diff --git a/app/categories/[categorySlug]/page.tsx b/app/(withRecent)/categories/[categorySlug]/page.tsx
similarity index 81%
rename from app/categories/[categorySlug]/page.tsx
rename to app/(withRecent)/categories/[categorySlug]/page.tsx
index 58e8eec..fbf602c 100644
--- a/app/categories/[categorySlug]/page.tsx
+++ b/app/(withRecent)/categories/[categorySlug]/page.tsx
@@ -16,6 +16,13 @@ export async function generateMetadata({ params }: CategoryPageProps): Promise<M
   return {
     title: `${category} | ${metadata.title!.toString()}`,
     description: 'List of posts in this category',
+    openGraph: {
+      type: 'website',
+      title: `${category} | ${metadata.title!.toString()}`,
+      description: 'List of posts in this category',
+      url: process.env.SITE_URL + `/categories/${categorySlug}`,
+      siteName: metadata.title!.toString(),
+    },
   }
 }
 
diff --git a/app/(withRecent)/categories/page.tsx b/app/(withRecent)/categories/page.tsx
new file mode 100644
index 0000000..474aa4a
--- /dev/null
+++ b/app/(withRecent)/categories/page.tsx
@@ -0,0 +1,77 @@
+import { getAllCategories } from '@/lib/categories'
+import { getAllPostsMeta } from '@/lib/posts'
+import { slugify } from '@/utils/slug'
+import type { Metadata } from 'next'
+import Link from 'next/link'
+import { metadata } from '@/app/metadata'
+import { dateFormatter } from '@/utils/time'
+import { RecentlyUpdatedPosts } from '@/components/common/RecentlyUpdatedPosts'
+
+export async function generateMetadata(): Promise<Metadata> {
+  return {
+    title: `Categories | ${metadata.title!.toString()}`,
+    description: 'List of categories',
+    openGraph: {
+      type: 'website',
+      title: `Categories | ${metadata.title!.toString()}`,
+      description: 'List of categories',
+      url: process.env.SITE_URL + '/categories',
+      siteName: metadata.title!.toString(),
+    },
+  }
+}
+
+export default function CategoriesPage() {
+  const categories = getAllCategories()
+  const posts = getAllPostsMeta()
+  const categoryNames = Object.keys(categories)
+
+  return (
+    <main className="max-w-3xl mx-auto px-4 py-8 lg:py-16 w-full">
+      <div className="text-sm text-fg-dim mb-2">~/categories</div>
+
+      <ul className="border-l border-neutral-800 ml-1">
+        {categoryNames.map((category) => {
+          const categoryPosts = posts.filter((post) => post.category === category)
+
+          return (
+            <li key={category} className="pl-5">
+              <Link
+                href={`/categories/${slugify(category)}`}
+                className="group flex items-baseline gap-2 py-2 px-2 -ml-2 hover:bg-accent/10 transition-colors"
+              >
+                <span className="font-bold group-hover:text-accent transition-colors">
+                  {category}
+                </span>
+                <span className="font-mono text-xs text-neutral-600">({categoryPosts.length})</span>
+              </Link>
+
+              <ul className="border-l border-neutral-800 ml-3 mb-3">
+                {categoryPosts.map((post) => (
+                  <li key={post.slug} className="pl-5">
+                    <Link
+                      href={`/posts/${post.slug}`}
+                      className="group flex items-baseline justify-between gap-3 py-1.5 px-2 -ml-2 border-l-2 border-transparent hover:bg-accent/10 hover:border-accent transition-colors"
+                    >
+                      <span className="group-hover:text-accent transition-colors truncate">
+                        {post.title}
+                      </span>
+                      {post.date && (
+                        <time
+                          dateTime={new Date(post.date).toISOString()}
+                          className="text-sm whitespace-nowrap"
+                        >
+                          {dateFormatter.format(new Date(post.date))}
+                        </time>
+                      )}
+                    </Link>
+                  </li>
