Merge pull request #54 from flightaware/settings_checkboxes

Fix settings checkboxes on high dpi screens

public_html/style.css

@@ -627,6 +627,7 @@ select.error, textarea.error, input.error {
     background-image: url('images/box-empty.png');
     background-repeat: no-repeat;
     background-position: center;
+    background-size: contain;
     cursor: pointer;
 }
 
@@ -771,4 +772,4 @@ select.error, textarea.error, input.error {
     #toggle_sidebar_button.hide_sidebar {
         background-image: url("images/map-icon@3x.png");
     }
-}
+}