diff --git a/astro.config.ts b/astro.config.ts
index 704e41f..e1bc6cb 100644
--- a/astro.config.ts
+++ b/astro.config.ts
@@ -18,6 +18,7 @@ import { remarkReadingTime } from './src/plugins/remark-reading-time.mjs'
 
 const url = themeConfig.site.url
 const locale = themeConfig.global.locale
+const isKatexEnabled = themeConfig.global.katex
 const linkPrefetch = themeConfig.preload.linkPrefetch
 const imageHostURL = themeConfig.preload.imageHostURL
 const imageConfig = imageHostURL
@@ -31,6 +32,28 @@ const imageConfig = imageHostURL
     }
   : {}
 
+const remarkPlugins = [
+  remarkDirective,
+  ...(isKatexEnabled ? [remarkMath] : []),
+  remarkAdmonitions,
+  remarkGithubCard,
+  remarkReadingTime,
+]
+
+const rehypePlugins = [
+  rehypeSlug,
+  ...(isKatexEnabled ? [rehypeKatex] : []),
+  rehypeImgToFigure,
+  [
+    rehypeExternalLinks,
+    {
+      target: '_blank',
+      rel: ['nofollow', 'noopener', 'noreferrer', 'external'],
+      protocols: ['http', 'https', 'mailto'],
+    },
+  ],
+] as any[]
+
 export default defineConfig({
   site: url,
   base: '/',
@@ -61,26 +84,8 @@ export default defineConfig({
     robotsTxt(),
   ],
   markdown: {
-    remarkPlugins: [
-      remarkDirective,
-      remarkMath,
-      remarkAdmonitions,
-      remarkGithubCard,
-      remarkReadingTime,
-    ],
-    rehypePlugins: [
-      rehypeSlug,
-      rehypeKatex,
-      rehypeImgToFigure,
-      [
-        rehypeExternalLinks,
-        {
-          target: '_blank',
-          rel: ['nofollow', 'noopener', 'noreferrer', 'external'],
-          protocols: ['http', 'https', 'mailto'],
-        },
-      ],
-    ],
+    remarkPlugins,
+    rehypePlugins,
     shikiConfig: {
       // Available themes: https://shiki.style/themes
       themes: {
diff --git a/src/components/Widgets/BackToTop.astro b/src/components/Widgets/BackToTop.astro
index baaf2f3..721cfe3 100644
--- a/src/components/Widgets/BackToTop.astro
+++ b/src/components/Widgets/BackToTop.astro
@@ -60,18 +60,6 @@ function initBackToTop() {
   })
 }
 
-function cleanup() {
-  // Cleanup observer
-  if (observer) {
-    observer.disconnect()
-    observer = null
-  }
-
-  // Remove event listeners
-  backToTopButton = null
-}
-
 // Handle page transitions
 document.addEventListener('astro:page-load', initBackToTop)
-document.addEventListener('astro:before-swap', cleanup)
 </script>
diff --git a/src/components/Widgets/GithubCard.astro b/src/components/Widgets/GithubCard.astro
index e7ee6a2..bc80520 100644
--- a/src/components/Widgets/GithubCard.astro
+++ b/src/components/Widgets/GithubCard.astro
@@ -11,7 +11,7 @@ function setupGithubCards() {
         observer.unobserve(entry.target)
       }
     })
-  }, { rootMargin: '200px' })
+  }, { rootMargin: '400px' })
 
   githubCards.forEach(card => observer.observe(card))
 }
diff --git a/src/components/Widgets/PhotoSwipe.astro b/src/components/Widgets/PhotoSwipe.astro
index 2a2039e..a6202a0 100644
--- a/src/components/Widgets/PhotoSwipe.astro
+++ b/src/components/Widgets/PhotoSwipe.astro
@@ -53,11 +53,13 @@ function setupPhotoSwipe() {
 }
 
 function lazySetupPhotoSwipe() {
-  if ('requestIdleCallback' in window) {
+  if (typeof window.requestIdleCallback === 'function') {
     window.requestIdleCallback(() => setupPhotoSwipe(), { timeout: 1000 })
   }
   else {
-    setTimeout(setupPhotoSwipe, 100)
+    requestAnimationFrame(() => {
+      setupPhotoSwipe()
+    })
   }
 }
 
