Feature Request: Support for Flexible Font Weights (100 - 900) in Syntax Highlighting (and more css-properties)

[Please excuse me if I'm in the wrong place or am doing anything else wrong - I'm rather new to this...]

I guess it won't be easy, but I really would appreciate the possibility to add font weights other than bold in syntax highlighting (and other theming-contexts as well).

Like most other developers I spent countless hours in front of my code, and having good typography is a lot more than just 'eye-candy'....

Luckily there are a lot of great developer friendly fonts to have nowadays and a lot of them come in various weights - some even variable. Syntax highlighting is a great boost to productivity, and being able to convey information that way is important.
For ergonomic reasons however I find it hard to work with too bright colors and when using less saturated colors it is often problematic to find a good balance, as yellow(ish) colors almost ever shine very bright, while (darker) reds for example tend to look very 'thin'.

I would really like to have the option to use font-weight 200 for yellows and 300 for reds for example.

Also support for 'oblique' in addition to 'italic' would be great and other typographic css features too.
I guess that TextMate-Syntax is a hard limiting factor, but maybe semantic highlighting could offer more of a choice?

Thank You!

BTW.: I do very much appreciate what you are giving us with VS-Code and would like to generally tank everyone working on that project!

The issue names no files or tests; start by investigating the TextMate-Syntax and semantic highlighting entry points mentioned in the request. Determine whether font weights from 100 to 900, oblique styling, and related CSS properties can be represented, and define the supported behavior before implementation.