move sass style

src/client/styles/scss/theme/_apply-colors-dark.scss

@@ -343,6 +343,12 @@ body.on-edit {
   }
 }
 
+.growi .main {
+  .page-comments-row {
+    background: $bgcolor-subnav;
+  }
+}
+
 /*
  * GROWI tags
  */
@@ -363,12 +369,3 @@ body.on-edit {
     }
   }
 }
-
-/*
- * GROWI comment form
- */
-.growi .main {
-  .page-comments-row {
-    background: darken($gray-900, 5%);
-  }
-}

src/client/styles/scss/theme/_apply-colors-light.scss

@@ -273,6 +273,12 @@ $table-hover-bg: $bgcolor-table-hover;
   }
 }
 
+.growi .main {
+  .page-comments-row {
+    background: $bgcolor-subnav;
+  }
+}
+
 /*
  * GROWI tags
  */
@@ -293,12 +299,3 @@ $table-hover-bg: $bgcolor-table-hover;
     }
   }
 }
-
-/*
- * GROWI comment form
- */
-.growi .main {
-  .page-comments-row {
-    background: lighten($gray-100, 3%);
-  }
-}