PanelContent: Refactored to accept className prop

src/meta/PanelContent.tsx

 import React from 'react';
+import classNames from "../util/classNames";
 
-const PanelContent = (props: {padding?: boolean, children: any}) => {
+const PanelContent = (props: {padding?: boolean, className?: string, children: any}) => {
   return (
-    <div className={"flex-1 " + ((props.padding ?? true) ? "px-5 pb-4" : "")}>
+    <div className={classNames(
+      "flex-1",
+      (props.padding ?? true) ? "px-5 pb-4" : "",
+      props.className
+    )}>
       {props.children}
     </div>
   );