add bgimage style for spring

packages/app/src/components/Theme/ThemeSpring.module.scss

@@ -25,6 +25,19 @@ $accentcolor: #e08dbc;
   border-bottom: $accentcolor 4px solid;
 }
 
+.theme :global {
+  .bg-image-wrapper {
+    position: fixed;
+    width: 100%;
+    height: 100%;
+  }
+
+  .bg-image {
+    object-fit: cover;
+    object-position: bottom;
+  }
+}
+
 //== Light Mode
 //
 .theme :global {
@@ -107,7 +120,6 @@ $accentcolor: #e08dbc;
 
   .growi:not(.login-page) {
     // add background-image
-    #page-wrapper,
     .page-editor-preview-container {
       background-image: url('/images/themes/spring/spring02.svg');
       background-attachment: fixed;