Андрей Б.

&.active {
        &__lines {
          ...
        }
    }

<button class="button active">1</button>
<button class="button">2</button>
<button class="button">3</button>

$('.button').on('click', function(){
	$('.button').removeClass('active');
	$(this).addClass('active');
});

@media screen and (min-device-width: 481px) {
   background-image: url(design/background.jpg);
}