Updated CSS style of the day for product and article scroll buttons.

Updated CSS style of the day for product and article scroll buttons. Attention! If you changed the style of buttons earlier, then you need to update it. The scroll button is implemented using the CSS AFTER pseudo-element.

Added XML / YML upload for MarketPlace Rozetka and Yandex Market with product characteristics.
Added mobile version of HTML editor.
Jquery library updated → 3.7