var lastScrollTop = 0;
// element should be replaced with the actual target element on which you have applied scroll, use window in case of no target element.
element.addEventListener("scroll", function(){ // or window.addEventListener("scroll"....
   var st = window.pageYOffset || document.documentElement.scrollTop; 
   if (st > lastScrollTop){
      // downscroll code
   } else {
      // upscroll code
   }
   lastScrollTop = st <= 0 ? 0 : st; // For Mobile or negative scrolling
}, false);
.works__content - text-align: right;
.slider вместо маржина display: inline-block;