Set the data-section-theme value to one of your 10 color themes. Leave this off to match the current header styles.
<SecondaryNav
data-section-theme="light 1"
>
... Your Nav Items Here
</SecondaryNav>
Here are your options:
light 1
light 2
lightest 1
lightest 2
bright 1
bright 2
dark 1
dark 2
darkest 1
darkest 2