Twenty Fifteen theme navigation menu resize and title font option

Hi I have two questions in regarding the Twenty Fifteen theme, can you please help:
1. How can i resize the vertical navigation menu bar?
2. How can I change the site title font and size?
3. How can I make the vertical navigation menu bar stay fix?
4. How can I move the page title up screen of the page?

You guys are awesome and thanks again for all your help.