+                ))}
+              </ul>
+            </li>
+          )
+        })}
+      </ul>
+    </main>
+  )
+}
diff --git a/app/(withRecent)/layout.tsx b/app/(withRecent)/layout.tsx
new file mode 100644
index 0000000..0a1041f
--- /dev/null
+++ b/app/(withRecent)/layout.tsx
@@ -0,0 +1,10 @@
+import { RecentlyUpdatedPosts } from '@/components/common/RecentlyUpdatedPosts'
+
+export default function WithRecentLayout({ children }: { children: React.ReactNode }) {
+  return (
+    <>
+      {children}
+      <RecentlyUpdatedPosts />
+    </>
+  )
+}
diff --git a/app/(withRecent)/page.tsx b/app/(withRecent)/page.tsx
new file mode 100644
index 0000000..8fa0f5a
--- /dev/null
+++ b/app/(withRecent)/page.tsx
@@ -0,0 +1,41 @@
+import { getAllPostsMeta } from '@/lib/posts'
+import { Post } from '@/components/common/Post'
+
+export default function BlogIndex() {
+  const posts = getAllPostsMeta()
+
+  const rest = posts.slice(1)
+  const rows = []
+  for (let i = 0; i < rest.length; i += 2) {
+    rows.push(rest.slice(i, i + 2))
+  }
+
+  return (
+    <main className="max-w-3xl mx-auto px-4 py-8 lg:py-16">
+      <section>
+        {posts.length === 0 ? (
+          <div className="rounded-xl border border-border p-6 text-fg-dim">
+            No published posts yet.
+          </div>
+        ) : (
+          <>
+            <Post post={posts[0]} isLatest />
+            <div className="border-t border-border my-6" aria-hidden="true"></div>
+            <div className="flex flex-col gap-8 mt-4">
+              {rows.map((row) => {
+                const rowHasImage = row.some((p) => p.coverImage)
+                return (
+                  <div key={row[0].slug} className="grid grid-cols-1 gap-4 md:grid-cols-2">
+                    {row.map((post) => (
+                      <Post post={post} key={post.slug} showImageSlot={rowHasImage} />
+                    ))}
+                  </div>
+                )
+              })}
+            </div>
+          </>
+        )}
+      </section>
+    </main>
+  )
+}
diff --git a/app/categories/page.tsx b/app/categories/page.tsx
deleted file mode 100644
index 73ddf6f..0000000
--- a/app/categories/page.tsx
+++ /dev/null
@@ -1,43 +0,0 @@
-import { getAllCategories } from '@/lib/categories'
-import { getAllPostsMeta } from '@/lib/posts'
-import { slugify } from '@/utils/slug'
-import type { Metadata } from 'next'
-import Link from 'next/link'
-import { metadata } from '@/app/metadata'
-
-export async function generateMetadata(): Promise<Metadata> {
-  return { title: `Categories | ${metadata.title!.toString()}`, description: 'List of categories' }
-}
-
-export default function CategoriesPage() {
-  const categories = getAllCategories()
-  const posts = getAllPostsMeta()
-
-  return (
-    <div className="flex w-full">
-      <main className="max-w-3xl mx-auto px-4 py-8 lg:py-16 w-full">
-        <h1 className="text-3xl font-bold">Categories</h1>
-        <ul>
-          {Object.keys(categories).map((category) => (
-            <li key={category}>
-              <Link href={`/categories/${slugify(category)}`}>
-                {category} ({categories[category]})
-              </Link>
-
-              <ul>
-                {posts
-                  .filter((post) => post.category === category)
-                  .map((post) => (
-                    <li key={post.slug}>
-                      <Link href={`/posts/${post.slug}`}>{post.title}</Link>
-                    </li>
-                  ))}
-              </ul>
-            </li>
-          ))}
-        </ul>
-      </main>
-      <div className="w-80" />
-    </div>
-  )
-}
diff --git a/app/globals.css b/app/globals.css
index fd6949c..0eb6f0a 100644
--- a/app/globals.css
+++ b/app/globals.css
@@ -43,7 +43,8 @@ body {
     @apply list-decimal;
   }
 
-  ul, ol {
+  ul,
+  ol {
     @apply list-outside;
   }
 
@@ -151,7 +152,7 @@ dd {
 }
 
 .prose a {
-  @apply text-accent;
+  @apply text-accent hover:underline focus:underline cursor-pointer;
 }
 
