The following description refers to the option "Display type" = Header 3, which is focused on the item search function.
In order to change
- the button colour in the header, please go to theme configurations and choose "Layout options > Settings"
- the frame colour, please choose "Frame colour in the Header"
- the text colour, please choose "Link Colour"
- the icons, please choose "Icon Colour"
- the button background, please choose "Background Colour Headbar".