<nav class="menu">
  <ol>
    <li class="menu-item active"><a href="#0">Home</a></li>
    <li class="menu-item"><a href="#0">About</a></li>
    <li class="menu-item">
      <a href="#0">Widgets</a>
      <ol class="sub-menu">
        <li class="menu-item"><a href="#0">Big Widgets</a></li>
        <li class="menu-item"><a href="#0">Bigger Widgets</a></li>
        <li class="menu-item"><a href="#0">Huge Widgets</a></li>
      </ol>
    </li>
    <li class="menu-item">
      <a href="#0">Kabobs</a>
      <ol class="sub-menu">
        <li class="menu-item"><a href="#0">Shishkabobs</a></li>
        <li class="menu-item"><a href="#0">BBQ kabobs</a></li>
        <li class="menu-item"><a href="#0">Summer kabobs</a></li>
      </ol>
    </li>
    <li class="menu-item"><a href="#0">Contact</a></li>
  </ol>
</nav>

$yellow: #f4d03f;
$blue: #16a085;
$gradient-bg: linear-gradient(90deg, $blue, $yellow);
$transparent-gray: rgba(0, 0, 0, 0.3);
$transparent-white: rgba(255, 255, 255, 0.15);

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

body {
  background: $gradient-bg;
  font-family: "Montserrat", sans-serif;
  color: #fff;

  // For codepen only
  height: 100vh;
}

.menu {
  ol {
    list-style: none;
    padding: 0;
    margin: 0;

    &:first-child {
      width: 100%;
      max-width: 960px;
      margin: 1rem auto 0 auto;
      display: grid;
      grid-template-columns: repeat(5, 1fr);
      align-items: center;
      box-shadow: 0px 3px 8px $transparent-gray;
    }
  }

  &-item {
    display: flex;
    align-items: center;
    justify-content: center;
    border-top: 2px solid $blue;
    position: relative;
    transition: background 0.3s ease-in-out;

    &:nth-child(1) > a::before {
      content: "\f015";
    }

    &:nth-child(2) > a::before {
      content: "\f05a";
    }

    &:nth-child(3) > a::before {
      content: "\f0ad";
    }

    &:nth-child(4) > a::before {
      content: "\f2e7";
    }

    &:nth-child(5) > a::before {
      content: "\f007";
    }

    @for $i from 1 through 5 {
      &:nth-child(#{$i}) > a::before {
        font-family: "Font Awesome 5 Free";
        font-size: 1.2rem;
        display: block;
        margin-bottom: 1rem;
        font-weight: 900;
        -moz-osx-font-smoothing: grayscale;
        -webkit-font-smoothing: antialiased;
        display: inline-block;
        font-style: normal;
        font-variant: normal;
        text-rendering: auto;
        line-height: 1;
        color: $blue;

        @media (min-width: 768px) {
          font-size: 1.5rem;
        }
      }
    }

    .sub-menu > a {
      color: red;
    }

    &:not(:last-child) {
      border-right: 1px solid $transparent-white;
    }

    .sub-menu {
      position: absolute;
      top: 100%;
      width: 100%;
      transform-origin: top;
      transform: rotateX(-90deg);
      transition: transform 0.3s linear;
      background-color: $yellow;

      .menu-item {
        border-color: $transparent-white;

        a::before {
          content: "";
        }

        &:first-child {
          border: 0;
        }
      }
    }

    &:hover,
    &.active {
      border-top: 2px solid $yellow;
      background-color: $transparent-white;

      a::before {
        color: white;
      }
    }

    &:hover .sub-menu {
      transform: rotateX(0deg);
    }

    a {
      font-size: 0.8rem;
      display: flex;
      flex-direction: column;
      align-items: center;
      color: #fff;
      text-decoration: none;
      text-transform: uppercase;
      height: 100%;
      width: 100%;
      padding: 1.5em 1em;

      @media (min-width: 768px) {
        font-size: 1rem;
      }
    }
  }
}

// Inspired by https://dribbble.com/shots/1075480-Ui-Kit-Hotel