let dropdown = document.getElementsByClassName("dropdown__btn");

for (let i = 0; i < dropdown.length; i++) {
  dropdown[i].addEventListener("click", function() {
    this.classList.toggle("dropdown__btn--active");
    let dropdownContent = this.nextElementSibling;
    if (dropdownContent.style.display === "block") {
      dropdownContent.style.display = "none";
    } else {
      dropdownContent.style.display = "block";
    }
  });
}