need simple CSS help

I am having trouble styling a widget. It seems like it should be pretty simple but I am not a programmer. Hoping someone can offer some guidance.

This is what I want it to look like.

This is what it currently looks like. (scroll down to middle of right column)

Basically, I want the selected (active) content to share the background color with the hover and selected (active) tab. The whole things should sit on a background with a darker green color and rounded corners, which I want to create with a bottom image and top image.

Do I need to create new classes, and if so how/where do I put them? I tried a few different approaches but could not get it to work. Any help greatly appreciated.

I think this is the bit of code in the php file that is related:

$params[0]['before_widget'] = '<div id="tw-content-'. $widget_no .'-'. $id .'" class="tw-content">';
				$params[0]['before_title'] = '<span style="display:none;">';
				$params[0]['after_title'] =  '</span><h4 id="tw-title-'. $widget_no .'-'. $id .'" class="tw-title">' . $widget_title. '</h4>';
				$params[0]['after_widget'] = '</div>';

Here are the related classes in the plugin’s CSS:

/* General */

.tw-content { display:block; float:left; margin-left:12px; width:95%; background-color:#b7d869; }
.tabbed-widget { float:left; width:100%; border:none; } 

/* Tabbed  */

.tabbed-widget .ui-tabs-hide { display:none; }

.tabbed-widget .ui-state-active a { font-weight:bold; text-decoration:none; background: #fa8d88;
	color: #75ba3d;
	padding: 0px 8px 0px 8px;
	}
.tabbed-widget .ui-tabs .ui-tabs-nav { float:left; width:100%; clear:both; margin: 0px 0px 0px 3px; padding:0; }

.tabbed-widget .ui-tabs .ui-tabs-nav li { display:block; float:left; width:auto; }

.tabbed-widget .ui-tabs li.ui-tabs-selected a { background: #fa8d88;
	color: #75ba3d;
        font-weight: bold;
         text-decoration:none; }

.tabbed-widget .ui-tabs .ui-tabs-nav li a:hover {
	background: #fa8d88;
	color: #75ba3d;
        font-weight: bold;
	}

.tabbed-widget .ui-tabs .ui-tabs-nav li a {
	background: #75b93c;
	color: #c2e047;
	display: block;
	font-family: Arial, Tahoma, Verdana;
	font-size: 15px;
	font-weight: bold;
	padding: 3px 8px 3px 8px;
	text-decoration: none;
	}