Widget Styler 1.0 Download Allows widget styling from the front end.

This module enables basic styling for widgets from the front end portal. You must have control wrappers feature enabled so that an option will be displayed for styling per widget. By default the feature is enabled for html widget content type but you can use it for other widgets by attaching the appropriate content part to your widget. For some style settings (like border radius and shadow) the module uses css3 style rules, so only moderns browsers will support these settings. Will investigate in future version to support older browsers. Also note that styling depends on the inner html within a widget. There may be cases where your widgets inner html may override the custom styling being applied by this module.