unify panel color and fix concerns

apps/remix-ide/src/app.js

@@ -90,7 +90,6 @@ const css = csjs`
     display            : flex;
     flex-direction     : row-reverse;
     width              : 320px;
-    margin-right       : -1px;
   }
   .highlightcode       {
     position           : absolute;

apps/remix-ide/src/assets/css/themes/remix-hacker_owl.css

@@ -8722,7 +8722,7 @@ a.text-dark:hover {
 
 /* Plugins manager */
 .plugin-manager {
-  background: var(--theme-background-panels);
+  background: var(--light);
 }
 .plugins-header {
   background-color: var(--theme-background-panels) !important;
@@ -8909,3 +8909,7 @@ remix-tab .fak {
 .ace_rightAlignedText {
   color: var(--theme-ace-symbols)!important;
 }
+
+div[data-id="remixIdeSidePanel"] {
+  margin-right: -1px
+}