diff --git a/src/pyj/book_list/cover_grid.pyj b/src/pyj/book_list/cover_grid.pyj
index de8b21516f..bfc61001f9 100644
--- a/src/pyj/book_list/cover_grid.pyj
+++ b/src/pyj/book_list/cover_grid.pyj
@@ -25,7 +25,7 @@ def cover_grid_css():
         sel, margin=f'{margin}{margin_unit}', display='flex', align_content='flex-end', align_items='flex-end', justify_content='space-around',
         max_width=THUMBNAIL_MAX_WIDTH+'px', max_height=THUMBNAIL_MAX_HEIGHT+'px', cursor='pointer',
         min_width=f'{THUMBNAIL_MAX_WIDTH // 2}px', min_height=f'{THUMBNAIL_MAX_HEIGHT // 2}px')
-    mq =  '@media all and (orientation: {orient}) {{ {sel} {{ width: 21{dim}; height: 28{dim} }} }}'
+    mq =  '@media all and (orientation: {orient}) {{ {sel} {{ width: 21{dim}; height: 28{dim} }} }}\n'
     for dim in 'vw', 'vh':
         ans += mq.format(sel=sel, dim=dim, orient='portrait' if dim is 'vw' else 'landscape')
     ans += build_rule(f'{sel}:hover', transform='scale(1.2)')