diff --git a/honeypot.module b/honeypot.module
index 83ad301..e806ad8 100644
--- a/honeypot.module
+++ b/honeypot.module
@@ -135,7 +135,7 @@ function honeypot_add_form_protection(&$form, &$form_state, $options = array())
       '#prefix' => '<div class="honeypot-textfield">',
       '#suffix' => '</div>',
     );
-    drupal_add_css(drupal_get_path('module','honeypot') . '/css/honeypot.css', 'module'); // Hide honeypot.
+    $form['#pre_render'][] = '_honeypot_form_add_css';
   }
 
   // Build the time restriction element (if it's not disabled).
@@ -162,6 +162,17 @@ function honeypot_add_form_protection(&$form, &$form_state, $options = array())
 }
 
 /**
+ * Form pre_render callback to add CSS.
+ *
+ * Using this callback rather than adding the CSS inline helps the added CSS
+ * apply even in case of a failed form validation.
+ */
+function _honeypot_form_add_css($form) {
+  drupal_add_css(drupal_get_path('module','honeypot') . '/css/honeypot.css', 'module'); // Hide honeypot.
+  return $form;
+}
+
+/**
  * Validate honeypot field.
  */
 function _honeypot_honeypot_validate($element, &$form_state) {