popov.link/_scss/components/_navigation.scss

.navigation-container {
  background: $color-bg;
  border-left: 1px solid $color-bg-alt;
  border-right: 1px solid $color-bg-alt;
  height: 100px;
  left: 0;
  margin: auto;
  max-width: 52em;
  padding: 0;
  position: fixed;
  right: 0;
  top: 0;
  width: 100%;
}

.toggle-button {
  display: none;

  &:checked ~ .navigation {
    transform: none;
    transition: all .1s;
  }

  &:checked ~ .toggle-label {
    span {
      opacity: 0;
      top: 50%;
    }

    span:first-child {
      opacity: 1;
      transform: rotate(405deg);
    }

    span:last-child {
      opacity: 1;
      transform: rotate(-405deg);
    }
  }
}

.toggle-label {
  float: right;
  height: 20px;
  position: relative;
  right: 40px;
  top: 40px;
  width: 15px;

  &:hover {
    cursor: pointer;
  }

  span {
    background: $color-text;
    height: 2px;
    position: absolute;
    top: 50%;
    width: 100%;

    &:first-child {
      top: 3px;
    }

    &:last-child {
      top: 16px;
    }
  }
}

.navigation {
  background: $color-bg;
  border-left: 1px solid $color-bg-alt;
  border-right: 1px solid $color-bg-alt;
  height: 100%;
  left: 0;
  margin: auto;
  max-width: 52em;
  padding: 0;
  position: fixed;
  right: 0;
  top: 100px;
  transform: scale(.1, 0);
  transform-origin: 100% 0%;
  transition: none;
  width: 100%;
}