If you want to change the styling of the Back-to-Top button. do this:
In case you feel more comfortable with written instructions, please follow the steps below:
1. Download and edit the image used for the button and its hover state.
Remember, the bottom half of the image is used for the Hover effect.
2. Upload your edited image using the Media Manager, and copy the image URL.
3. Go to Theme Settings > Advanced > Custom Style Options (Custom CSS) and paste
the following code, replacing the URL placeholder with the edited image’s URL
you copied in step #2.
background: url(YOUR_IMAGE_URL_HERE) no-repeat left top;
background: url(YOUR_IMAGE_URL_HERE) no-repeat left -51px;
4. Click Save Changes and you’re ready!