How to change the color of the text, and icons/buttons in the banner frame?
In Jakarta, there is not a supported way to change that color as you want. However, a user can try the following:
1- Go to System UI > Themes.
2- Select an existing theme such as Black and White (or click the button New to create a new theme)
3- Add the code below into the field CSS:
4- Save the record.
5- Witch your instance to the theme Black and White (or to the new theme created).
6- The color may be applied to the text and buttons/icons from the banner frame.
Jakarta, Kingston, London
Check out this doc about Customizing instance appearance