Dark mode map gradient visibility

Created by: acorreya

Describe the bug Map gradient color scheme needs to be tweaked in main page while using dark mode for visibility of low count states.

To Reproduce Steps to reproduce the behavior:

1. Go to 'index'
2. Scroll down to 'india map'
3. See error

Expected behavior Better visibility for states like Goa.

Screenshots

Smartphone (please complete the following information):

• Device: Mi A3
• OS: Android 10 stock/pure
• Browser Firefox
• Version 68.7.0