Please remove dividers between items

[lucaben]

Add-on version: 0.13.1
Firefox version: 101.0
OS + OS-Version: Catalina 10.15.7
Other tab + user interface related add-ons: OneTab

This is a suggestion. The horizontal lines that appear between each vertical tab make the UI look very old and heavy, and they take up space. The list is going to look much tidier and cleaner without the dividers. The highlighting of pinned tabs and selected tab can also be made more subtle, the grey background with blue dividers look very heavy. Thanks for your efforts