How do I modify the QListView to get rid of the frames around the arrow buttons?

Hello. I am using theQListView. In order for it to match the style of our user interface we would like to for the arrow buttons and the slider to not have a frame around them. I will attach examples of what we have and what we want. I am not very experienced with Qt. Any suggestions will be very much appreciated.

We are using Qt 5.5.1, Ubuntu 16.04 64-bit, running on ARMv8.
I am attaching another file: ui_videolistscreen.h.