When tracking `Theme parsing error: gtk-buttons.css:159:10: Expected valid border` error
and looked inside `/usr/share/themes/Lubuntu-desktop/gtk-3.0/gtk-buttons.css` at 159 line, and there was:
padding: -1 2
I believe that `-1` is invalid value and should be replaced.
When tracking `Theme parsing error: gtk-buttons. css:159: 10: Expected valid border` error
and looked inside `/usr/share/ themes/ Lubuntu- desktop/ gtk-3.0/ gtk-buttons. css` at 159 line, and there was:
padding: -1 2
I believe that `-1` is invalid value and should be replaced.