diff --git a/components/PoweredBy.js b/components/PoweredBy.js
index e07825ea..87b8705f 100644
--- a/components/PoweredBy.js
+++ b/components/PoweredBy.js
@@ -7,7 +7,7 @@ import { siteConfig } from '@/lib/config'
 export default function PoweredBy(props) {
   return (
     <div
-      className={`gap-x-1 flex flex-wrap text-sm font-serif ${props.className}`}>
+      className={`gap-x-1 flex flex-wrap text-sm font-serif ${props.className || ''}`}>
       <span>Powered by</span>
       <a
         href='https://github.com/tangly1024/NotionNext'
diff --git a/themes/hexo/components/Footer.js b/themes/hexo/components/Footer.js
index af16bb5d..2f3a1434 100644
--- a/themes/hexo/components/Footer.js
+++ b/themes/hexo/components/Footer.js
@@ -35,7 +35,7 @@ const Footer = ({ title }) => {
         <h1 className='text-xs pt-4 text-light-400 dark:text-gray-400'>
           {title} {siteConfig('BIO') && <>|</>} {siteConfig('BIO')}
         </h1>
-        <PoweredBy />
+        <PoweredBy className='justify-center' />
       </span>
       <br />
     </footer>