:root{--primary-color: #3498db;--secondary-color: #2ecc71;--danger-color: #e74c3c;--background-color: #f8f9fa;--text-color: #333;--border-color: #ddd}*{box-sizing:border-box;margin:0;padding:0}body{font-family:Segoe UI,Tahoma,Geneva,Verdana,sans-serif;background-color:var(--background-color);color:var(--text-color);line-height:1.6}.container{max-width:800px;margin:0 auto;padding:20px}.todo-list{background-color:#fff;border-radius:8px;box-shadow:0 2px 10px #0000001a;padding:20px;margin-top:40px}.todo-list h1{text-align:center;margin-bottom:20px;color:var(--primary-color)}.add-todo-form{display:flex;margin-bottom:20px}.add-todo-form input{flex:1;padding:10px;border:1px solid var(--border-color);border-radius:4px 0 0 4px;font-size:16px}.add-todo-form button{padding:10px 20px;background-color:var(--primary-color);color:#fff;border:none;border-radius:0 4px 4px 0;cursor:pointer;font-size:16px;transition:background-color .2s}.add-todo-form button:hover{background-color:#2980b9}.todo-item{display:flex;justify-content:space-between;align-items:center;padding:15px;border-bottom:1px solid var(--border-color)}.todo-item:last-child{border-bottom:none}.todo-content{display:flex;align-items:center;gap:10px}.todo-content input[type=checkbox]{width:20px;height:20px}.todo-content input[type=text]{padding:5px;border:1px solid var(--border-color);border-radius:4px;font-size:16px}.todo-content span{font-size:16px}.todo-content span.done{text-decoration:line-through;color:#999}.todo-actions{display:flex;gap:5px}.todo-actions button{padding:5px 10px;background-color:var(--primary-color);color:#fff;border:none;border-radius:4px;cursor:pointer;transition:background-color .2s}.todo-actions button:hover{background-color:#2980b9}.todo-actions button:last-child{background-color:var(--danger-color)}.todo-actions button:last-child:hover{background-color:#c0392b}