Index: src/wp-includes/widgets.php
===================================================================
--- src/wp-includes/widgets.php	(revision 53262)
+++ src/wp-includes/widgets.php	(working copy)
@@ -1606,7 +1606,18 @@
 		return;
 	}
 
-	echo '<ul>';
+	$rss_classes = 'rss-widget-list';
+	if ( $show_summary ) {
+		$rss_classes .= ' rss-widget-show-summary';
+	}
+	if ( $show_author ) {
+		$rss_classes .= ' rss-widget-show-author';
+	}
+	if ( $show_date ) {
+		$rss_classes .= ' rss-widget-show-date';
+	}
+
+	echo '<ul class="' . $rss_classes . '">';
 	foreach ( $rss->get_items( 0, $items ) as $item ) {
 		$link = $item->get_link();
 		while ( ! empty( $link ) && stristr( $link, 'http' ) !== $link ) {
@@ -1622,6 +1633,8 @@
 		$desc = html_entity_decode( $item->get_description(), ENT_QUOTES, get_option( 'blog_charset' ) );
 		$desc = esc_attr( wp_trim_words( $desc, 55, ' [&hellip;]' ) );
 
+		$item_classes = 'rss-widget-item';
+
 		$summary = '';
 		if ( $show_summary ) {
 			$summary = $desc;
@@ -1632,6 +1645,8 @@
 			}
 
 			$summary = '<div class="rssSummary">' . esc_html( $summary ) . '</div>';
+
+			$item_classes .= ' rss-widget-has-summary';
 		}
 
 		$date = '';
@@ -1641,6 +1656,8 @@
 			if ( $date ) {
 				$date = ' <span class="rss-date">' . date_i18n( get_option( 'date_format' ), $date ) . '</span>';
 			}
+
+			$item_classes .= ' rss-widget-has-date';
 		}
 
 		$author = '';
@@ -1649,15 +1666,18 @@
 			if ( is_object( $author ) ) {
 				$author = $author->get_name();
 				$author = ' <cite>' . esc_html( strip_tags( $author ) ) . '</cite>';
+
+				$item_classes .= ' rss-widget-has-author';
 			}
 		}
 
 		if ( '' === $link ) {
-			echo "<li>$title{$date}{$summary}{$author}</li>";
+			$item_classes .= ' rss-widget-has-no-link';
+			echo "<li class='$item_classes'>$title{$date}{$summary}{$author}</li>";
 		} elseif ( $show_summary ) {
-			echo "<li><a class='rsswidget' href='$link'>$title</a>{$date}{$summary}{$author}</li>";
+			echo "<li class='$item_classes'><a class='rsswidget' href='$link'>$title</a>{$date}{$summary}{$author}</li>";
 		} else {
-			echo "<li><a class='rsswidget' href='$link'>$title</a>{$date}{$author}</li>";
+			echo "<li class='$item_classes'><a class='rsswidget' href='$link'>$title</a>{$date}{$author}</li>";
 		}
 	}
 	echo '</ul>';