diff --git a/content/posts/reflection.md b/content/posts/reflection.md
index 280d1f9..d7dd327 100644
--- a/content/posts/reflection.md
+++ b/content/posts/reflection.md
@@ -6,7 +6,7 @@ original_url: "https://aztec-project.org/blog/reflection.html"
 archive_url: "https://web.archive.org/web/20250114131122/https://aztec-project.org/blog/reflection.html"
 author: "Thomas Christian"
 categories: ["How-To"]
-tags: ["Assemblies", "Assemby", "C#", "Reflection"]
+tags: ["Assemblies", "Assembly", "C#", "Reflection"]
 ---
 
 ## Vorbereitung
diff --git a/hugo.toml b/hugo.toml
index 6f9b1bf..72a84d1 100644
--- a/hugo.toml
+++ b/hugo.toml
@@ -12,6 +12,7 @@ paginate = 10
 [params]
   subtitle = "but we can fix it! Sometimes :)"
   bannerImage = "/images/banner.jpg"
+  description = "build broken – Das Blog-Archiv des .NET-/Softwareentwicklungs-Blogs (2009–2010): Artikel zu Clean Code, ASP.NET, MVC, MVP, WinForms, StupidDB, NoSQL, Scrum und mehr. Von Stefan Kölle, Christina Hirth, Thomas Christian und Andreas Seebauer."
 
 [markup.goldmark.renderer]
   unsafe = true
diff --git a/layouts/_default/404.html b/layouts/_default/404.html
new file mode 100644
index 0000000..aeb787c
--- /dev/null
+++ b/layouts/_default/404.html
@@ -0,0 +1,9 @@
+{{ define "main" }}
+<article class="post">
+  <div class="post-body">
+    <h1 class="post-title">Seite nicht gefunden</h1>
+    <p>Die angeforderte Seite existiert nicht (mehr). Möglicherweise ist der Artikel umgezogen.</p>
+    <p><a href="{{ "/" | relURL }}">&larr; Zurück zur Startseite</a></p>
+  </div>
+</article>
+{{ end }}
diff --git a/layouts/_default/baseof.html b/layouts/_default/baseof.html
index ccae5ae..11ab83f 100644
--- a/layouts/_default/baseof.html
+++ b/layouts/_default/baseof.html
@@ -4,6 +4,26 @@
   <meta charset="utf-8">
   <title>{{ if .IsHome }}{{ .Site.Title }}{{ else }}{{ .Title }} | {{ .Site.Title }}{{ end }}</title>
   <meta name="viewport" content="width=device-width, initial-scale=1">
+  {{- $title := cond .IsHome .Site.Title .Title }}
+  {{- $desc := "" }}
+  {{- if .IsHome }}{{ $desc = .Site.Params.description }}{{ else }}{{ $desc = .Description }}{{ end }}
+  {{- if not $desc }}{{ $desc = .Summary | plainify }}{{ end }}
+  {{- $desc = strings.TrimSpace (strings.TrimRight "…" $desc) | truncate 160 }}
+  {{- if $desc }}<meta name="description" content="{{ $desc }}">{{ end }}
+  <link rel="canonical" href="{{ .Permalink }}">
+  <meta property="og:type" content="{{ if .IsHome }}website{{ else }}article{{ end }}">
+  <meta property="og:site_name" content="{{ .Site.Title }}">
+  <meta property="og:title" content="{{ $title }}">
+  <meta property="og:url" content="{{ .Permalink }}">
+  {{- if $desc }}<meta property="og:description" content="{{ $desc }}">{{ end }}
+  {{- if .Params.images }}
+  {{- range .Params.images }}<meta property="og:image" content="{{ . | absURL }}">{{ end }}
+  {{- else }}<meta property="og:image" content="{{ .Site.Params.bannerImage | absURL }}">{{ end }}
+  {{- if not .IsHome }}{{ with .Date }}<meta property="article:published_time" content="{{ .Format "2006-01-02T15:04:05Z07:00" }}">{{ end }}{{ end }}
+  <meta name="twitter:card" content="summary_large_image">
+  <meta name="twitter:title" content="{{ $title }}">
+  {{- if $desc }}<meta name="twitter:description" content="{{ $desc }}">{{ end }}
+  <meta name="twitter:image" content="{{ .Site.Params.bannerImage | absURL }}">
   <link rel="icon" type="image/svg+xml" href="{{ "favicon.svg" | relURL }}">
   <link rel="stylesheet" href="{{ "css/style.css" | relURL }}">
 </head>