wp-calypso/client/my-sites/subscribers/components/shared/popover-style.scss

.subscriber-popover__toggle {
	cursor: pointer;

	.gridicons-ellipsis {
		transition: transform 0.15s cubic-bezier(0.175, 0.885, 0.32, 1.275);
	}

	&.is-popover-visible .gridicons-ellipsis {
		transform: rotate(90deg);
	}
}