bluespec-docs/sass/_variables.scss

@mixin min-screen($min-width: $body-width) {
   @media screen and (min-width: $min-width) {
     @content;
   }
}

@mixin max-screen($max-width: $body-width) {
   @media screen and (max-width: $max-width) {
     @content;
   }
}

$sidebar-width: 300px;