Max Mega Menu - Less Spacing between Menu Columns

Hi Tom/Leo/Fellow GP Lovers,

Would anyone with experience in Mega Menus mind suggesting please, some CSS to reduce the space between menu columns? ie, I currently have 3 columns showing [in clothing], I need 4, but there's simply too much space between the columns for it to change. [I've adjusted in the Mega Menu settings, but the default spacing won't let it change.]

I've been working on it for a while - but if I just keep digging, I'll likely hit oil! I took something Tom suggested on this forum a little while back as a starting point....I'm likely on the completely wrong bus.....

.mega-stuck #mega-menu-primary {
width: 100% !important;
max-width: 100% !important;
margin-left: 5px !important;
margin-right: 5px !important;
columns: 25% !important;
}

Any suggestions please?

Thank you,
Robert