Calender: add variant options

### Description

I would like variant options for the calendar (Solid, Soft, Subtle, Outline, Ghost), where currently it's just 'solid' currently. 

### Additional context

<img width="260" height="288" alt="Image" src="https://github.com/user-attachments/assets/dd5ae43c-efc1-41bf-889e-fcfcbbfda953" />
<p>e.g. Soft</p>