“Mobile first” CSS and getting LESS to help with legacy IE

320up.less

.320up(){

.three20 {
	color: #fff;
}

} /* end 320up mixin */

base.less

.base {
	color: #000;
}

ie.less

@import "subs/base.less";
@import "subs/320.less";
.320up();

style.less

@import "subs/base.less";
@import "subs/320.less";
@media (min-width:320px) {
	.320up();
}