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

        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            min-height: 100vh;
            padding: 20px;
            transition: all 0.3s ease;
        }

        body.dark-mode {
            background: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
        }

        .container {
            max-width: 800px;
            margin: 0 auto;
            background: rgba(255, 255, 255, 0.95);
            backdrop-filter: blur(10px);
            border-radius: 20px;
            box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
            padding: 40px;
            transition: all 0.3s ease;
        }

        .dark-mode .container {
            background: rgba(30, 30, 46, 0.95);
            box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
        }

        .header {
            text-align: center;
            margin-bottom: 40px;
            position: relative;
        }

        .header h1 {
            color: #2c3e50;
            font-size: 2.5rem;
            font-weight: 700;
            margin-bottom: 10px;
            transition: all 0.3s ease;
        }

        .dark-mode .header h1 {
            color: #e0e6ed;
        }

        .header p {
            color: #7f8c8d;
            font-size: 1.1rem;
            transition: all 0.3s ease;
        }

        .dark-mode .header p {
            color: #a0a6b0;
        }

        .theme-toggle {
            position: absolute;
            top: 0;
            right: 0;
            width: 60px;
            height: 30px;
            background: #e0e6ed;
            border-radius: 15px;
            cursor: pointer;
            transition: all 0.3s ease;
            display: flex;
            align-items: center;
            padding: 3px;
        }

        .dark-mode .theme-toggle {
            background: #4a5568;
        }

        .theme-toggle::before {
            content: '☀️';
            font-size: 16px;
            transition: all 0.3s ease;
        }

        .dark-mode .theme-toggle::before {
            content: '🌙';
        }

        .theme-toggle::after {
            content: '';
            width: 24px;
            height: 24px;
            background: white;
            border-radius: 50%;
            position: absolute;
            transition: all 0.3s ease;
            box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
        }

        .dark-mode .theme-toggle::after {
            transform: translateX(30px);
            background: #2d3748;
        }

        .input-section {
            display: flex;
            gap: 15px;
            margin-bottom: 30px;
            flex-wrap: wrap;
        }

        .task-input {
            flex: 1;
            min-width: 250px;
            padding: 15px 20px;
            border: 2px solid #e0e6ed;
            border-radius: 12px;
            font-size: 16px;
            outline: none;
            transition: all 0.3s ease;
            background: white;
            color: #2c3e50;
        }

        .dark-mode .task-input {
            background: #2d3748;
            border-color: #4a5568;
            color: #e0e6ed;
        }

        .task-input:focus {
            border-color: #667eea;
            box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
        }

        .dark-mode .task-input:focus {
            border-color: #805ad5;
            box-shadow: 0 0 0 3px rgba(128, 90, 213, 0.2);
        }

        .priority-select {
            padding: 15px 20px;
            border: 2px solid #e0e6ed;
            border-radius: 12px;
            font-size: 16px;
            outline: none;
            cursor: pointer;
            background: white;
            transition: all 0.3s ease;
            color: #2c3e50;
        }

        .dark-mode .priority-select {
            background: #2d3748;
            border-color: #4a5568;
            color: #e0e6ed;
        }

        .priority-select:focus {
            border-color: #667eea;
            box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
        }

        .dark-mode .priority-select:focus {
            border-color: #805ad5;
            box-shadow: 0 0 0 3px rgba(128, 90, 213, 0.2);
        }

        .add-btn {
            padding: 15px 30px;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            border: none;
            border-radius: 12px;
            font-size: 16px;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s ease;
            box-shadow: 0 4px 15px rgba(102, 126, 234, 0.3);
        }

        .dark-mode .add-btn {
            background: linear-gradient(135deg, #805ad5 0%, #9f7aea 100%);
            box-shadow: 0 4px 15px rgba(128, 90, 213, 0.3);
        }

        .add-btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 6px 20px rgba(102, 126, 234, 0.4);
        }

        .dark-mode .add-btn:hover {
            box-shadow: 0 6px 20px rgba(128, 90, 213, 0.4);
        }

        .stats {
            display: flex;
            justify-content: space-around;
            margin-bottom: 30px;
            padding: 20px;
            background: rgba(102, 126, 234, 0.1);
            border-radius: 12px;
            transition: all 0.3s ease;
        }

        .dark-mode .stats {
            background: rgba(128, 90, 213, 0.2);
        }

        .stat-item {
            text-align: center;
        }

        .stat-number {
            font-size: 2rem;
            font-weight: 700;
            color: #667eea;
            transition: all 0.3s ease;
        }

        .dark-mode .stat-number {
            color: #805ad5;
        }

        .stat-label {
            color: #7f8c8d;
            font-size: 0.9rem;
            margin-top: 5px;
            transition: all 0.3s ease;
        }

