How to target language specific elements with custom themes

[Jarvismkennedy]

I have recently moved from vscode to helix, and I would like the themes to match more closely to what I am used to in vscode. The Dracula theme that comes out of the box with helix is not quite what I am looking for. I am mostly developing in javascript, so I would like to change the color of variables based on if they are declared with "const", "let", or if they reference a function, and I would also like to target JSX elements. How would I target these things in my custom theme.toml ? I have tried targeting these by referencing the docs but haven't been able to figure it out yet.

For reference, this is what It looks like in vscode with the dracula theme.