 .prose ul:not(.task-list-container) {
diff --git a/app/metadata.ts b/app/metadata.ts
new file mode 100644
index 0000000..de2bbea
--- /dev/null
+++ b/app/metadata.ts
@@ -0,0 +1,14 @@
+import { Metadata } from "next";
+
+export const metadata: Metadata = {
+  title: "Ephemeris",
+  description: "A blog about me and my interests",
+  creator: "hangerthem",
+  openGraph: {
+    type: "website",
+    title: "Ephemeris",
+    description: "A blog about me and my interests",
+    url: process.env.SITE_URL,
+    siteName: "Ephemeris",
+  },
+}
\ No newline at end of file
diff --git a/app/metadata.tsx b/app/metadata.tsx
deleted file mode 100644
index cbb1393..0000000
--- a/app/metadata.tsx
+++ /dev/null
@@ -1,7 +0,0 @@
-import { Metadata } from "next";
-
-export const metadata: Metadata = {
-  title: "Ephemeris",
-  description: "A blog about me and my interests",
-  creator: "hangerthem",
-}
\ No newline at end of file
diff --git a/app/page.tsx b/app/page.tsx
deleted file mode 100644
index a70dec9..0000000
--- a/app/page.tsx
+++ /dev/null
@@ -1,63 +0,0 @@
-import { getAllPostsMeta } from '@/lib/posts'
-import { Post } from '@/components/common/Post'
-import Link from 'next/link'
-
-export default function BlogIndex() {
-  const posts = getAllPostsMeta()
-
-  const rest = posts.slice(1)
-  const rows = []
-  for (let i = 0; i < rest.length; i += 2) {
-    rows.push(rest.slice(i, i + 2))
-  }
-
-  return (
-    <>
-      <main className="max-w-3xl mx-auto px-4 py-8 lg:py-16">
-        <section>
-          {posts.length === 0 ? (
-            <div className="rounded-xl border border-border p-6 text-fg-dim">
-              No published posts yet.
-            </div>
-          ) : (
-            <>
-              <Post post={posts[0]} isLatest />
-              <div className="border-t border-border my-6" aria-hidden="true"></div>
-              <div className="flex flex-col gap-8 mt-4">
-                {rows.map((row) => {
-                  const rowHasImage = row.some((p) => p.coverImage)
-                  return (
-                    <div key={row[0].slug} className="grid grid-cols-1 gap-4 md:grid-cols-2">
-                      {row.map((post) => (
-                        <Post post={post} key={post.slug} showImageSlot={rowHasImage} />
-                      ))}
-                    </div>
-                  )
-                })}
-              </div>
-            </>
-          )}
-        </section>
-      </main>
-      <aside className="w-80 hidden lg:block px-4 py-8 lg:py-16">
-        <div className="sticky top-8">
-          <h2 className="text-xl font-bold mb-4">Recently updated</h2>
-          <ul className="flex flex-col gap-2 ml-2">
-            {posts
-              .toSorted(
-                (a, b) =>
-                  new Date(b.updated ?? b.date).getTime() - new Date(a.updated ?? a.date).getTime(),
-              )
-              .map((post) => (
-                <li key={post.slug} className="text-sm text-fg-dim">
-                  <Link href={`/posts/${post.slug}`} className="hover:underline">
-                    {post.title}
-                  </Link>
-                </li>
-              ))}
-          </ul>
-        </div>
-      </aside>
-    </>
-  )
-}
diff --git a/app/posts/[slug]/page.tsx b/app/posts/[slug]/page.tsx
index b9870fe..151e2ac 100644
--- a/app/posts/[slug]/page.tsx
+++ b/app/posts/[slug]/page.tsx
@@ -2,7 +2,8 @@ import { metadata } from '@/app/metadata'
 import { ImageWrapper } from '@/components/common/ImageWrapper'
 import { ShareLinks } from '@/components/common/ShareLinks'
 import { TableOfContents } from '@/components/common/TableOfContents'
-import { getAllPostSlugs, getPostBySlug } from '@/lib/posts'
+import { getAllPostSlugs, getNextAndPreviousPosts, getPostBySlug } from '@/lib/posts'
+import { slugify } from '@/utils/slug'
 import type { Metadata } from 'next'
 import Link from 'next/link'
 
