Меню

<ul class="header-nav">
  <li class="dropdown-item">
    <a href="#">Товары</a>
        <ul class="sub-menu">
          <li>
            <a href="#">Товар 1</a>
          </li>
          <li>
            <a href="#">Товар 2</a>
          </li>
          <li>
            <a href="#">Товар 3</a>
          </li>                                               
        </ul>
  </li>
  <li class="dropdown-item">
    <a href="#">Услуги</a>
        <ul class="sub-menu">
          <li>
            <a href="#">Услуга 1</a>
          </li>
          <li>
            <a href="#">Услуга 2</a>
          </li>
          <li>
            <a href="#">Услуга 3</a>
          </li>                                               
        </ul>
  </li>
  <li>
    <a href="#">FAQ</a>
  </li>
  <li>
    <a href="#">Блог</a>
  </li>
  <li>
    <a href="#">Контакты</a>
  </li>
</ul>

.header-nav {
  display: flex;
  width: auto;
  align-items: center;
  flex-wrap: wrap;
  row-gap: 20px;
  column-gap: 32px;
  font-weight: 400;
  font-size: 18px;
  line-height: 133%;
  letter-spacing: -0.02em;
  list-style: none;
}

.header-nav .dropdown-item {
  position: relative;
}

.header-nav li > a {
  position: relative;
  color: #2e4a82;
}

.header-nav li > a::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: -3px;
  width: 0;
  height: 1px;
  background-color: #2e4a82;;
  transform: translateX(-50%);
  transition: width 0.3s ease;
}

.header-nav li > a:hover::after {
  width: 100%;
}

.header-nav .dropdown-item > a {
  padding-right: 24px;
}

.header-nav .dropdown-item > a::before {
  content: "";
  position: absolute;
  top: 9px;
  right: 0;
  display: inline-flex;
  width: 14px;
  aspect-ratio: 14/8;
  background: center / contain no-repeat url("data:image/svg+xml,%3Csvg width='14' height='8' viewBox='0 0 14 8' fill='none' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M12.4697 1.05812C12.7626 0.814042 13.2373 0.814042 13.5302 1.05812C13.8231 1.3022 13.8231 1.69783 13.5302 1.94191L7.53022 6.94191C7.23732 7.18599 6.76256 7.18599 6.46967 6.94191L0.46967 1.94191C0.176777 1.69783 0.176777 1.3022 0.46967 1.05812C0.762563 0.814042 1.23732 0.814042 1.53022 1.05812L6.99994 5.61622L12.4697 1.05812Z' fill='black'/%3E%3C/svg%3E");
  transition: transform 0.3s ease;
}

.sub-menu {
  position: absolute;
  top: 40px;
  left: 0;
  z-index: 10;
  width: max-content;
  padding: 15px 25px;
  background-color: #fff;
  border: 1px solid #000;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: opacity 0.2s ease, visibility 0.2s ease;
  list-style: none;
}

.sub-menu li {
  margin-bottom: 10px;
}

.sub-menu li a {
  font-size: 16px;
}

.sub-menu li:last-child {
  margin-bottom: 0;
}

.dropdown-item--opened > a::before {
  transform: rotate(180deg);
}

.dropdown-item--opened .sub-menu {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
}

.header-nav li.dropdown-item.dropdown-item--opened > a::after {
  width: 100%;
}

.header-nav .sub-menu li a::after {
    display: none;
}

@media (max-width: 500px) {
  
  .header-nav {
    flex-direction: column;
    align-items: flex-start;
    row-gap: 20px;
  }

  .sub-menu {
    position: static;
    opacity: 1;
    visibility: visible;
    pointer-events: initial;
    padding: 12px 0px 0px 6px;
    border: none;
    background-color: transparent;
  }

  .header-nav .dropdown-item > a::before {
    display: none;
  }

  .header-nav .dropdown-item > a {
    padding-right: 0;
  }

}

const dropdownItems = document.querySelectorAll('.dropdown-item');

if (dropdownItems.length) {
  dropdownItems.forEach(item => {
    const link = item.firstElementChild;
    if (link && link.tagName.toLowerCase() === 'a') {
      link.addEventListener('click', e => {
        e.preventDefault();
      });
    }

    item.addEventListener('click', e => {
      e.stopPropagation();

      dropdownItems.forEach(el => {
        if (el !== item) {
          el.classList.remove('dropdown-item--opened');
        }
      });

      item.classList.toggle('dropdown-item--opened');
    });
  });

  document.addEventListener('click', e => {
    if (!e.target.closest('.dropdown-item')) {
      dropdownItems.forEach(el => el.classList.remove('dropdown-item--opened'));
    }
  });
}