Sass

create-nimation.scss

@mixin create-anim($name) {
	@-moz-keyframes #{$name} { @content; };
	@-webkit-keyframes #{$name} { @content; };
	@-ms-keyframes #{$name} { @content; };
	@-o-keyframes #{$name} { @content; };
	@keyframes #{$name} { @content; };
}

set-prefixes.scss

@mixin set-prefixes($prop,$val){
	-moz-#{$prop}: #{$val};
	-webkit-#{$prop}: #{$val};
	-ms-#{$prop}: #{$val};
	-o-#{$prop}: #{$val};
	#{$prop}: #{$val};
}

using.scss

@include create-anim(dash_width) {
	from { width: $bt-width; }
	to { width: 0; }
};

@include set-prefixes(transition, all 250ms);