Fixed object with flex properties

I have a nav side bar that I want to be perfectly aligned with its parent object which is in flex. I’m just curious which is the best method to making this happen. Right now it works on my screen but when I scale up to a 27" iMac I can see the dots are off by a pixel or so.

For more context, in the picture shown I want the dot to be aligned perfectly with the vertical line in every scalability situation for different devices.

Any suggestions?

Here is my public share link:

can you show me where the nav is located?.. I cant seem to find it. :confused: