Custom CSS
How to remove all of the existing styling for Simple Share Buttons Plus and use your own.
On the styling page for Simple Share Buttons Plus, click the CSS tab then click Additional.

To use the Custom CSS feature, it must first be enabled. Switch the switch to the ON position to do so.

Enter in any Custom CSS you may need/want to into the textarea. This option is perfect if you are confident with CSS and want to style your share buttons entirely your own way.

Note that when enabled, CSS added into this field will completely override the share button styles applied by the plugin itself. If you wish to simply add some additional CSS see the Additional CSS option.