:root {
            --primary: hsl(258, 60%, 50%);
            --primary-light: hsl(258, 60%, 60%);
            --secondary: hsl(203, 89%, 53%);
            --text: hsl(260, 20%, 30%);
            --bg: hsl(258, 50%, 98%);
            --card-bg: hsl(0, 0%, 100%);
        }

        body {
            font-family: 'Inter', sans-serif;
            background-color: var(--bg);
            color: var(--text);
            min-height: 100vh;
            padding: 2rem;
        }

        .todo-card {
            background: var(--card-bg);
            border-radius: 0.75rem;
            box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
            transition: all 0.2s ease;
            opacity: 0;
            transform: translateY(20px);
            animation: fadeIn 0.3s forwards;
        }

        .todo-card:hover {
            transform: translateY(-2px);
            box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
        }

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

        .checkbox {
            appearance: none;
            width: 1.5rem;
            height: 1.5rem;
            border: 2px solid var(--primary);
            border-radius: 0.25rem;
            cursor: pointer;
            transition: all 0.2s ease;
            display: flex;
            align-items: center;
            justify-content: center;
        }

        .checkbox:checked {
            background-color: var(--primary);
        }

        .checkbox:checked::after {
            content: "✓";
            color: white;
            font-size: 0.875rem;
        }

        .add-btn {
            background: linear-gradient(135deg, var(--primary), var(--secondary));
            transition: all 0.2s ease;
        }

        .add-btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.2);
        }

        .filter-btn.active {
            background-color: var(--primary-light);
            color: white;
        }

        .completed {
            opacity: 0.7;
            text-decoration: line-through;
        }