Super-simple breakpoint mixin

breakpoint.scss

// Super simple mobile-first breakpoint mixin:
@mixin breakpoint($from) {
  @media screen and (min-width: $from)  { @content; }
}

// Example usage:
$small: 480px;
nav {
  @include breakpoint($small) {
    display: none;
  }
}

// ...alternative usage (for, eg. one-off tweakpoints):
// cf. https://adactio.com/journal/6044
nav {
  @include breakpoint(480px) {
    display: none;
  }
}