Fixed broken CSS on 404 page, closes #777

datasette/app.py

@@ -1015,7 +1015,16 @@ class DatasetteRouter(AsgiRouter):
         templates = ["500.html"]
         if status != 500:
             templates = ["{}.html".format(status)] + templates
-        info.update({"ok": False, "error": message, "status": status, "title": title})
+        info.update(
+            {
+                "ok": False,
+                "error": message,
+                "status": status,
+                "title": title,
+                "base_url": self.ds.config("base_url"),
+                "app_css_hash": self.ds.app_css_hash(),
+            }
+        )
         headers = {}
         if self.ds.cors:
             headers["Access-Control-Allow-Origin"] = "*"

tests/test_html.py

@@ -965,6 +965,18 @@ def inner_html(soup):
     return inner_html.strip()
 
 
+@pytest.mark.parametrize("path", ["/404", "/fixtures/404"])
+def test_404(app_client, path):
+    response = app_client.get(path)
+    assert 404 == response.status
+    assert (
+        '<link rel="stylesheet" href="/-/static/app.css?{}'.format(
+            app_client.ds.app_css_hash()
+        )
+        in response.text
+    )
+
+
 @pytest.mark.parametrize(
     "path,expected_redirect",
     [("/fixtures/", "/fixtures"), ("/fixtures/simple_view/", "/fixtures/simple_view")],