Rated 4 out of 5 stars

Can we get options for textshadows? Also, adding a tabs on bottom option that looks fine with Vivaldi would be great. The current remaining option/add-on working in 57 only uses an ugly version with a blue line on top of the selected tab.

This review is for a previous version of the add-on (1.4.1). 

Thanks for the review! The beta version is now a WebExtension: https://addons.mozilla.org/en-US/firefox/addon/vivaldifox/versions/beta

Unfortunately, text shadows can't be configured with WebExtensions. As for the other issues, I encourage you to check the options available in the beta version, it's more fine-grained than 3 months ago :)