Also needed to make things cleaner and properly usable whether
landscape or portrait, after changing to multiline textarea rather
than single line user input.
Avoid hardcoding the chat-till-now display area height, instead
make it a flex-growable within a flex column of ui elements within
a fixed vertical area.
Avoid browser quirk mode with DOCTYPE.
Help with accessibility a bit by specifying the language explicitly.
Specify the char encoding explicitly, inturn utf-8 is a safe bet,
even with intermixing of languages if reqd in future.
Add a cache-control http-equiv meta tag, which in all probability
will be ignored.
Defer js loading and execution, just for fun and future, not that
critical here as it stands now.