Post

To disable Native Apple UI in Safari you can set the "-webkit-appearance" style to none;
-- defragmenteur

Yes, I know but the dropdown menu would not look like a dropdown anymore and you have to fake in that down triangle icon and that triangle icon will not register clicks so the dropbox would not open and than you can add javascript to prevent that, etc.
Not worth it imho just to get flatter dropdowns on Safari which might come "for free" with a next Apple update.
Anyway: "ModularGrid? Isn't that the tasteful site with the beautiful webdesign?" said no one ever ;)