diff --git a/src/client/theme-default/components/VPSidebar.vue b/src/client/theme-default/components/VPSidebar.vue
index 7602d68b..f39a7d99 100644
--- a/src/client/theme-default/components/VPSidebar.vue
+++ b/src/client/theme-default/components/VPSidebar.vue
@@ -94,7 +94,7 @@ watchPostEffect(async () => {
 
 @media (min-width: 1440px) {
   .VPSidebar {
-    padding-left: calc((100% - (var(--vp-layout-max-width) - 64px)) / 2);
+    padding-left: max(32px, calc((100% - (var(--vp-layout-max-width) - 64px)) / 2));
     width: calc((100% - (var(--vp-layout-max-width) - 64px)) / 2 + var(--vp-sidebar-width) - 32px);
   }
 }
diff --git a/src/client/theme-default/styles/components/vp-doc.css b/src/client/theme-default/styles/components/vp-doc.css
index 29128d3a..c8c64a94 100644
--- a/src/client/theme-default/styles/components/vp-doc.css
+++ b/src/client/theme-default/styles/components/vp-doc.css
@@ -222,7 +222,7 @@
 
 .vp-doc .custom-block div[class*='language-'] code {
   font-weight: 400;
-  background-color: var(--vp-code-block-bg);
+  background-color: transparent;
 }
 
 /**
diff --git a/src/node/serve/serve.ts b/src/node/serve/serve.ts
index 107b0ad6..ec27a2ef 100644
--- a/src/node/serve/serve.ts
+++ b/src/node/serve/serve.ts
@@ -1,3 +1,5 @@
+import fs from 'fs'
+import path from 'path'
 import sirv from 'sirv'
 import compression from 'compression'
 import polka from 'polka'
@@ -26,14 +28,21 @@ export async function serve(options: ServeOptions = {}) {
   const site = await resolveConfig(options.root, 'serve', 'production')
   const base = trimChar(options?.base ?? site?.site?.base ?? '', '/')
 
+  const notAnAsset = (pathname: string) => !pathname.includes('/assets/')
+  const notFound = fs.readFileSync(path.resolve(site.outDir, './404.html'))
+  const onNoMatch: polka.Options['onNoMatch'] = (req, res) => {
+    res.statusCode = 404
+    if (notAnAsset(req.path)) res.write(notFound.toString())
+    res.end()
+  }
+
   const compress = compression()
   const serve = sirv(site.outDir, {
     etag: true,
-    single: true,
     maxAge: 31536000,
     immutable: true,
     setHeaders(res, pathname) {
-      if (!pathname.includes('/assets/')) {
+      if (notAnAsset(pathname)) {
         // force server validation for non-asset files since they
         // are not fingerprinted
         res.setHeader('cache-control', 'no-cache')
@@ -42,14 +51,14 @@ export async function serve(options: ServeOptions = {}) {
   })
 
   if (base) {
-    polka()
+    polka({ onNoMatch })
       .use(base, compress, serve)
       .listen(port, (err: any) => {
         if (err) throw err
         console.log(`Built site served at http://localhost:${port}/${base}/\n`)
       })
   } else {
-    polka()
+    polka({ onNoMatch })
       .use(compress, serve)
       .listen(port, (err: any) => {
         if (err) throw err
diff --git a/src/shared/shared.ts b/src/shared/shared.ts
index 8e02e6dc..973a4a03 100644
--- a/src/shared/shared.ts
+++ b/src/shared/shared.ts
@@ -21,7 +21,7 @@ export const notFoundPageData: PageData = {
   title: '404',
   description: 'Not Found',
   headers: [],
-  frontmatter: {},
+  frontmatter: { sidebar: false, layout: 'page' },
   lastUpdated: 0
 }