Change text size, frame size and banner color

Hi I like your theme a lot. I’m actually new to WP and I hope that you guys can help me with the following questions. Thank you very much!

1) anyway to change the font size of to smaller?
2) is there a way to change the frame size? I mean the slider and the grid. I would like to make them smaller. I searched previous posts–it seems it’s a complex change?
3) the banner is black and I wish I could changed it to orange. I tried to change the #0000 in the “edit” but didn’t work.

Look forward to hearing your suggestions. Thanks a lot!