@@ -19,19 +20,33 @@ export async function generateMetadata({
 }): Promise<Metadata> {
   const { slug } = await params
   const { meta } = await getPostBySlug(slug)
-  return { title: `${meta.title}  | ${metadata.title!.toString()}`, description: meta.description }
+  return {
+    title: `${meta.title} | ${metadata.title!.toString()}`,
+    description: meta.description,
+    openGraph: {
+      type: 'article',
+      title: `${meta.title} | ${metadata.title!.toString()}`,
+      description: meta.description,
+      url: process.env.SITE_URL + `/posts/${slug}`,
+      images: meta.coverImage ? [meta.coverImage] : undefined,
+      tags: meta.tags,
+      ...(meta.updated && { modifiedTime: new Date(meta.updated).toISOString() }),
+      siteName: metadata.title!.toString(),
+    },
+  }
 }
 
 export default async function Post({ params }: { params: Promise<{ slug: string }> }) {
   const { slug } = await params
   const { meta, content, tableOfContents } = await getPostBySlug(slug)
+  const { next, previous } = getNextAndPreviousPosts(slug)
 
   return (
     <main className="flex w-full">
       <article className="max-w-3xl mx-auto px-4 py-8 lg:py-16">
         {meta.category && (
           <Link
-            href={`/categories/${meta.category.toLowerCase()}`}
+            href={`/categories/${slugify(meta.category)}`}
             className="text-accent hover:underline font-sm mb-2 block"
           >
             {meta.category}
@@ -99,6 +114,29 @@ export default async function Post({ params }: { params: Promise<{ slug: string
             description={meta.description}
           />
         </div>
+
+        <div className="mt-8 flex justify-between">
+          {previous ? (
+            <Link
+              href={`/posts/${previous.slug}`}
+              className="text-accent hover:underline font-sm mb-2 block"
+            >
+              &larr; {previous.title}
+            </Link>
+          ) : (
+            <div />
+          )}
+          {next ? (
+            <Link
+              href={`/posts/${next.slug}`}
+              className="text-accent hover:underline font-sm mb-2 block"
+            >
+              {next.title} &rarr;
+            </Link>
+          ) : (
+            <div />
+          )}
+        </div>
       </article>
 
       <aside className="hidden lg:block w-80">
diff --git a/components/common/CodeWrapper.tsx b/components/common/CodeWrapper.tsx
index f5c7d85..0ec48c1 100644
--- a/components/common/CodeWrapper.tsx
+++ b/components/common/CodeWrapper.tsx
@@ -1,22 +1,11 @@
 'use client'
 
-import { isValidElement, type ReactNode } from 'react'
 import { CopyButton } from './CopyButton'
+import { getTextContent } from '@/lib/react-node-text'
 
 type CodeWrapperProps = {
   language?: string
-  children?: ReactNode
-}
-
-function getTextContent(node: ReactNode): string {
-  if (node === null || typeof node === 'boolean') return ''
-  if (typeof node === 'string' || typeof node === 'number') return String(node)
-  if (Array.isArray(node)) return node.map(getTextContent).join('')
-  if (isValidElement(node)) {
-    const props = node.props as { children?: ReactNode }
-    return getTextContent(props.children)
-  }
-  return ''
+  children?: React.ReactNode
 }
 
 export function CodeWrapper({ language, children }: CodeWrapperProps) {
diff --git a/components/common/ExternalLink.tsx b/components/common/ExternalLink.tsx
index c2f5e17..480b57a 100644
--- a/components/common/ExternalLink.tsx
+++ b/components/common/ExternalLink.tsx
@@ -1,20 +1,12 @@
-import type { AnchorHTMLAttributes } from 'react';
-import { cn } from '@/utils/cn';
+import type { AnchorHTMLAttributes } from 'react'
 
