Colors in portal dark theme layer list don't quite fit after update

[iannesbitt]

Describe the bug The dark theme needs to be refreshed after the updates to the light theme from 2.28.0. Dark theme colors are sometimes too dark to distinguish from the background.

To Reproduce Steps to reproduce the behavior:

1. Go to https://drp.dataone.org/portals/drp-data
2. Look at layer list
3. See issue

Expected behavior Theme colors should be readable.

Screenshots

Desktop (please complete the following information):

• OS: all
• Browser: all
• Version: all

Smartphone (please complete the following information):

• Device: all
• OS: all
• Browser: all
• Version: all

Additional context n/a

[robyngit]

Notes about implementing a more robust color theme system for portals: https://docs.google.com/document/d/1Eb0uixayVeEgO0AcIEjDO6J5555A_CA1BK0nZp1s-uk/edit#heading=h.f99d70q8f3z0