Support Required on Responsive Theme

Hello All,

I just started working on my wordpress website, I started with “Responsive” theme. Being a novice in this, I would like to seek support on few things:

1. What can be best free theme for a small business (class room training on some software), to have jobs also advertised on the website? Is “Responsive” good enough or there is some better than this for the said purpose?

2. Can we change the Font size of the “Call to Action” button and other headings? If YES, can someone please advise, how to go about…require a bit detailed guidance.

3. Is the size of different widgets adjustable? How can we do that?

4. How to change the color of the submenus?

5. If someone can please advise how to change different font sizes, sidebar sizes, colors…meaning to customize?

Many thanks as I look for the required support.

BR//
Asim Awan