Yes, it is possible to customize the default hamburger menu icon in the navbar widget on Webflow. Here's how you can do it:
1. Select the navbar element in the Webflow Designer by clicking on it.
2. In the right-hand sidebar, you will see the navbar settings panel. Click on the "Open menu" section.
3. Scroll down to the "Hamburger icon" option. By default, it is set to "Default." Click on the drop-down menu next to it.
4. You will see several options available to choose from. The "Custom" option allows you to upload your own custom hamburger menu icon.
5. To use your own custom hamburger menu icon, click on the "Custom" option and then click on the "Choose image" button. Upload the image you want to use as your hamburger menu icon.
6. Once you have uploaded the custom image, you can further customize its appearance by adjusting the padding, size, and color options available in the settings panel.
7. You can also set different styles for the hamburger menu icon in its regular state and hover state by using the "Normal" and "Hover" tabs in the settings panel.
8. After you have customized the hamburger menu icon to your liking, you can preview the changes in the Webflow Designer or publish the site to see the changes in the live site.
Remember to optimize your custom hamburger menu icon for different screen sizes and make sure it looks good on all devices. Also, keep in mind that altering the default icon may affect the user experience, so ensure that your custom icon is intuitive and easily recognizable as a menu icon.