How to change color of button in canvas

The first image is the color of my button (I think it is yellow by default). I want it to look more like the second image below, ignore the text. does anyone have an idea for what the code would look like?
my code kinda looks like this, foir the button atleast

stack_box_slot:
Widget := Button
HorizontalAlignment := horizontal_alignment.Fill
Distribution := option{10.0}

image

image2