:root {
            --primary: #3b82f6;
            --secondary: #10b981;
            --accent: #f59e0b;
            --dark: #1f2937;
            --light: #f9fafb;
        }

        * {
            transition: all 0.3s ease;
        }

        .gradient-bg {
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
        }

        .bookmark-card {
            transition: all 0.3s ease;
            border-left: 4px solid transparent;
            contain: content; /* Optimize rendering performance */
            animation: fadeIn 0.5s ease-in;
        }

        .bookmark-card:hover {
            transform: translateY(-2px);
            box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.1);
            border-left-color: var(--primary);
        }

        .favicon-placeholder {
            width: clamp(32px, 8vw, 36px);
            height: clamp(32px, 8vw, 36px);
            border-radius: 8px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: bold;
            color: white;
        }

        .category-badge {
            display: inline-flex;
            align-items: center;
            padding: 0.25rem 0.75rem;
            border-radius: 1rem;
            font-size: clamp(0.65rem, 2vw, 0.75rem);
            font-weight: 500;
        }

        .tag {
            display: inline-flex;
            align-items: center;
            background: #e5e7eb;
            padding: 0.2rem 0.6rem;
            border-radius: 0.75rem;
            font-size: clamp(0.6rem, 1.8vw, 0.7rem);
            margin-right: 0.4rem;
            margin-bottom: 0.4rem;
            cursor: pointer;
        }

        .modal {
            transition: all 0.3s ease;
            opacity: 0;
            visibility: hidden;
            overflow-y: auto;
        }

        .modal.active {
            opacity: 1;
            visibility: visible;
        }

        .modal > div {
            max-height: 90vh;
            overflow-y: auto;
        }

        .toast {
            position: fixed;
            padding: clamp(0.75rem, 2vw, 1rem) clamp(1rem, 2.5vw, 1.5rem);
            border-radius: 0.5rem;
            color: white;
            z-index: 1000;
            transform: translateY(100%);
            transition: transform 0.3s ease;
        }

        .toast.show {
            transform: translateY(0);
        }

        .toast.success {
            background: #10b981;
        }

        .toast.error {
            background: #ef4444;
        }

        .toast.info {
            background: #3b82f6;
        }

        .dark-mode {
            background-color: #1a202c;
            color: #e2e8f0;
        }

        .dark-mode .bg-white {
            background-color: #2d3748;
        }

        .dark-mode .bg-gray-50 {
            background-color: #2d3748;
        }

        .dark-mode .bg-gray-100 {
            background-color: #4a5568;
        }

        .dark-mode .text-gray-800 {
            color: #e2e8f0;
        }

        .dark-mode .text-gray-600 {
            color: #a0aec0;
        }

        .dark-mode .text-gray-700 {
            color: #e2e8f0;
        }

        .dark-mode .border {
            border-color: #4a5568;
        }

        .dark-mode input,
        .dark-mode textarea,
        .dark-mode select {
            background-color: #2d3748;
            color: #e2e8f0;
            border-color: #4a5568;
        }

        .dark-mode .tag {
            background-color: #4a5568;
            color: #e2e8f0;
        }

        .dark-mode .shadow-sm {
            box-shadow: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
        }

        .skeleton {
            background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
            background-size: 200% 100%;
            animation: loading 1.5s infinite;
        }

        .dark-mode .skeleton {
            background: linear-gradient(90deg, #2d3748 25%, #4a5568 50%, #2d3748 75%);
            background-size: 200% 100%;
            animation: loading 1.5s infinite;
        }

        @keyframes loading {
            0% { background-position: 200% 0; }
            100% { background-position: -200% 0; }
        }

        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(10px); }
            to { opacity: 1; transform: translateY(0); }
        }

        .grid-layout {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(clamp(250px, 30vw, 280px), 1fr));
            gap: clamp(1rem, 2vw, 1.5rem);
        }

        /* Footer Styles */
        footer {
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            padding: clamp(1rem, 2vw, 1.5rem);
            text-align: center;
        }

        footer .container {
            max-width: 1280px;
            margin: 0 auto;
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: 0.5rem;
        }

        footer p {
            font-size: clamp(0.8rem, 1.8vw, 0.9rem);
            display: flex;
            align-items: center;
            gap: 0.5rem;
        }

        footer .fa-code {
            font-size: clamp(1rem, 2vw, 1.2rem);
        }

        .dark-mode footer {
            background: linear-gradient(135deg, #4b5e9e 0%, #5a3e7a 100%);
        }

        /* Responsive Adjustments */
        @media (max-width: 640px) {
            .grid-layout {
                grid-template-columns: 1fr;
                gap: 1rem;
            }

            .modal {
                padding: 0.5rem;
            }

            .modal > div {
                max-width: 95%;
                padding: 1rem;
            }

            .bookmark-card {
                padding: 1rem;
            }

            .bookmark-card h3 {
                font-size: clamp(0.9rem, 3vw, 1rem);
            }

            .category-badge, .tag {
                font-size: clamp(0.6rem, 2vw, 0.65rem);
                padding: 0.2rem 0.6rem;
            }

            .toast {
                bottom: 10px;
                top: auto;
                right: 10px;
                left: 10px;
                padding: clamp(0.5rem, 2vw, 0.75rem) clamp(0.75rem, 2.5vw, 1rem);
                font-size: clamp(0.8rem, 2.2vw, 0.85rem);
            }

            header {
                padding: 1rem;
            }

            header h1 {
                font-size: clamp(1.5rem, 4vw, 1.8rem);
            }

            header p {
                font-size: clamp(0.8rem, 2vw, 0.9rem);
            }

            .stats-card {
                padding: 1rem;
            }

            .stats-card h3 {
                font-size: clamp(1.2rem, 3.5vw, 1.5rem);
            }

            .categories-grid {
                grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
                gap: 0.75rem;
            }
        }

        @media (min-width: 640px) and (max-width: 1024px) {
            .grid-layout {
                grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
                gap: 1.25rem;
            }

            .bookmark-card {
                padding: 1.25rem;
            }

            .modal > div {
                max-width: 85%;
            }

            .categories-grid {
                grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
            }
        }

        @media (min-width: 1024px) {
            .categories-grid {
                grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
            }
        }