:root {
            --primary: #6366f1;
            --success: #22c55e; 
            --danger-light: #fee2e2; 
            --bg: #f3f4f6;
            --card: #ffffff;
            --text: #1f2937;
        }

        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            background-color: var(--bg);
            color: var(--text);
            display: flex;
            justify-content: center;
            padding: 20px;
            margin: 0;
        }

        .container {
            width: 100%;
            max-width: 500px;
            background: var(--card);
            padding: 2rem;
            border-radius: 12px;
            box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
        }

        h1 { text-align: center; margin-bottom: 1.5rem; color: var(--primary); }

        .input-group {
            display: flex;
            gap: 10px;
            margin-bottom: 20px;
        }

        input[type="text"] {
            flex: 1;
            padding: 10px;
            border: 1px solid #d1d5db;
            border-radius: 6px;
            outline: none;
        }

        button#addBtn {
            background: var(--primary);
            color: white;
            border: none;
            padding: 10px 20px;
            border-radius: 6px;
            cursor: pointer;
            font-weight: bold;
        }

        button#addBtn:hover { background: #4f46e5; }

        .filters {
            display: flex;
            justify-content: center;
            gap: 10px;
            margin-bottom: 20px;
            padding-bottom: 15px;
            border-bottom: 1px solid #e5e7eb;
        }

        .filter-btn {
            background: none;
            border: 1px solid #d1d5db;
            padding: 5px 10px;
            border-radius: 15px;
            cursor: pointer;
            font-size: 0.9rem;
            transition: all 0.2s;
        }

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

        ul { list-style: none; padding: 0; }

        li {
            background: #f9fafb;
            border: 1px solid #e5e7eb;
            margin-bottom: 8px;
            padding: 10px;
            border-radius: 6px;
            display: flex;
            align-items: center;
            justify-content: space-between;
            transition: all 0.3s ease;
        }

        
        li.completed {
            background: var(--success); 
            border-color: #10b981;
            color: #1f2937;
        }
        
        li.pending {
            background: var(--danger-light); 
            border-color: #fca5a5;
            color: var(--text);
        }

        li.completed .task-content {
            text-decoration: line-through;
            opacity: 0.8;
        }
        
        .checkbox-container {
            display: flex;
            align-items: center;
            gap: 10px;
            flex: 1;
        }
        
        .custom-checkbox {
            width: 20px;
            height: 20px;
            border: 2px solid;
            border-radius: 4px;
            display: flex;
            align-items: center;
            justify-content: center;
            cursor: pointer;
            transition: all 0.2s;
        }
        
        .task-content-text {
            cursor: pointer;
            padding-right: 5px;
            flex: 1;
        }
        
     
        li.completed .custom-checkbox {
            background-color: white;
            border-color: white;
        }
        li.completed .custom-checkbox::after {
            content: '✓';
            color: var(--success);
            font-size: 14px;
        }

        li.pending .custom-checkbox {
            border-color: #ef4444;
        }
        li.pending .custom-checkbox::after {
            content: ''; 
        }


        .delete-btn {
            background: transparent;
            color: var(--danger);
            border: none;
            cursor: pointer;
            font-size: 1.2rem;
            padding: 0 5px;
        }

        .delete-btn:hover { color: #dc2626; }

        .empty-state {
            text-align: center;
            color: #9ca3af;
            margin-top: 20px;
        }