How to match background colour right of the left seperators

[aneeshsunganahalli]

I'm a little new to this, but I'm not able to figure out why this isn't working but I wanted the background on the right of the left seperators to match so it look continuous, but not able to.

Wanted it to look like this:

Would really appreciate it if someone could help out.

[aneeshsunganahalli]

@kjnsn Would appreciate your help, cuz I couldn't find anything related to this.