How to change the colour of the Manage Profile icon (mobile view) from white to black

Summary:

In order for our company logo to remain visible on the External Career site when using mobile devices we have changed the header background colour from black to white using Custom CSS. We now have the issue where the Manage Profile icon is showing in white and therefore becomes invisible on the white header. Oracle have confirmed the icon requires custom css to change the colour - Has anyone successfully managed to change the Manage Profile icon colour this way?

Content (required):

The colour of Manage Profile is based on the Theme colour, for more configurability custom CSS should be used