WP Category Widget

TWO QUERIES

1. I have used the widget inside an elementor single post template and like to change the design of the category widget. I would like to remove the outline, I would like to remove the gradient, I have tried using the selector ‘postform’ but the only css that works is for changes in the text inside and the height and colour of the widget.
2. Once I change the colour of the wigdet and publish the page, it reverts to some deflate colour of its own. I don’t understand why? Please help

The page I need help with: [log in to see the link]