        .dark-mode .stat-label {
            color: #a0a6b0;
        }

        .filters {
            display: flex;
            gap: 10px;
            margin-bottom: 20px;
            flex-wrap: wrap;
        }

        .filter-btn {
            padding: 8px 16px;
            border: 2px solid #e0e6ed;
            background: white;
            border-radius: 20px;
            cursor: pointer;
            transition: all 0.3s ease;
            font-size: 14px;
            color: #2c3e50;
        }

        .dark-mode .filter-btn {
            background: #2d3748;
            border-color: #4a5568;
            color: #e0e6ed;
        }

        .filter-btn.active {
            background: #667eea;
            color: white;
            border-color: #667eea;
        }

        .dark-mode .filter-btn.active {
            background: #805ad5;
            border-color: #805ad5;
        }

        .todo-list {
            max-height: 400px;
            overflow-y: auto;
            padding-right: 10px;
        }

        .todo-item {
            display: flex;
            align-items: center;
            gap: 15px;
            padding: 20px;
            margin-bottom: 15px;
            background: white;
            border-radius: 12px;
            border: 2px solid #f8f9fa;
            transition: all 0.3s ease;
            animation: slideIn 0.3s ease-out;
        }

        .dark-mode .todo-item {
            background: #2d3748;
            border-color: #4a5568;
        }

        .todo-item:hover {
            border-color: #667eea;
            transform: translateY(-2px);
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
        }

        .dark-mode .todo-item:hover {
            border-color: #805ad5;
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
        }

        .todo-item.completed {
            opacity: 0.7;
            background: #f8f9fa;
        }

        .dark-mode .todo-item.completed {
            background: #1a202c;
        }

        .todo-item.completed .todo-text {
            text-decoration: line-through;
            color: #7f8c8d;
        }

        .dark-mode .todo-item.completed .todo-text {
            color: #718096;
        }

        .todo-checkbox {
            width: 20px;
            height: 20px;
            border: 2px solid #ddd;
            border-radius: 50%;
            cursor: pointer;
            transition: all 0.3s ease;
            flex-shrink: 0;
        }

        .todo-checkbox.checked {
            background: #27ae60;
            border-color: #27ae60;
            position: relative;
        }

        .todo-checkbox.checked::after {
            content: '✓';
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            color: white;
            font-size: 12px;
            font-weight: bold;
        }

        .todo-text {
            flex: 1;
            font-size: 16px;
            color: #2c3e50;
            font-weight: 500;
            transition: all 0.3s ease;
        }

        .dark-mode .todo-text {
            color: #e0e6ed;
        }

        .priority-badge {
            padding: 4px 12px;
            border-radius: 20px;
            font-size: 12px;
            font-weight: 600;
            text-transform: uppercase;
            letter-spacing: 0.5px;
        }

        .priority-high {
            background: #e74c3c;
            color: white;
        }

        .priority-medium {
            background: #f39c12;
            color: white;
        }

        .priority-low {
            background: #27ae60;
            color: white;
        }

        .delete-btn {
            padding: 8px 12px;
            background: #e74c3c;
            color: white;
            border: none;
            border-radius: 8px;
            cursor: pointer;
            font-size: 12px;
            transition: all 0.3s ease;
            opacity: 0.7;
        }

        .delete-btn:hover {
            opacity: 1;
            transform: scale(1.05);
        }

        .empty-state {
            text-align: center;
            padding: 60px 20px;
            color: #7f8c8d;
            transition: all 0.3s ease;
        }

        .dark-mode .empty-state {
            color: #a0a6b0;
        }

        .empty-state img {
            width: 100px;
            height: 100px;
            margin-bottom: 20px;
            opacity: 0.5;
        }

        @keyframes slideIn {
            from {
                opacity: 0;
                transform: translateY(20px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        .todo-list::-webkit-scrollbar {
            width: 8px;
        }

        .todo-list::-webkit-scrollbar-track {
            background: #f1f1f1;
            border-radius: 10px;
        }

        .todo-list::-webkit-scrollbar-thumb {
            background: #667eea;
            border-radius: 10px;
        }

        .dark-mode .todo-list::-webkit-scrollbar-thumb {
            background: #805ad5;
        }

        .dark-mode .todo-list::-webkit-scrollbar-track {
            background: #2d3748;
        }

        @media (max-width: 768px) {
            .container {
                padding: 20px;
            }
            
            .input-section {
                flex-direction: column;
            }
            
            .task-input {
                min-width: 100%;
            }
            
            .stats {
                flex-direction: column;
                gap: 15px;
            }
        }