This introduces another breakpoint below 'small' screen as defaulted in foundation

foundation-smaller-breakpoint.scss

// foundation_and_overrides.scss

$xsmall-screen: 400px;
$small-screen: 768px;
$medium-screen: 1280px;
$large-screen: 1440px;

// media query + column override

@media (max-width: #{$xsmall-screen}) {
  .column, .columns {
    width: 100%;
    padding: 0;
  }
}