 type ExternalLinkProps = Omit<
   AnchorHTMLAttributes<HTMLAnchorElement>,
   'href' | 'rel' | 'target'
 > & {
-  href: string;
-};
-
-export function ExternalLink({ className, ...props }: ExternalLinkProps) {
-  return (
-    <a
-      {...props}
-      className={cn(className, 'hover:underline focus:underline')}
-      target="_blank"
-      rel="noopener noreferrer"
-    />
-  );
+  href: string
+}
+
+export function ExternalLink(props: ExternalLinkProps) {
+  return <a {...props} target="_blank" rel="noopener noreferrer" />
 }
diff --git a/components/common/RecentlyUpdatedPosts.tsx b/components/common/RecentlyUpdatedPosts.tsx
new file mode 100644
index 0000000..3dec17e
--- /dev/null
+++ b/components/common/RecentlyUpdatedPosts.tsx
@@ -0,0 +1,27 @@
+import { getAllPostsMeta } from '@/lib/posts'
+import Link from 'next/link'
+
+export function RecentlyUpdatedPosts() {
+  const posts = getAllPostsMeta()
+  return (
+    <aside className="w-80 hidden lg:block py-4 lg:py-12">
+      <div className="sticky top-8 border-l border-border h-fit pl-4 py-4">
+        <h2 className="text-xl font-bold mb-4">Recently updated</h2>
+        <ul className="flex flex-col gap-2 ml-1">
+          {posts
+            .toSorted(
+              (a, b) =>
+                new Date(b.updated ?? b.date).getTime() - new Date(a.updated ?? a.date).getTime(),
+            )
+            .map((post) => (
+              <li key={post.slug} className="text-sm text-fg-dim">
+                <Link href={`/posts/${post.slug}`} className="hover:underline">
+                  {post.title}
+                </Link>
+              </li>
+            ))}
+        </ul>
+      </div>
+    </aside>
+  )
+}
diff --git a/components/layout/NavLinks.tsx b/components/layout/NavLinks.tsx
index b1332b9..8618cc0 100644
--- a/components/layout/NavLinks.tsx
+++ b/components/layout/NavLinks.tsx
@@ -1,16 +1,16 @@
 'use client'
 
 import { cn } from '@/utils/cn'
-import { Folder, Home, Info, Rss, Tags } from 'lucide-react'
+import { Folder, GitBranch, Home, Info, Rss, Tags } from 'lucide-react'
 import Link from 'next/link'
 import { usePathname } from 'next/navigation'
+import { ExternalLink } from '../common/ExternalLink'
 
 type NavItem = {
   href: string
   label: string
   icon: React.ReactNode
-  target?: string
-  rel?: string
+  isExternal?: boolean
 }
 
 const navItems: NavItem[] = [
@@ -22,8 +22,13 @@ const navItems: NavItem[] = [
     href: '/feed.xml',
     label: 'RSS Feed',
     icon: <Rss className="w-4 h-4" />,
-    target: '_blank',
-    rel: 'noopener noreferrer',
+    isExternal: true,
+  },
+  {
+    href: 'https://git.hangerthem.com/hangerthem/blog.hangerthem.com',
+    label: 'Source Code',
+    icon: <GitBranch className="w-4 h-4" />,
+    isExternal: true,
   },
 ]
 
@@ -45,15 +50,20 @@ export function NavLinks() {
         isActive(item.href) ? 'text-fg bg-fg/25' : 'text-fg-dim hover:text-fg hover:bg-fg/10',
       )}
     >
-      <Link
-        href={item.href}
-        className="flex items-center gap-2 px-2 py-1"
-        target={item.target}
-        rel={item.rel}
-      >
-        {item.icon}
-        {item.label}
-      </Link>
+      {item.isExternal ? (
+        <ExternalLink
+          href={item.href}
+          className="flex items-center gap-2 px-2 py-1 hover:no-underline focus:no-underline"
+        >
+          {item.icon}
+          {item.label}
+        </ExternalLink>
+      ) : (
+        <Link href={item.href} className="flex items-center gap-2 px-2 py-1">
+          {item.icon}
+          {item.label}
+        </Link>
+      )}
     </li>
   ))
 }
diff --git a/content/posts/self-development.md b/content/posts/self-development.md
index 08d2bf0..a81d7d5 100644
--- a/content/posts/self-development.md
+++ b/content/posts/self-development.md
@@ -3,7 +3,7 @@ title: Self-Development and Gamification of Life
 description: In this post, I explore the concept of self-development and how gamification can be used to enhance productivity and personal growth. Learn how to turn your life into a game and level up your skills!
 author: hangerthem
 date: 2024-08-05 22:00:00 +0200
-category: "Personal Development"
+category: Personal Development
 tags: [self-development, gamification, productivity, growth]
 math: true
 mermaid: true
diff --git a/content/posts/standard-model.md b/content/posts/standard-model.md
index b2da1d0..2ad032d 100644
--- a/content/posts/standard-model.md
+++ b/content/posts/standard-model.md
@@ -264,12 +264,12 @@ $$
    - **$i \gamma^\mu D_\mu$** - Represents the kinetic term of the electrons, where $\gamma^\mu$ are the gamma matrices associated with the Dirac equation and $D_\mu$ is the covariant derivative.
    - **Covariant Derivative** ($D_\mu$):
 
