Additional variables needed for Shadows, line-height, and letter spacing

Describe the Problem

Variables for these are missing:

❌ Shadows (multi-value compound property, not yet supported)
❌ Font weights as named tokens
❌ Line heights as named tokens
❌ Letter spacing as named tokens

Propose a Solution

Add them. Especially helpful for typography elements. Right now the only way to effect them is via custom CSS which is not really the vibe that Atomic is trying to go for here with building genuine Design Systems rather than patching together Variables here and Custom CSS there.

Additional Context

_No response_

Agreement

• I confirm I have read and followed all the guidelines and instructions outlined in the Feature Request form.
• I agree that my discussion may be closed without further action if it doesn't meet all the requirements outlined in the Feature Request form.