document.addEventListener("DOMContentLoaded", () => {
  document.querySelectorAll(".js-back").forEach(el => {
    el.addEventListener("click", e => {
      e.preventDefault();
      if (document.referrer && history.length > 1) {
        history.back();
      } else {
        window.location.href = "index.html";
      }
    });
  });
});