Add custom 404 not found page

error page for 404 is available at /404.html

Author: ksuess

docs/_templates/404.html

@@ -0,0 +1,19 @@
+{% extends "!page.html" %}
+
+{%- block htmltitle %}
+<title>{{ title|striptags|e }}{%- for parent in parents %} – {{ parent.title }}{%- endfor %}{{ titlesuffix }}</title>
+{%- endblock %}
+
+{% block body %}
+<div>
+    <h1>Page not found</h1>
+    <p>Unfortunately we couldn't find the content you were looking for.</p>
+</div>
+
+<style>
+    /* Hide empty sub menu. */
+    .sticky-top .bd-toc {
+        visibility: hidden;
+    }
+</style>
+{% endblock %}

docs/conf.py

@@ -55,6 +55,7 @@
     "sphinxext.opengraph",
     "sphinx.ext.viewcode",  # plone.api
     "sphinx.ext.autosummary",  # plone.api
+    "notfound.extension",
 ]
 
 
@@ -206,6 +207,12 @@
 copybutton_prompt_is_regexp = True
 
 
+# -- sphinx-notfound-page configuration ----------------------------------
+
+notfound_urls_prefix = None
+notfound_template = "404.html"
+
+
 # -- Options for HTML output -------------------------------------------------
 
 # The theme to use for HTML and HTML Help pages.  See the documentation for

requirements.txt

@@ -14,3 +14,4 @@ sphinx-togglebutton
 sphinxcontrib.httpdomain  # plone.restapi
 sphinxcontrib.httpexample  # plone.restapi
 sphinxext-opengraph
+sphinx-notfound-page