pixel_perfect.js

var lastScrollTop = 0;
// Detect the scroll.
window.addEventListener(
  "scroll",
  function () {
    let st = window.pageYOffset || document.documentElement.scrollTop;

    if (st > lastScrollTop) {
      // Downscroll code
      // console.log("\n\ngoing down V\n\n");

      document.getElementById("box-shadow").classList.add("great");
    } else {
      // Upscroll code
      // console.log("\n\ngoing up ^\n\n");
      document.getElementById("box-shadow").classList.remove("great");
    }
    lastScrollTop = st <= 0 ? 0 : st; // For Mobile or negative scrolling
  },
  false
);

let n = 0;
document.querySelector("#menu-btn").addEventListener("click", () => {
  if ("click") {
    n++;
    console.log(n);
    if (n % 2 != 0) {
      document.querySelector("nav").classList.remove("responsive");
    } else {
      document.querySelector("nav").classList.add("responsive");
    }
  }
});