JavaScript, window.scrollTo, offset

scrollToOffset.js

function scrollToOffset(element, offset /* int */)
{
  //ref→https://newbedev.com/javascript-scrollintoview-smooth-scroll-and-offset
  const bodyRect = document.body.getBoundingClientRect().top;
  const elementRect = element.getBoundingClientRect().top;
  const elementPosition = elementRect - bodyRect;
  const offsetPosition = elementPosition - offset;
  window.scrollTo({
    top: offsetPosition,
    behavior: "smooth"
  });
}