diff --git a/classes.py b/classes.py
index df466b5..f6eec84 100644
--- a/classes.py
+++ b/classes.py
@@ -178,7 +178,7 @@ class Site:
         visible_content_items = [c for c in self.content_items if c.data.get("hidden") != True]
         for category in self.categories:
             category_index = Path(f"{self.output_dir}/categories/{category}.html")
-            category_items = [i for i in visible_content_items if category in i.data.get("categories")]
+            category_items = [i for i in visible_content_items if category in i.data.get("categories", "default")]
             with (category_index).open(mode="w", encoding="utf-8") as f:
                 f.write(config.index_template.render(page_title=f"{config.site_name}: [ {category} ]", content_items=category_items, categories = self.categories, parent_path = '../', footer_data = footer_data))
 
diff --git a/requirements.txt b/requirements.txt
index d0d8a2c..b08b7f3 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,5 @@
 argparse
+bs4
 python-frontmatter
 jinja2
 markdown