Fixed default home page menu text color

[jsorohova]

Problem:
Default home page menu text color is black which is not visible on the dark blue banner.

Solution:
Change text color to white.

[github-actions]

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This scan used axe-core 4.3.2 with Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/86.0.4240.75 Safari/537.36.