style: change navbar css so that links wrap in header
style: change navbar css so that links wrap in header

See FS#56472 for details about the header bar links displayed
incorrectly on small displays. The same patch has been applied to
Archweb.

https://bugs.archlinux.org/task/56472

jelly/arch-security-tracker,archlinux/arch-security-tracker,anthraxx/arch-security-tracker,anthraxx/arch-security-tracker,jelly/arch-security-tracker,archlinux/arch-security-tracker,anthraxx/arch-security-tracker