I've seen a few posts around the internet of people modifying the panels to have rounded corners, transparency, different colors, etc... Where do I go in my files to make these modifications?

This is done with GTK themes; there's tons of them out there. Some of them are even in the Solus repo. 🙂

Once installing a theme you want to try, open Budgie Desktop Settings and select it with the Widgets dropdown to switch to that theme.

If you navigate to ~/.config/gtk-3.0/gtk.css and open gtk.css you can change the transparency levels of your Budgie Panels.

I don't recall if I had to create this file or not. The only thing in the file is the following:

.budgie-panel {
background-image: none;
background-color: rgba(0,0,0,0.50);
}

If you are not familiar with the RGB code the last number 0.50 is the transparency effect level. 0.0 would be fully transparent and 1.0 would be fully opaque.

As far as I know there are no GUI applications or themes available that can do this. You have to manually edit the css file. It isn't hard at all though.

It has been well over a year since I did this but I recall either having to logout and log back in to make the transparency effects stick or reboot the computer.

    jrsilvey As far as I know there are no GUI applications or themes available that can do this.

    There are absolutely GTK themes that do this; Materia is one, and is in the repo. Maybe also double-check the panel transparency setting in Budgie Desktop Settings > _ Panel > Settings > Transparency.

      wingman-4 Unless they provide up-to-date Budgie-specific theming, no they're not going to be Budgie friendly. Most are just forks of other themes which have had out-of-date Budgie support for a long time now.

          I just checked out multiple themes with Budgie Desktop Settings transparency. You can either have always, dynamic, or none. You can't set the specific transparency level you want. It is dependant upon the theme.

          I deleted the gtk.css file I described earlier, logged out, and changed my theme to Plata Noir and the transparency to Always (I switched the picture here to Dynamic before I took the screenshot on accident).

          This is the result.

          This is how the Plata Noir theme looks with None picked for transparency.

          This image is of the Plata Noir theme with the GTK.css file added back and transparency set to 75%.

          This is what the transparency looks like at 50% with the Matcha-Dark-Sea theme.

          Budgie Desktop Settings allows you to have an always on or always off transparency setting. Dynamic only works in a few cases that I have seen, depending on what windows are open.. I am not very familiar with how it functions nor do I understand how it is supposed to.

          However if you want to customize the Budgie Desktop and choose which color and transparency level you want for the Budgie Panel regardless of which theme you are using like the original poster wanted..

          You need to change the gtk.css located in /.config/gtk-3.0 like my initial post described.

            jrsilvey Dynamic only works in a few cases that I have seen, depending on what windows are open.. I am not very familiar with how it functions nor do I understand how it is supposed to.

            Dynamic means that the panel will be transparent if there is no full-screen window up. If there is a full-screen window open, then the panel will not be transparent.

              Big thanks to all the responses, this gives me something to tinker with

              13 days later

              JoshStrobl The biggest problem I see with 3rd party themes after a few years of experimenting on Budgie is that raven panel doesn't display properly when opened and transparency on themes not intended for Budgie doesn't work . I would amend my post and say some are Budgie friendly. The quality varies , but there are dedicated theme makers that like feedback from users and work to make their products better.