diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index b3b3c16..3937b9c 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -1509,34 +1509,29 @@ function template_preprocess_field(&$variables, $hook) {
   // readers.
   $variables['label'] = SafeMarkup::checkPlain($element['#title']);
 
+  // Check if there are multiple field items.
+  $variables['multiple'] = FALSE;
+  if (isset($element['#items']) && is_callable($element['#items'], 'getFieldDefition') && is_callable($element['#items']->getFieldDefinition(), 'isMultiple')) {
+    $variables['multiple'] = $element['items']->getFieldDefinition()->isMultiple();
+  }
+
   static $default_attributes;
   if (!isset($default_attributes)) {
     $default_attributes = new Attribute;
   }
 
-  // Helper variables for the field template to make it easier to read.
-  // @todo this needs better documentation ;)
-  // We want to know how we want to wrap a field and when to merge in css
-  // classes, so a field dont have any divitis and is wrapped in the smallest
-  // amount possible.
-  // If theres multiple fields, and no label, then the outter wrapper should
-  // have a class attached to define that theres multiple items (.field__items)
-  // if theres multiples and the label isnt hidden and content_attributes have
-  // been set ...
-  // Do the field contains multiple items.
-  if ( count($element['#items']) > 1)  {
-    $variables['multiple_fields'] = TRUE;
-  }
-  if ( count($element['#items']) > 1 and $element['#label_display'] != 'hidden' ) {
-    $variables['multiple_items_wrapper'] = TRUE;
+  // Merge attributes when a multiple-value field has a hidden label.
+  if ($element['#label_display'] == 'hidden' && $variables['multiple']) {
+    $variables['attributes'] = NestedArray::mergeDeep($variables['attributes'], $variables['content_attributes']);
   }
-  // Check if theres multiple fields, the label is hidden and content_attributes is empty.
-  if ( count($element['#items']) > 1 and $element['#label_display'] == 'hidden' and empty($variables['content_attributes']) ) {
-    $variables['multiple_hiddenlabel_no_content_attributes'] = TRUE;
+  // Merge attributes when a single-value field has a hidden label.
+  if ($element['#label_display'] == 'hidden' && !$variables['multiple'] && is_object($element['#items'][0])) {
+    $variables['content_attributes'] = NestedArray::mergeDeep($variables['content_attributes'], (array) $element['#items'][0]->_attributes);
+    $variables['attributes'] = NestedArray::mergeDeep($variables['attributes'], $variables['content_attributes']);
   }
-  // Check if theres multiple fields or a visible label or content_attributes is not empty.
-  if ( count($element['#items']) > 1 or $element['#label_display'] != 'hidden' or !empty($variables['content_attributes']) ) {
-    $variables['multiple_visiblelabel_content_attributes'] = TRUE;
+  // Merge attributes when a single-value field has a visible label.
+  if ($element['#label_display'] != 'hidden' && !$variables['multiple'] && is_object($element['#items'][0])) {
+    $element['#items'][0]->_attributes = NestedArray::mergeDeep($variables['content_attributes'], (array) $element['#items'][0]->_attributes);
   }
 
   // We want other preprocess functions and the theme implementation to have
diff --git a/core/modules/system/templates/field.html.twig b/core/modules/system/templates/field.html.twig
index 9a1fbf4..10f21e0 100644
--- a/core/modules/system/templates/field.html.twig
+++ b/core/modules/system/templates/field.html.twig
@@ -25,7 +25,7 @@
  * - title_attributes: HTML attributes for the title.
  * - label: The label for the field.
  * - content_attributes: HTML attributes for the content.
- * - multiple_fields: Whether theres is multiple field items.
+ * - multiple: TRUE if a field can contain multiple items.
  * - items: List of all the field items. Each item contains:
  *   - attributes: List of HTML attributes for each item.
  *   - content: The field item's content.
@@ -39,34 +39,29 @@
  */
 #}
 
