Add custom 404 page

Author: pmichaillat

assets/css/common/404.css

@@ -0,0 +1,13 @@
+.not-found {
+    position: absolute;
+    top: 0; left: 0; right: 0; bottom: 0;
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    justify-content: center;
+    font-size: 1.3rem;
+    font-weight: 500;
+    text-align: center;
+    color: var(--secondary);  
+    gap: 2.5rem;
+}

layouts/404.html

@@ -0,0 +1,7 @@
+{{ define "title" }}404{{ end }}
+{{ define "main" }}
+  <div class="not-found">
+    <h1>Page not found</h1>
+    <p>Sorry, the requested page could not be found.</p>
+  </div>
+{{ end }}

layouts/partials/head.html

@@ -8,7 +8,15 @@
 {{- end }}
 
 {{- /* Title */}}
-<title>{{ if .IsHome }}{{ else }}{{ if .Title }}{{ .Title }} | {{ end }}{{ end }}{{ site.Title }}</title>
+<title>
+  {{- if eq .Kind "404" -}}
+    404: Page not found | {{ .Site.Title }}
+  {{- else if and (not .IsHome) .Title -}}
+    {{ .Title }} | {{ .Site.Title }}
+  {{- else -}}
+    {{ .Site.Title }}
+  {{- end -}}
+</title>
 
 {{- /* Meta */}}
 {{- if .IsHome }}