text: document.addEventListener("DOMContentLoaded", () => {
    document.getElementById("toggle_btn").addEventListener("click", () => {
      if (document.getElementById("header").classList.contains("open")) {
        document.getElementById("header").classList.remove("open");
      } else {
        document.getElementById("header").classList.add("open");
      }
    });
  
    document.getElementById("mask").addEventListener("click", () => {
      document.getElementById("header").classList.remove("open");
    });
  });
  