$(window).resize(function(){ 
if (window.innerWidth > 768) { // 다바이스 크기가 480이상일때

 $('.slider-nav').slick({
   slidesToShow: 3,
   slidesToScroll: 1,
   dots: true,
   focusOnSelect: true,
   autoplay:true,
   autoplaySpeed:3000,
 });
      

} else {

 $('.slider-nav').slick({
   slidesToShow: 1,
   slidesToScroll: 1,
   dots: true,
   focusOnSelect: true,
   autoplay:true,
   autoplaySpeed:3000,
 });
       
} 
}).resize();