// light follows the cursor across a card's glass
document.querySelectorAll('.shard').forEach(el=>{
  el.addEventListener('pointermove',e=>{
    const r=el.getBoundingClientRect();
    el.style.setProperty('--mx',(e.clientX-r.left)+'px');
    el.style.setProperty('--my',(e.clientY-r.top)+'px');
  });
  el.addEventListener('pointerleave',()=>{el.style.removeProperty('--mx');el.style.removeProperty('--my')});
});