Demo user preference

[fellyph]

Hi @gagan0123, This pull request is on draft; I have a few items that I want to check:

• I will include status messages on the preference page, same as the analytics page
• I'm loading the preferences on domain C; when the page is fetching, I have a tiny blink between dark and light mode. Can I add a loader for it?
• Some JavaScript files are using (function(){}()), and some are using DOMContentLoaded. Should we define a standard to load and execute JavaScript?

Homepage

Light Mode

Dark Mode

[gagan0123]

• I will include status messages on the preference page, same as the analytics page

How will that status message look like?

• I'm loading the preferences on domain C; when the page is fetching, I have a tiny blink between dark and light mode. Can I add a loader for it?

Loader will work, but keep it simple, as soon as the iframe is loaded, remove that loader. We can also add dns-prefetch for the iframe domain in the parent, so that at least the DNS query does not take long.

• Some JavaScript files are using (function(){}()), and some are using DOMContentLoaded. Should we define a standard to load and execute JavaScript?

We can keep that for later, as having the demo ready has more priority than refactoring the code.