slider.addEventListener('mousedown', (e) => {
      isDown = true;
      startX = e.pageX - slider.offsetLeft;
      scrollLeft = slider.scrollLeft;
    });
    slider.addEventListener('mouseleave', () => {
      isDown = false;
    });
    slider.addEventListener('mouseup', () => {
      isDown = false;
    });
    slider.addEventListener('mousemove', (e) => {
      if(!isDown) return;
      e.preventDefault();
      const x = e.pageX - slider.offsetLeft;
      const walk = (x - startX) * 1;
      slider.scrollLeft = scrollLeft - walk;
    });