ildi-wp/dev/scss/components/_header-menu.scss

.header-menu {
  display: flex;
  flex-direction: column;
  align-content: flex-start;
  align-items: flex-start;
  justify-content: flex-start;
  margin: 5px 0;
  padding: 0;
  width: 100%;
  list-style: none;
  line-height: 1;

  li {
    flex: 1 0 auto;
    margin: 0;
    padding: 0;
    width: 100%;
  }

  a {
    display: block;
    padding: $gutter 0;
    text-transform: uppercase;
    text-decoration: none;
    letter-spacing: 0.125ch;
    color: $di-purple;
    font-weight: 700;

    &:hover,
    &:active {
      background-color: $di-purple;
      color: $copy-light;
    }
  }
}

@media screen and (max-width: #{$screen-tablet - 1}) {
  .header-menu {
    margin-left: -$gutter;
    width: calc(100% + #{$gutter * 2});

    a {
      padding-right: $gutter;
      padding-left: $gutter;
    }
  }
}

@media screen and (min-width: $screen-tablet) {
  .header-menu {
    flex-direction: row;
    align-content: center;
    align-items: center;
    justify-content: space-around;

    li { width: auto; }

    li,
    a {
      text-align: center;
    }
  }
}