auto;
        }

        /* Navigation Buttons */
        .nav-buttons {
            display: flex;
            justify-content: center;
            gap: 1rem;
            margin: 2rem 0;
            flex-wrap: wrap;
        }

        .nav-btn {
            background: var(--card-bg);
            border: 2px solid var(--border-color);
            border-radius: 12px;
            padding: 0.75rem 1.5rem;
            cursor: pointer;
            transition: all 0.3s ease;
            font-weight: 600;
            color: var(--text-color);
        }

        .nav-btn:hover,
        .nav-btn.active {
            background: var(--accent-color);
            color: white;
            border-color: var(--accent-color);
            transform: translateY(-2px);
            box-shadow: var(--shadow-hover);
        }

        /* Tool Cards */
        .tools-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
            gap: 2rem;
            margin: 2rem 0;
        }

        .tool-card {
            background: var(--card-bg);
            border: 1px solid var(--border-color);
            border-radius: 16px;
            padding: 1.5rem;
            transition: all 0.3s ease;
            box-shadow: var(--shadow);
        }

        .tool-card:hover {
            transform: translateY(-4px);
            box-shadow: var(--shadow-hover);
            border-color: var(--accent-color);
        }

        .tool-header {
            display: flex;flex-direction: column;
            justify-content: space-between;
            align-items: flex-start;
            margin-bottom: 1rem;
        }

        .tool-name {
            font-size: 1.25rem;
            font-weight: 700;
            color: var(--accent-color);
            margin-bottom: 0.5rem;
        }

        .tool-category {
            /*background: var(--accent-color);
            color: white;
            padding: 0.25rem 0.75rem;
            border-radius: 20px;*/
            font-size: 0.85rem;
            font-weight: 600;
        }

        .tool-description {
            margin: 1rem 0;
            opacity: 0.9;
            line-height: 1.6;
        }

        .tool-link {
            display: inline-block;
            background: var(--accent-color);
            color: white;
            padding: 0.75rem 1.5rem;
            border-radius: 8px;
            text-decoration: none;
            font-weight: 600;
            transition: all 0.3s ease;
            margin-top: 1rem;
        }

        .tool-link:hover {
            background: var(--accent-hover);
            transform: translateY(-1px);
        }

        /* Categories Grid */
        .categories-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
            gap: 1.5rem;
            margin: 2rem 0;
        }

        .category-card {
            background: var(--card-bg);
            border: 1px solid var(--border-color);
            border-radius: 12px;
            padding: 1.5rem;
            cursor: pointer;
            transition: all 0.3s ease;
            text-align: center;
        }

        .category-card:hover {
            transform: translateY(-2px);
            box-shadow: var(--shadow-hover);
            border-color: var(--accent-color);
        }

        .category-icon {
            font-size: 2.5rem;
            margin-bottom: 1rem;
        }

        .category-name {
            font-size: 1.25rem;
            font-weight: 700;
            margin-bottom: 0.5rem;
        }

        .category-count {
            color: var(--accent-color);
            font-weight: 600;
        }

        /* Footer */
        .footer {
            background: var(--card-bg);
            border-top: 1px solid var(--border-color);
            padding: 2rem 0;
            text-align: center;
            margin-top: 4rem;
        }

        /* Hidden class */
        .hidden {
            display: none;
        }

        /* Responsive */
        @media (max-width: 768px) {
            .hero h1 {
                font-size: 2rem;
            }
            
            .tools-grid {
                grid-template-columns: repeat(2, 1fr);
                gap: 1rem;
            }
            
            .tool-card {
                padding: 1rem;
            }
            
            .tool-name {
                font-size: 1rem;
            }
            
            .tool-description {
                font-size: 0.9rem;
            }
            
            .nav-buttons {
                flex-direction: column;
                align-items: center;
            }
            
            .nav-btn {
                width: 200px;
            }
            
            .categories-grid {
                grid-template-columns: repeat(2, 1fr);
                gap: 1rem;
            }
            
            .category-card {
                padding: 1rem;
            }
        }

        /* For very small screens */
        @media (max-width: 480px) {
            .container {
                padding: 0 10px;
            }
            
            .tools-grid {
                gap: 0.75rem;
            }
            
            .tool-card {
                padding: 0.75rem;
            }
            
            .categories-grid {
                gap: 0.75rem;
            }
        }