Fix duplicate Tailwind class and JSX class attribute in themes.mdx

customize/themes.mdx

@@ -16,7 +16,7 @@
         <h4 className="text-base font-medium text-gray-900 dark:text-gray-200">{title}</h4>
         <label className="text-sm text-gray-500 dark:text-gray-400">"{value}"</label>
       </div>
-        <div class="mt-1 prose-sm prose-gray mb-2 text-gray-500 dark:text-gray-400">{description}</div>
+        <div className="mt-1 prose-sm prose-gray mb-2 text-gray-500 dark:text-gray-400">{description}</div>
         <div className="flex items-center gap-1 mt-2 text-green-600 group-hover:text-green-800 dark:text-green-500 dark:group-hover:text-green-400">
           <span className="text-sm font-medium">
             See preview
@@ -27,13 +27,13 @@
         </div>
       </div>
     </a>
   );
 };
 
-<div className="pt-10 pb-24 px-4 px-4 max-w-3xl mx-auto prose prose-gray">
+<div className="pt-10 pb-24 px-4 max-w-3xl mx-auto prose prose-gray">
   <label className="eyebrow h-5 text-primary dark:text-primary-light text-sm font-semibold">Core Concepts</label>
   <h1 className="mt-1 mb-2 text-2xl sm:text-3xl text-gray-900 tracking-tight dark:text-gray-200 font-semibold">Themes</h1>
   <label className="text-lg prose prose-gray dark:prose-invert">Customize the appearance of your documentation<br /><br />Configure [theme](/organize/settings-appearance#theme) in docs.json using one of the following themes.</label>
 
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