* {
				box-sizing: border-box;
				margin: 0;
				padding: 0;
				font-family: "PingFang SC", "Helvetica Neue", Arial, sans-serif;
			}

			body {
				background-color: #f5f5f5;
				color: #333;
				line-height: 1.6;
				max-width: 100%;
				overflow-x: hidden;
			}

			.container {
				max-width: 800px;
				margin: 0 auto;
			}

			.header {
				margin-bottom: 15px;
				padding-bottom: 10px;
				border-bottom: 1px solid #eee;
				text-align: center;
			}

			.difficulty-selector {
				display: flex;
				justify-content: space-between;
				margin-bottom: 15px;
				gap: 5px;
			}

			.difficulty-btn {
				flex: 1;
				padding: 8px 0;
				border: 2px solid;
				border-radius: 5px;
				font-weight: bold;
				background-color: #f8f8f8;
				cursor: pointer;
				transition: all 0.3s;
				font-size: 14px;
			}

			#easy-btn {
				color: #5FB878;
				border-color: #5FB878;
			}

			#medium-btn {
				color: #1E9FFF;
				border-color: #1E9FFF;
			}

			#hard-btn {
				color: #FF5722;
				border-color: #FF5722;
			}

			#easy-btn.active {
				background-color: #5FB878;
				color: white;
			}

			#medium-btn.active {
				background-color: #1E9FFF;
				color: white;
			}

			#hard-btn.active {
				background-color: #FF5722;
				color: white;
			}

			.sudoku-container {
				width: 100%;
				margin: 0 auto;
				background: #f6f7fa;
				padding: 15px;
				border-radius: 6px;
			}

			.sudoku-grid {
				display: grid;
				grid-template-columns: repeat(9, 1fr);
				gap: 1px;
				background: #333;
				border: 2px solid #333;
			}

			.sudoku-cell {
				aspect-ratio: 1;
				display: flex;
				align-items: center;
				justify-content: center;
				background: white;
				font-size: 20px;
				font-weight: bold;
				position: relative;
			}

			.sudoku-cell.fixed {
				background: #f0f0f0;
				color: #000;
			}

			.sudoku-cell:nth-child(3n) {
				border-right: 2px solid #333;
			}

			.sudoku-cell:nth-child(9n) {
				border-right: none;
			}

			.sudoku-cell:nth-child(n+19):nth-child(-n+27),
			.sudoku-cell:nth-child(n+46):nth-child(-n+54) {
				border-bottom: 2px solid #333;
			}

			.download-btn {
				display: block;
				width: 100%;
				background-color: #1E9FFF;
				color: white;
				border: none;
				border-radius: 5px;
				font-weight: bold;
				cursor: pointer;
				margin-top: 10px;
				text-align: center;
				transition: background-color 0.3s;
			}

			.download-btn:disabled {
				background-color: #cccccc;
				cursor: not-allowed;
			}

			.instructions {
				margin-top: 20px;
				padding: 15px;
				background-color: #f8f8f8;
				border-radius: 5px;
				font-size: 14px;
			}

			.instructions .title {
				font-weight: bold;
				display: block;
				margin-bottom: 5px;
			}

			.instructions text {
				display: block;
				margin-bottom: 3px;
			}

			.title {
				color: #333;
				font-size: 18px;
				text-decoration: none;
				text-align: center;
				display: block;
				margin-bottom: 15px;
			}

			@media (max-width: 400px) {
				.sudoku-cell {
					font-size: 16px;
				}

				.difficulty-btn {
					font-size: 12px;
					padding: 6px 0;
				}
			}

			/* Loading spinner */
			.spinner {
				display: none;
				width: 40px;
				height: 40px;
				margin: 10px auto;
				border: 4px solid #f3f3f3;
				border-top: 4px solid #1E9FFF;
				border-radius: 50%;
				animation: spin 1s linear infinite;
			}

			@keyframes spin {
				0% {
					transform: rotate(0deg);
				}

				100% {
					transform: rotate(360deg);
				}
			}

			/* Toast notification */
			.toast {
				position: fixed;
				bottom: 20px;
				left: 50%;
				transform: translateX(-50%);
				background-color: #333;
				color: white;
				padding: 12px 24px;
				border-radius: 4px;
				box-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
				z-index: 1000;
				opacity: 0;
				transition: opacity 0.3s;
			}

			.toast.show {
				opacity: 1;
			}


			#myList li {
				width: 50%;
				float: left;
			}