-     $$
-     \begin{equation}
-     D_\mu = \partial_\mu - i e A_\mu
-     \label{eq:covariant_derivative_for_electrons}
-     \end{equation}
-     $$
+   $$
+   \begin{equation}
+   D_\mu = \partial_\mu - i e A_\mu
+   \label{eq:covariant_derivative_for_electrons}
+   \end{equation}
+   $$
 
    - **Explanation**: This accounts for the interaction of electrons with the electromagnetic field. $e$ is the electric charge, and $A_\mu$ is the electromagnetic potential.
 
@@ -301,21 +301,21 @@ $$
 
    - **$W$ Field Strength Tensor** ($W^a_{\mu\nu}$):
 
-     $$
-     \begin{equation}
-     W^a_{\mu\nu} = \partial_\mu W^a_\nu - \partial_\nu W^a_\mu + g \epsilon^{abc} W^b_\mu W^c_\nu
-     \label{eq:w_field_strength_tensor}
-     \end{equation}
-     $$
+   $$
+   \begin{equation}
+   W^a_{\mu\nu} = \partial_\mu W^a_\nu - \partial_\nu W^a_\mu + g \epsilon^{abc} W^b_\mu W^c_\nu
+   \label{eq:w_field_strength_tensor}
+   \end{equation}
+   $$
 
    - **$B$ Field Strength Tensor** ($B_{\mu\nu}$):
 
-     $$
-     \begin{equation}
-     B_{\mu\nu} = \partial_\mu B_\nu - \partial_\nu B_\mu
-     \label{eq:b_field_strength_tensor}
-     \end{equation}
-     $$
+   $$
+   \begin{equation}
+   B_{\mu\nu} = \partial_\mu B_\nu - \partial_\nu B_\mu
+   \label{eq:b_field_strength_tensor}
+   \end{equation}
+   $$
 
    - **Explanation**: These terms describe the field strengths of the $W$ and $B$ fields, which are associated with the weak and electromagnetic forces, respectively. The $W$ field strength tensor involves the non-Abelian field strength term, reflecting the non-Abelian nature of the weak force.
 
@@ -325,12 +325,12 @@ $$
    - **$i \gamma^\mu D_\mu$** - Represents the kinetic term of the leptons/quarks, where $\gamma^\mu$ are the gamma matrices associated with the Dirac equation and $D_\mu$ is the covariant derivative.
    - **Covariant Derivative** ($D_\mu$):
 
-     $$
-     \begin{equation}
-     D_\mu = \partial_\mu - i g' Y B_\mu - i g \frac{\tau^a}{2} W^a_\mu
-     \label{eq:covariant_derivative_for_leptons_quarks}
-     \end{equation}
-     $$
+   $$
+   \begin{equation}
+   D_\mu = \partial_\mu - i g' Y B_\mu - i g \frac{\tau^a}{2} W^a_\mu
+   \label{eq:covariant_derivative_for_leptons_quarks}
+   \end{equation}
+   $$
 
    - **Explanation**: This accounts for the interaction of leptons/quarks with the $W$ and $B$ fields. $g'$ and $g$ are the coupling constants for the $U(1)$ and $SU(2)$ gauge groups, respectively. $Y$ is the weak hypercharge, and $\frac{\tau^a}{2}$ are the generators of the $SU(2)$ group.
 