diff --git a/src/components/Widgets/Scrollbar.astro b/src/components/Widgets/Scrollbar.astro
index 0b62be5..70dd177 100644
--- a/src/components/Widgets/Scrollbar.astro
+++ b/src/components/Widgets/Scrollbar.astro
@@ -24,43 +24,54 @@ function setupScrollbar() {
     bodyElement.setAttribute('data-scrollbar-initialized', 'true')
   }
 
-  // Add scrollbar to code blocks
-  const preElements = document.querySelectorAll('pre')
-  preElements.forEach((pre) => {
-    if (!pre.hasAttribute('data-scrollbar-initialized')) {
+  const setupSecondaryScrollbars = () => {
+    // Add scrollbar to TOC content
+    const tocElement = document.getElementById('toc-content')
+    if (tocElement && !tocElement.hasAttribute('data-scrollbar-initialized')) {
       OverlayScrollbars({
-        target: pre,
+        target: tocElement,
       }, {
         scrollbars: {
           theme: 'scrollbar-widget',
-          autoHide: 'leave',
-          autoHideDelay: 500,
+          autoHide: 'never',
         },
         overflow: {
-          y: 'hidden',
+          x: 'hidden',
         },
       })
 
-      pre.setAttribute('data-scrollbar-initialized', 'true')
+      tocElement.setAttribute('data-scrollbar-initialized', 'true')
     }
-  })
 
-  // Add scrollbar to TOC content
-  const tocElement = document.getElementById('toc-content')
-  if (tocElement && !tocElement.hasAttribute('data-scrollbar-initialized')) {
-    OverlayScrollbars({
-      target: tocElement,
-    }, {
-      scrollbars: {
-        theme: 'scrollbar-widget',
-        autoHide: 'never',
-      },
-      overflow: {
-        x: 'hidden',
-      },
+    // Add scrollbar to code blocks
+    const preElements = document.querySelectorAll('pre')
+    preElements.forEach((pre) => {
+      if (!pre.hasAttribute('data-scrollbar-initialized')) {
+        OverlayScrollbars({
+          target: pre,
+        }, {
+          scrollbars: {
+            theme: 'scrollbar-widget',
+            autoHide: 'leave',
+            autoHideDelay: 500,
+          },
+          overflow: {
+            y: 'hidden',
+          },
+        })
+
+        pre.setAttribute('data-scrollbar-initialized', 'true')
+      }
     })
+  }
 
-    tocElement.setAttribute('data-scrollbar-initialized', 'true')
+  if (typeof window.requestIdleCallback === 'function') {
+    window.requestIdleCallback(setupSecondaryScrollbars, { timeout: 1000 })
+  }
+  else {
+    requestAnimationFrame(() => {
+      setupSecondaryScrollbars()
+    })
   }
 }
 
diff --git a/src/layouts/Head.astro b/src/layouts/Head.astro
index b7f6396..7c6c88a 100644
--- a/src/layouts/Head.astro
+++ b/src/layouts/Head.astro
@@ -54,7 +54,7 @@ const pageImage = postSlug
 <link rel="preload" href="/fonts/EarlySummer-Subset.woff2" as="font" type="font/woff2" crossorigin />
 <link rel="preload" href="/fonts/Snell-Black.woff2" as="font" type="font/woff2" crossorigin />
 <link rel="preload" href="/fonts/Snell-Bold.woff2" as="font" type="font/woff2" crossorigin />
-{katex && <link rel="stylesheet" href={katexCSS} />}
+{katex && <link rel="preload" href={katexCSS} as="style" onload="this.onload=null;this.rel='stylesheet'" />}
 {commentURL && <link rel="preconnect" href={commentURL} crossorigin />}
 {commentURL && <link rel="dns-prefetch" href={commentURL} />}
 <link rel="alternate" href="/rss.xml" type="application/rss+xml" title="RSS Feed" />