How can I impact the width of the columns?

[sandrooco]

First of all, thank you for this library!
I got it working quite well, have a question about responsive though:
I want the grid to show only one column with 100% width on mobiles, 50% + gutter on tablets and 33% + gutter on desktops. So I don't have a fixed baseWidth. What approach would you use for this?

Also, I saw that there is a certain responsiveness but so far couldn't make out the pattern that is used.