New Feature: Themes

[Lysk673]

Summary:
A feature that allows users to use a variety of different colour modes, like various high-contrast modes for people who have vision issues, etc.

Ideas:

1. Maybe a Switch with 🌙and☀️, and clicking on it can turn the website dark.
2. A wide dropdown with these types of modes:
   
3. Same as 2, a short dropdown, with text, such as 'aquatic', 'light grey', etc.

Please note, this issue is just a suggestion, and it depends on whether the owner decides to make that happen.

Thanks.