diff --git a/core/modules/system/css/system.admin.css b/core/modules/system/css/system.admin.css
index b62d3ad..b2db9a0 100644
--- a/core/modules/system/css/system.admin.css
+++ b/core/modules/system/css/system.admin.css
@@ -222,21 +222,6 @@ small .admin-link:after {
 }
 
 /**
- * Theme settings.
- */
-.theme-settings-left {
-  float: left;
-  width: 49%;
-}
-.theme-settings-right {
-  float: right;
-  width: 49%;
-}
-.theme-settings-bottom {
-  clear: both;
-}
-
-/**
  * Appearance page.
  */
 .theme-info__header {
diff --git a/core/modules/system/src/Form/ThemeSettingsForm.php b/core/modules/system/src/Form/ThemeSettingsForm.php
index 25568b0..44649d2 100644
--- a/core/modules/system/src/Form/ThemeSettingsForm.php
+++ b/core/modules/system/src/Form/ThemeSettingsForm.php
@@ -147,7 +147,6 @@ public function buildForm(array $form, FormStateInterface $form_state, $theme =
         '#type' => 'details',
         '#title' => t('Logo image settings'),
         '#open' => TRUE,
-        '#attributes' => array('class' => array('theme-settings-bottom')),
         '#states' => array(
           // Hide the logo image settings fieldset when logo display is disabled.
           'invisible' => array(