apply bgimage style for wood

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

@@ -14,7 +14,6 @@
 
 .growi:not(.login-page) {
   // add background-image
-  #page-wrapper,
   .page-editor-preview-container {
     background-image: url('/images/themes/wood/wood.jpg');
     background-attachment: fixed;
@@ -35,6 +34,23 @@
 $themecolor: #b9b177;
 $themelight: #f5f3ee;
 
+.theme :global {
+  .wrapper {
+    position: relative;
+  }
+
+  .bg-image-wrapper {
+    position: fixed;
+    width: 100%;
+    height: 100%;
+  }
+
+  .bg-image {
+    object-fit: cover;
+    object-position: center center;
+  }
+}
+
 //== Light Mode
 //
 .theme :global {