keeweb/app/styles/themes/_terminal.scss

$themes: map-merge(
    $themes,
    (
        te:
            map-merge(
                $theme-defaults,
                (
                    background-color: #222,
                    medium-color: #999,
                    text-color: #eee,
                    action-color: #13a453,
                    error-color: #c34034
                )
            )
    )
);