Zukitwo-cupertino theme is related to great zukitwo theme, Author mention about aim of this theme is to make Gnome-Shell looks better like Gtk theme(Adwaita Cupertino). This theme perfectly works with all resolutions bigger screens or you can use this with smaller screen.
Check icons collection
You can use Unity Tweak Tool, Gnome-tweak-tool or Ubuntu-Tweak to change themes.
To install Zukitwo Cupertino theme on Ubuntu/Mint open Terminal (Press Ctrl+Alt+T) and copy the following commands in the Terminal:
Source: Zukitwo Cupertino