How to align my Diagram type Graph into center?

Hello Experts,

I have following 2 questions, could you please do guide me on same:

1st question:
Could you please do help me here, I have created diagram type graph and its left aligned in panel, I need to align it to center, how could I do it??

2nd question:
Could you please do let me know how could I increase font size of text in(boxes created by mermaid JS) graphs??

R. Singh