document.addEventListener("DOMContentLoaded", function() {
  var ageModal = document.getElementById("ageModal");
  var submitBtn = document.getElementById("submitBtn");
  var birthMonth = document.getElementById("birthMonth");
  var birthYear = document.getElementById("birthYear");
  var errorMsg = document.getElementById("errorMsg");

  if (ageModal && !localStorage.getItem("ageVerified")) {
    ageModal.classList.add("show");
    document.body.classList.add("modal-open");
  }

  if (submitBtn) {
    submitBtn.addEventListener("click", function() {
      var month = parseInt(birthMonth.value, 10);
      var year = parseInt(birthYear.value, 10);
      var today = new Date();

      if (!month || !year || month < 1 || month > 12 || year < 1900) {
        errorMsg.style.display = "block";
        return;
      }

      var age = today.getFullYear() - year;
      if ((today.getMonth() + 1) < month) age--;

      if (age < 18) {
        errorMsg.style.display = "block";
        return;
      }

      localStorage.setItem("ageVerified", "true");
      ageModal.classList.remove("show");
      document.body.classList.remove("modal-open");
    });
  }

  if (birthYear) {
    birthYear.addEventListener("keypress", function(e) {
      if (e.keyCode === 13 && submitBtn) submitBtn.click();
    });
  }

});