nesting parent-selector modifiers

parent-selector-modifiers

/* instead of this */
.mobile {
	.my-module {
		color: red;
	}
}
.desktop {
	.my-module {
		color: blue;
	}
}

/* do this */

.my-module {
	.mobile & {
		color: red;
	}
	.desktop & {
		color: blue;
	}
}