fix hufflepuff

packages/preset-themes/src/styles/hufflepuff.scss

@@ -113,6 +113,9 @@
 
   &, body {
     background-image: url('../images/hufflepuff/badger-light3.png');
+    background-attachment: fixed;
+    background-position: bottom;
+    background-size: cover;
   }
 
   // Button
@@ -280,6 +283,9 @@
 
   &, body {
     background-image: url('../images/hufflepuff/badger-dark.jpg');
+    background-attachment: fixed;
+    background-position: bottom;
+    background-size: cover;
   }
 
   // Navs