diff --git a/weasyprint/css/__init__.py b/weasyprint/css/__init__.py
index 43d13962c..e0e76dcbd 100644
--- a/weasyprint/css/__init__.py
+++ b/weasyprint/css/__init__.py
@@ -117,6 +117,10 @@ def __init__(self, html, sheets, presentational_hints, target_collector):
                     root=html.etree_element, parent=element,
                     base_url=html.base_url, target_collector=target_collector)
 
+        # Clear the cascaded styles, we don't need them anymore. Keep the
+        # dictionary, it is used later for page margins.
+        self._cascaded_styles.clear()
+
     def __call__(self, element, pseudo_type=None):
         style = self._computed_styles.get((element, pseudo_type))