Adopt panel system for plugins

Change-Id: I54f520382fb4a26c05ccb2cf0cd3cb48737933ac
diff --git a/dev/scss/main/plugin.scss b/dev/scss/main/plugin.scss
index 6b2b715..d8c26a2 100644
--- a/dev/scss/main/plugin.scss
+++ b/dev/scss/main/plugin.scss
@@ -1,11 +1,10 @@
 @import "../util";
 
-div.widget {
-  margin-right: $right-match-distance;
-
+div.view.widget {
+  padding-right: $right-match-distance;
   > iframe {
-    box-sizing: border-box;
     margin: 0;
+    box-sizing: border-box;
     padding: 0;
     width: 100%;
     overflow-x: auto;