The "Quantity Query" Mixin
You can style an element based on how many siblings it has (e.g., "if there are 4 items, make them (25%) width; if there are 3, make them 33%").
SCSS
@mixin at-least($count) {
&:nth-last-child(n + #{$count}),
&:nth-last-child(n + #{$count}) ~ & {
@content;
}
}
.menu-item {
@include at-least(4) { width: 25%; }
}