text: let btn = document.querySelector("#btn");
  let sidebar = document.querySelector(".sidebar");
  let searchBtn = document.querySelector(".bx-search");
  
  btn.onclick = function() {
      sidebar.classList.toggle("active");
  }
  
  searchBtn.onclick = function() {
      sidebar.classList.toggle("active");
  }
  
  function shearchTitle() {
      var input, filter, ul, li, a, i, txtValue;
      input = document.getElementById("search");
      filter = input.value.toUpperCase();
      ul = document.getElementById("nav_ul");
      li = ul.getElementsByTagName("li");
      for (i = 0; i < li.length; i++) {
          a = li[i].getElementsByTagName("a")[0];
          txtValue = a.textContent || a.innerText;
          if (txtValue.toUpperCase().indexOf(filter) > -1) {
              li[i].style.display = "";
          } else {
              li[i].style.display = "none";
          }
      }
  }