Merge pull request #227 from ckeditor/t/ckeditor5-ui/491

Feature: Introduced rotatable panels styles for `ContextualBalloon`.

theme/ckeditor5-ui/components/panel/balloonrotator.css

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+ * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license
+ */
+
+.ck .ck-balloon-rotator__navigation {
+	background: var(--ck-color-toolbar-background);
+	border-bottom: 1px solid var(--ck-color-toolbar-border);
+	padding: 0 var(--ck-spacing-small);
+
+	/* Let's keep similar appearance to `ck-toolbar`. */
+	& > * {
+		margin-right: var(--ck-spacing-small);
+		margin-top: var(--ck-spacing-small);
+		margin-bottom: var(--ck-spacing-small);
+	}
+
+	/* Gives counter more breath than buttons. */
+	& .ck-balloon-rotator__counter {
+		margin-right: var(--ck-spacing-standard);
+		margin-left: var(--ck-spacing-standard);
+	}
+}