export const getStreakColor = (days) => {
  if (days <= 3) return "bg-red-500";
  if (days <= 6) return "bg-yellow-400";
  if (days <= 9) return "bg-green-400";
  if (days <= 14) return "bg-green-500";
  if (days <= 21) return "bg-green-600";
  return "bg-emerald-700"; // elite tier
};