Responsive Breakpoint Mixin
@mixin breakpoint($point) {
@if $point == large {
@media (min-width: 64.375em) { @content; }
}
@else if $point == medium {
@media (min-width: 50em) { @content; }
}
@else if $point == small {
@media (min-width: 37.5em) { @content; }
}
}