Support for GTK.Notebook?

[TomJansen]

Thank you for this theme! I have an issue however with LibreOffice. In LibreOffice, the tab bar (GTK.Notebook) looks not so pretty with WhiteSur:

Maybe we can take inspiration from the GTK.Notebook style from Adwaita? I made a small mockup using GTK_DEBUG=interactive:

This image is with the WhiteSur-Light-solid and with these CSS styles on top:

headerbar {
    border: 0px;
}

button:checked {
   background-color: #e9e9e9;
   border: 0px;
}

notebook > header.top {
    box-shadow: inset 0 0px #dcdfe3;
    background-color: white;
    border: 0px
}

notebook > header > tabs > tab {
    padding: 2px 10px;
    min-width: 20px;
    min-height: 26px;
    outline-offset: -4px;
    border: 0px solid transparent;
    border: none;
    border-radius: 0px 0px 0 0;
}

notebook > header > tabs > tab:hover:not(:checked) {
    border-bottom: 3px solid;
    border-color: #eeeeee;
}

notebook > header > tabs > tab:selected {
    border-bottom: 3px solid;
    border-color: #0860f2;
}

Note also the lighter button colors

[vinceliuice]

That will change all gtk app style

[vinceliuice]

I update it

[TomJansen]

Looks super good!