-{% if outerwrapper_field_items %}
-<div{{ attributes }}>
-{% elseif outerwrapper %}
-<div{{ attributes }}>
-{% endif %}
-
-  {% if not label_hidden %}
-    <div{{ title_attributes }}>{{ label }}:</div>
+{% if label_hidden %}
+  {% if multiple %}
+    <div{{ attributes }}>
+      {% for item in items %}
+        <div{{ item.attributes }}>{{ item.content }}</div>
+      {% endfor %}
+    </div>
+  {% else %}
+    {% for item in items %}
+      <div{{ attributes }}>{{ item.content }}</div>
+    {% endfor %}
   {% endif %}
-
-  {% if multiple_items_wrapper %}
+{% else %}
+  <div{{ attributes }}>
+    <div{{ title_attributes }}>{{ label }}:</div>
+    {% if multiple %}
     <div{{ content_attributes }}>
-  {% endif %}
-
-  {# Item #}
-  {% for item in items %}
-    {% if (multiple_fields or not label_hidden or item.attributes.storage is not empty ) %}
-      <div{{ item.attributes }}>{{ item.content }}</div>
-    {% else %}
-      <div{{ attributes }}>{{ item.content }}</div>
-    {% endif %}
-  {% endfor %}
-  {# /Item #}
-
-  {% if multiple_items_wrapper %}
+      {% endif %}
+      {% for item in items %}
+        <div{{ item.attributes }}>{{ item.content }}</div>
+      {% endfor %}
+      {% if multiple %}
     </div>
-  {% endif %}
-
-{% if (outerwrapper_field_items or outerwrapper) %}
-</div>
+    {% endif %}
+  </div>
 {% endif %}
diff --git a/core/themes/classy/templates/field/field.html.twig b/core/themes/classy/templates/field/field.html.twig
index 9507de9..953546f 100644
--- a/core/themes/classy/templates/field/field.html.twig
+++ b/core/themes/classy/templates/field/field.html.twig
@@ -25,7 +25,7 @@
  * - title_attributes: HTML attributes for the title.
  * - label: The label for the field.
  * - content_attributes: HTML attributes for the content.
- * - multiple_fields: Whether theres is multiple field items.
+ * - multiple: TRUE if a field can contain multiple items.
  * - items: List of all the field items. Each item contains:
  *   - attributes: List of HTML attributes for each item.
  *   - content: The field item's content.
@@ -52,41 +52,30 @@
     label_display == 'visually_hidden' ? 'visually-hidden',
   ]
 %}
-{# Test which outer wrapper is needed, depending on the field content. #}
-{# {% if (multiple_fields and label_hidden and content_attributes.storage is empty) %} #}
-  {# {% set outerwrapper_field_items = true %} #}
-{# {% elseif (multiple_fields or not label_hidden or content_attributes.storage is not empty) %} #}
-  {# {% set outerwrapper = true %} #}
-{# {% endif %} #}
 
-{% if multiple_hiddenlabel_no_content_attributes %}
-<div{{ attributes.addClass(classes).addClass('field__items') }}>
-{% elseif multiple_visiblelabel_content_attributes %}
-<div{{ attributes.addClass(classes) }}>
-{% endif %}
-
-  {% if not label_hidden %}
-    <div{{ title_attributes.addClass(title_classes) }}>{{ label }}:</div>
-  {% endif %}
-
-  {% if multiple_items_wrapper %}
-    <div{{ content_attributes.addClass('field__items') }}>
+{% if label_hidden %}
+  {% if multiple %}
+    <div{{ attributes.addClass(classes).addClass('field__items') }}>
+      {% for item in items %}
+        <div{{ item.attributes.addClass(classes).addClass('field__item') }}>{{ item.content }}</div>
+      {% endfor %}
+    </div>
+  {% else %}
+    {% for item in items %}
+      <div{{ attributes.addClass(classes).addClass('field__item') }}>{{ item.content }}</div>
+    {% endfor %}
   {% endif %}
-
-  {# Item #}
-  {% for item in items %}
-    {% if (multiple_fields or not label_hidden or item.attributes.storage is not empty ) %}
+{% else %}
+  <div{{ attributes.addClass(classes) }}>
+    <div{{ title_attributes.addClass(title_classes) }}>{{ label }}:</div>
+    {% if multiple %}
+      <div{{ content_attributes.addClass('field__items') }}>
+    {% endif %}
+    {% for item in items %}
       <div{{ item.attributes.addClass('field__item') }}>{{ item.content }}</div>
-    {% else %}
-      <div{{ attributes.addClass(classes).addClass('field__item') }}>{{ item.content }}</div>
+    {% endfor %}
+    {% if multiple %}
+      </div>
     {% endif %}
-  {% endfor %}
-  {# /Item #}
-
-  {% if multiple_items_wrapper %}
-    </div>
-  {% endif %}
-
-{% if (multiple_hiddenlabel_no_content_attributes or multiple_visiblelabel_content_attributes) %}
-</div>
+  </div>
 {% endif %}