<header class="page-header">
  <nav>
    <div class="trigger-menu-wrapper">
      <button class="trigger-menu">
        <svg width="12" height="12" viewBox="0 0 24 24">
          <path d="M24 10h-10v-10h-4v10h-10v4h10v10h4v-10h10z" />
        </svg>
        <span>MENU</span>
      </button>
    </div>
    <ul class="menu">
      <li>
        <a href="">About</a>
        <ul class="sub-menu">
          <li>
            <a href="">History</a>
          </li>
          <li>
            <a href="">President</a>
          </li>
          <li>
            <a href="">Team</a>
          </li>
          <li>
            <a href="">Process</a>
          </li>
          <li>
            <a href="">Clients</a>
          </li>
        </ul>
      </li>
      <li>
        <a href="">Services</a>
      </li>
      <li>
        <a href="">Portfolio</a>
        <ul class="sub-menu">
          <li>
            <a href="">Case Studies</a>
          </li>
          <li>
            <a href="">Awards</a>
          </li>
        </ul>
      </li>
      <li>
        <a href="">Blog</a>
      </li>
      <li>
        <a href="">Contact</a>
      </li>
    </ul>
  </nav>
</header>

<a href="" role="button" aria-label="Toggle menu" class="lottie-wrapper">
  <lottie-player src="https://assets10.lottiefiles.com/datafiles/9gIwZ2uiiKglyb0/data.json" style="width: 60px; height: 60px;"></lottie-player>
</a>

<main class="page-main">
  <section style="background-image:url(https://s3-us-west-2.amazonaws.com/s.cdpn.io/162656/freedom.jpg);"></section>
  <section style="background-image:url(https://s3-us-west-2.amazonaws.com/s.cdpn.io/162656/travel.jpg);"></section>
  <section style="background-image:url(https://s3-us-west-2.amazonaws.com/s.cdpn.io/162656/holidays.jpg);"></section>
</main>

<footer class="page-footer">
  <span>made by </span>
  <a href="https://georgemartsoukos.com/" target="_blank">
    <img width="24" height="24" src="https://assets.codepen.io/162656/george-martsoukos-small-logo.svg" alt="George Martsoukos logo">
  </a>
</footer>

/* RESET RULES
–––––––––––––––––––––––––––––––––––––––––––––––––– */
:root {
  --white: #fff;
  --black: #221f1f;
  --lightpurple: #9e91f2;
  --darkgray: #1e1f26;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

button {
  background: transparent;
  border: none;
  cursor: pointer;
  outline: none;
}

ul {
  list-style: none;
}

a {
  text-decoration: none;
  color: inherit;
}

body {
  position: relative;
  font: 16px/1.5 sans-serif;
  color: var(--white);
}


/* MAIN RULES
–––––––––––––––––––––––––––––––––––––––––––––––––– */
.trigger-menu-wrapper {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  display: flex;
  justify-content: center;
  padding: 20px;
  z-index: 2;
  background: var(--lightpurple);
  transition: transform 0.4s;
}

.page-header .trigger-menu {
  display: flex;
  align-items: center;
  font-size: 1.3rem;
  color: var(--white);
  letter-spacing: 0.2em;
}

.page-header .trigger-menu svg {
  fill: var(--white);
  margin-right: 8px;
  transition: transform 0.3s;
}

.page-header .menu {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  display: none;
  text-align: center;
  padding: 15vh 0 5vh;
  overflow: auto;
  z-index: 1;
  background: var(--lightpurple);
}

.page-header .menu a {
  font-size: 3rem;
}

.page-header .sub-menu a {
  font-size: 1.5rem;
}

.lottie-wrapper {
  position: fixed;
  bottom: 50px;
  right: 25px;
  z-index: 1;
  padding: 5px;
  border-radius: 5px;
}

.page-main section {
  position: relative;
  background-repeat: no-repeat;
  background-position: center;
  background-size: cover;
  height: 100vh;
}

.page-main section::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.25);
}


/* BODY CLASSES
–––––––––––––––––––––––––––––––––––––––––––––––––– */
.menu-open {
  overflow: hidden;
}

.menu-open .trigger-menu-wrapper {
  background: transparent;
}

.menu-open .page-header .menu {
  display: block;
}

.menu-open .page-header svg {
  transform: rotate(45deg);
}

.menu-open-with-lottie .page-header .menu {
  padding: 5vh 0;
}

.scroll-down .trigger-menu-wrapper {
  transform: translate3d(0, -100%, 0);
}

.scroll-down .lottie-wrapper {
  background: var(--darkgray);
}

.scroll-up .trigger-menu-wrapper {
  transform: none;
}

.scroll-up:not(.menu-open) .trigger-menu-wrapper {
  background: var(--lightpurple);
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.35);
}


/* FOOTER
–––––––––––––––––––––––––––––––––––––––––––––––––– */
.page-footer {
  position: fixed;
  right: 25px;
  bottom: 10px;
  display: flex;
  align-items: center;
  font-size: 1rem;
  padding: 5px;
  border-radius: 5px;
  background: var(--darkgray);
}

.page-footer a {
  display: flex;
  margin-left: 4px;
}

const body = document.body;
const triggerMenu = document.querySelector(".page-header .trigger-menu");
const nav = document.querySelector(".page-header nav");
const menu = document.querySelector(".page-header .menu");
const lottieWrapper = document.querySelector(".lottie-wrapper");
const lottiePlayer = document.querySelector("lottie-player");
const scrollUp = "scroll-up";
const scrollDown = "scroll-down";
let lastScroll = 0;

triggerMenu.addEventListener("click", () => {
  body.classList.toggle("menu-open");
});

lottieWrapper.addEventListener("click", (e) => {
  e.preventDefault();
  triggerMenu.click();
  body.classList.toggle("menu-open-with-lottie");
});

window.addEventListener("scroll", () => {
  const currentScroll = window.pageYOffset;
  if (currentScroll <= 0) {
    body.classList.remove(scrollUp);
    return;
  }

  if (currentScroll > lastScroll && !body.classList.contains(scrollDown)) {
    // down
    body.classList.remove(scrollUp);
    body.classList.add(scrollDown);
    lottiePlayer.play();
  } else if (
    currentScroll < lastScroll &&
    body.classList.contains(scrollDown)
  ) {
    // up
    body.classList.remove(scrollDown);
    body.classList.add(scrollUp);
    lottiePlayer.stop();
  }
  lastScroll = currentScroll;
});