Skipping over pseudo contexts has fixed most of the tests.

src/renderer/parameters_context.rs

@@ -103,6 +103,10 @@ impl Walkable for ParametersContext {
             OwnedRValue::RVLiteral(literal) => Ok(literal),
         }
     }
+
+    fn is_pseudo_element(&self) -> bool {
+        true
+    }
 }
 
 impl Clone for ParametersContext {