Dark mode: Country flags invisible (black-on-dark) in currency selection setup

[sathwikhbhat]

Description:
During the initial account setup, on the "Choose your default currency" screen, the country flags (e.g., US, EU, GB) appear black/dark and blend into the dark mode background, making them hard to distinguish. This affects usability and accessibility (low contrast).

Expected:
Flags should adapt with higher contrast in dark mode (e.g., lighter/inverted versions or CSS filters).

Steps to Reproduce:

1. Sign up for a new account in the Paisa web UI.
2. Proceed to the "Choose your default currency" setup page.
3. Ensure dark mode is enabled (via system preference or app toggle).
4. Observe that the country flags (e.g., US, EU, GB) are hardly visible due to black-on-dark contrast.