@@ -375,12 +375,12 @@ $$
    - **$i \gamma^\mu D_\mu$** - Represents the kinetic term of the quarks, where $\gamma^\mu$ are the gamma matrices associated with the Dirac equation and $D_\mu$ is the covariant derivative.
    - **Covariant Derivative** ($D_\mu$):
 
-     $$
-     \begin{equation}
-     D_\mu = \partial_\mu - i g_s \frac{\lambda^a}{2} G^a_\mu
-     \label{eq:quark_covariant_derivative_qcd}
-     \end{equation}
-     $$
+   $$
+   \begin{equation}
+   D_\mu = \partial_\mu - i g_s \frac{\lambda^a}{2} G^a_\mu
+   \label{eq:quark_covariant_derivative_qcd}
+   \end{equation}
+   $$
 
    - **Explanation**: This accounts for the interaction of quarks with gluons. $g_s$ is the strong coupling constant, and $\frac{\lambda^a}{2}$ are the generators of the SU(3) color gauge group. $G^a_\mu$ are the gluon fields.
 
diff --git a/content/posts/test-post.md b/content/posts/test-post.md
index c52b90a..632de5b 100644
--- a/content/posts/test-post.md
+++ b/content/posts/test-post.md
@@ -72,8 +72,9 @@ $$
 
 ---
 
-[this is a link](https://example.com)
+this is an [external link](https://example.com)
 
+and this is an [internal link](/about)
 
 ```mermaid
 graph TD;
diff --git a/lib/posts.tsx b/lib/posts.tsx
index d1f9898..dd43df9 100644
--- a/lib/posts.tsx
+++ b/lib/posts.tsx
@@ -18,27 +18,18 @@ import { ExternalLink } from '@/components/common/ExternalLink'
 import readingTime from 'reading-time'
 import { rehypeUnwrapImages } from './rehype-unwrap-images'
 import { rehypeMermaidSsg } from './rehype-mermaid-ssg'
-import { stripLeadingMatch } from './react-node-text'
+import { getTextContent, stripLeadingMatch } from './react-node-text'
 import { BlockquoteWrapper } from '@/components/common/BlockquoteWrapper'
 import type { NoteType } from '@/types/Note.type'
 import { rehypeMark } from './rehype-mark'
 import { rehypeDefinition } from './rehype-definition'
 import { slugify } from '@/utils/slug'
 import { PostMeta } from '@/types/Post.type'
+import Link from 'next/link'
+import { ExternalLinkIcon } from 'lucide-react'
 
 const postsDirectory = path.join(process.cwd(), 'content/posts')
 
-function getTextContent(node: ReactNode): string {
-  if (typeof node === 'string') return node
-  if (typeof node === 'number') return String(node)
-  if (Array.isArray(node)) return node.map(getTextContent).join('')
-  if (node && typeof node === 'object' && 'props' in node) {
-    const props = node.props as { children?: ReactNode }
-    return getTextContent(props.children)
-  }
-  return ''
-}
-
 export function getAllPostSlugs(): string[] {
   return fs
     .readdirSync(postsDirectory)
@@ -60,6 +51,17 @@ export function getAllPostsMeta(): PostMeta[] {
     .toSorted((a, b) => (a.date < b.date ? 1 : -1))
 }
 
+export function getNextAndPreviousPosts(slug: string): {
+  next: PostMeta | null
+  previous: PostMeta | null
+} {
+  const posts = getAllPostsMeta()
+  const index = posts.findIndex((post) => post.slug === slug)
+  const next = index < posts.length - 1 ? posts[index + 1] : null
+  const previous = index > 0 ? posts[index - 1] : null
+  return { next, previous }
+}
+
 export async function getPostBySlug(slug: string) {
   const fullPath = path.join(postsDirectory, `${slug}.md`)
   const { data, content } = matter(fs.readFileSync(fullPath, 'utf8'))
@@ -98,9 +100,12 @@ export async function getPostBySlug(slug: string) {
       img: ({ src, alt }: { src: string; alt: string }) => <ImageWrapper src={src} alt={alt} />,
       a: ({ href, children }: { href: string; children: ReactNode }) =>
         href?.startsWith('http') ? (
-          <ExternalLink href={href}>{children}</ExternalLink>
+          <ExternalLink href={href}>
+            {children}
+            <ExternalLinkIcon className="inline-block w-3 h-3 ml-1" />
+          </ExternalLink>
         ) : (
-          <a href={href}>{children}</a>
+          <Link href={href}>{children}</Link>
         ),
       blockquote: ({ children }: { children: ReactNode }) => {
         const textContent = getTextContent(children).trimStart()