A fork from the vertex theme with a touch of KDE's breeze.

The original Vertex theme: https://github.com/horst3180/vertex-theme

The KDE folks: https://github.com/KDE

firefox-hide-caption-titlebar-plus: https://github.com/Javier-DarthPalpatine/firefox-hide-caption-titlebar-plus

Download the files and move the Vertex-Breeze folder to ~/.themes or do this:

cd ~/.themes
git clone https://gitlab.com/RaitaroH/Vertex-Breeze-Metacity.git
mv Vertex-Breeze-Metacity/Vertex-Breeze/ ~/.themes/

You can also move the chrome folder to your firefox profile IF you are using the firefox-hide-caption-titlebar-plus addon.

Now simply change the metacity theme from your desktops' settings.

Here is the at full length focused and unfocused. I provide minimize, maximize, unmaximize, close, menu, shade, stick/unstick buttons with focused, unfocused, pressed and hover variations.

Hover and unmaximize: