Adjustments in Practis child theme

I’m looking to make some changes in the design of my site medibali.com but am not able to do so. I have changed the color of the menu bar by uploading the new image file but there are some green vertical lines there, how can I change the color of those? I also would like to know how to change the color of:

The titles of the widgest
The green lines under these titles
The shadow color in the title area of these widgets
The color of the text in the widgets in the content area

I have tired using the design features but I guess these are fixed? I will really appreciate any help.

Federico