@mixin max-width($breakpoint) {
    @if map-has-key($breakpoints, $breakpoint) {
        @media (max-width: map-get($breakpoints, $breakpoint)) {
            @content;
        }
    }
}

@mixin min-width($breakpoint) {
    @if map-has-key($breakpoints, $breakpoint) {
        @media (min-width: map-get($breakpoints, $breakpoint)) {
            @content;
        }
    }
}