Hi Alex,
You need the full path to susy to get it to work! In the style.scss for the theme. It will be installed in the node_modules folder.
@import "normalize";
@import "/Applications/MAMP/htdocs/omeka-s/themes/default/node_modules/susy/sass/susy";
@import "base";
@media screen {
@import "screen";
}
@media screen and (min-width:800px) {
@import "desktop";
}
Cheers,
Andre