ItemEvents.modification(event => {
  // Modify individual potion types
  event.modify('minecraft:potion', item => {
    item.maxStackSize = 16; // Adjust stack size
  });

  event.modify('minecraft:splash_potion', item => {
    item.maxStackSize = 16;
  });

  event.modify('minecraft:lingering_potion', item => {
    item.maxStackSize = 16;
  });
});
