settings.json, links appear in the order of header.links:
design.accentColor unless you explicitly set
header.button.color to a six-digit hex color. If neither color is set, it uses
#111111. Button text automatically uses black or white for contrast, including
on hover.
Setting a color in the button’s picker creates an override. Later accent changes
preserve that override. Click Use accent color in the button’s picker to
remove it and resume following the accent, or Use default color when no
accent is set. In settings.json, remove header.button.color to inherit.
An existing explicit value, including #111111, remains an override.
Set header.button to null or omit it to hide the button.
Header position
Setheader.position to "scroll" (the default) to let the header scroll with
the page, or "fixed" to keep it at the top while readers scroll.