Nav bar on Sydney them?

Hey guys!
So I am just messing around with the Sydney theme.
The navigation menu is ok, but I would like to edit some things.

1. I would like a light black bar with transparent opacity so people can see the nav menu ontop of the background images that I select. The bar will turn dark as soon as someone starts to scroll, but I want it to start dark enough people can see the menu items, then maybe get darker as they scroll.

2. The font size is terribly small did I miss something on how to make them bigger?

Extra Credit- If I drop a “logo image” it makes it REALLY small. I want it to line up with the nav menu and be MUCH bigger.
I dont know if this link works, but I am using the random domain https://200.2d2.myftpupload.com/ until I am built up enough to go live. Thanks for any help guys I truly appreciate it!

I might just need to pick different images for the slider huh, something like the first image (orange sunset) that is pretty uniform in color? because the float in text is hard to read on some images as well especially the Machu Pichu image. I left the images up and I will add the .pmg logo I was speaking about, (just text for now)