update related-post functionality, 404 page, and readme file

layouts/404.html

@@ -1,20 +1,24 @@
 {{ define "main" }}
-  {{ with site.GetPage "404" }}
-    <section class="section-sm text-center">
-      <div class="container">
-        <div class="row justify-center">
-          <div class="sm:col-10 md:col-8 lg:col-6">
-            {{ partial "image" (dict "Src" .Params.image "Alt" .Title "Class" "mb-8") }}
-            <h1 class="h2 mb-4">{{ .Title }}</h1>
-            <div class="content">
-              {{ .Content }}
-            </div>
-            <a href="{{ site.BaseURL }}" class="btn btn-primary mt-8">
-              {{ i18n "back_to_home" }}
-            </a>
+  <section class="section-sm text-center">
+    <div class="container">
+      <div class="row justify-center">
+        <div class="sm:col-10 md:col-8 lg:col-6">
+          <span
+            class="text-[8rem] block font-bold text-dark dark:text-darkmode-dark"
+            >404</span
+          >
+          <h1 class="h2 mb-4">Page not found</h1>
+          <div class="content">
+            The page you are looking for might have been removed, had its name
+            changed, or is temporarily unavailable.
           </div>
+          <a
+            href="{{ site.BaseURL | relLangURL }}"
+            class="btn btn-primary mt-8">
+            Back to home
+          </a>
         </div>
       </div>
-    </section>
-  {{ end }}
+    </div>
+  </section>
 {{ end }}