diff --git a/modules/past_db/past_db.css b/modules/past_db/past_db.css
index 7de8d52..805f423 100644
--- a/modules/past_db/past_db.css
+++ b/modules/past_db/past_db.css
@@ -16,6 +16,13 @@
 }
 
 /**
+ * Argument output.
+ */
+.past-argument-indented {
+  padding-left: 20px;
+}
+
+/**
  * Past severity.
  */
 table.past-severity-colors tr {
diff --git a/modules/past_db/src/Entity/PastEvent.php b/modules/past_db/src/Entity/PastEvent.php
index 054d81a..90f8386 100644
--- a/modules/past_db/src/Entity/PastEvent.php
+++ b/modules/past_db/src/Entity/PastEvent.php
@@ -9,6 +9,7 @@ namespace Drupal\past_db\Entity;
 
 use Drupal\Component\Utility\Html;
 use Drupal\Component\Utility\Unicode;
+use Drupal\Component\Render\FormattableMarkup;
 use Drupal\Core\Cache\Cache;
 use Drupal\Core\Database\Database;
 use Drupal\Core\Entity\ContentEntityBase;
@@ -591,22 +592,15 @@ class PastEvent extends ContentEntityBase implements PastEventInterface {
    *   A HTML div describing the argument and its data.
    */
   public function formatArgument($name, PastEventArgumentInterface $argument) {
-    $back = '';
-    $data = $argument->getData();
-    $indentation = [
-      '#theme' => 'indentation',
-      '#size' => 1,
+    $element = [
+      '#type' => 'details',
+      '#title' => new FormattableMarkup('@name (<em>@type</em>)', ['@name' => $name, '@type' => gettype($argument->getData())]),
+      '#open' => TRUE,
+      '#tree' => TRUE,
+      '#weight' => 10,
     ];
-    if (is_array($data) || is_object($data)) {
-      foreach ($data as $k => $v) {
-        $back .= '<div>' . \Drupal::service('renderer')->render($indentation) . '[<strong>' . Html::escape($k) . '</strong>] (<em>' . gettype($v) . '</em>): ' . $this->parseObject($v) . '</div>';
-      }
-    }
-    else {
-      $back = nl2br(Html::escape($data));
-    }
-    $back = '<div><strong>' . Html::escape($name) . '</strong> (<em>' . gettype($data) . '</em>): ' . $back . '</div>';
-    return $back;
+    $element['value'] = ['#markup' => $this->parseObject($argument->getData())];
+    return $element;
   }
 
   /**
@@ -631,7 +625,7 @@ class PastEvent extends ContentEntityBase implements PastEventInterface {
     }
 
     $back = '';
-    $css = 'style="padding-left:' . ($recursive + 10) . 'px;"';
+    $css = $recursive ? 'class="past-argument-indented"' : '';
     foreach ($obj as $k => $v) {
       $back .= '<div ' . $css . ' >[<strong>' . Html::escape($k) . '</strong>] (<em>' . gettype($v) . '</em>): ' . $this->parseObject($v, $recursive + 1) . '</div>';
     }
diff --git a/modules/past_db/src/PastEventViewBuilder.php b/modules/past_db/src/PastEventViewBuilder.php
index b2f565a..a60a039 100644
--- a/modules/past_db/src/PastEventViewBuilder.php
+++ b/modules/past_db/src/PastEventViewBuilder.php
@@ -45,17 +45,7 @@ class PastEventViewBuilder extends EntityViewBuilder {
 
       // @todo Display as vertical_tabs if that is enabled outside forms.
       foreach ($entity->getArguments() as $key => $argument) {
-        $build[$id]['fieldset_' . $key] = array(
-          '#type' => 'details',
-          '#title' => ucfirst($key),
-          '#open' => TRUE,
-          '#tree' => TRUE,
-          '#weight' => 10,
-        );
-        $build[$id]['fieldset_' . $key]['argument_' . $key] = array(
-          '#type' => 'item',
-          '#markup' => $entity->formatArgument($key, $argument),
-        );
+        $build[$id]['fieldset_' . $key] = $entity->formatArgument($key, $argument);
       }
 
     }