app/common/styles/layout/navigation.scss

$nav__toplvlWidth: 120px;
$nav__seclvlWidth: 240px;

// Top level navigation
#nav__top-level {
  background: $nav__top-level-color;
  height: 100%;
  position: fixed;
  left: 0;
  top: 0;
  bottom: 0;
  z-index: 99;
  list-style-type: none;
  margin: 0;
  padding: 0;
  width: $nav__toplvlWidth;
  display: block;
  li {
    margin: 0;
  }
  .button, button, a {
    background: transparent;
    height: auto;
    border: 0;
    color: $white;
    fill: $white;
    width: 100%;
    padding: 1em;
    display: block;
    text-align: center;
    margin-bottom: 0;
    white-space: normal;
    border-radius: 0;
    text-decoration: none;
    .nav__icon {
      color: $white;
      max-height: 40px;
      stroke-width: .5;
      margin-bottom: -.5em;
    }
    a {
      margin-bottom: 5px;
    }
    span {
      margin: 1em 0 0 0;
      display: block;
      font-size: .9em;
      font-weight: normal;
      line-height: 1rem;
    }

    .nav__icon-help__outer {
      fill: transparent;
      stroke: $white;
      stroke-miterlimit: 10;
      stroke-width: 1px;
    }
    .nav__icon-help__Inner {
      fill: $white;
    }
    &:hover {
      background: $nav__second-level-color;
      fill: $black;
      color: $black;
      padding: 1em;
      border-radius: 0;
      .nav__icon-help__outer {
        stroke: $black;
      }
      .nav__icon-help__inner {
        fill: $lightbg__primary;
      }
    }
  }
  .opened {
    background: $nav__second-level-color;
    fill: $black;
    color: $black;
    .nav__icon-help__outer {
      stroke: $lightbg__primary;
    }
  }
}

// Second Level Navigation
.nav__second-level {
  position: fixed;
  background: $nav__second-level-color;
  top: 0;
  bottom: 0;
  left: 0;
  width: $nav__seclvlWidth;
  z-index: 0;
  padding: 0;
  margin: 0;
  display: none;
  list-style-type: none;
  @include fastTransition-all;
  @include mediaQuery(medium) {
    left: 0;
    &.btn-overview {
      display: none;
    }
  }
  &.opened {
    left: $nav__toplvlWidth;
    z-index: 100;
    display: block;
    @include fastTransition-all;
  }

  a {
    padding: 1.2em 1em 1.2em 1em;
    display: block;
    color: $black;
    text-decoration: none;
    position: relative;
    font-weight: 400;
  }
  li {
    a:after{
      content: '\203A';
      position: absolute;
      font-size: 2em;
      font-weight: 700;
      top: 50%;
      right: .6em;
      transform: translateY(-59%);
      color: #4b5d78;
      opacity: 0;
    }
    &.active {background: $white;}
    &.active,
    &:focus,
    &:hover {
      a {color: #4b5d78;}
      a:after {
        opacity: 1;
        right: .3em;
        @include fastTransition-all;
      }
    }
  }
}