.header {
  position: relative;
  z-index: 99;
}

.header-nav__trigger {
  width: 3rem;
  height: 3rem;
  display: flex;
  cursor: pointer;
  position: relative;
  background-color: var(--cobalt);
  border-radius: 0.5rem;

  & .header-nav__trigger-toggle {
    top: 50%;
    left: 50%;
    transform-origin: center;
    transform: translate(-50%, -50%);
    border-radius: 1px;
    height: 2px;
    width: 1.25rem;
    display: block;
    background-color: var(--white);
    position: absolute;
    transition: all 150ms ease;

    &::before,
    &::after {
      content: "";
      top: 0;
      left: 0;
      border-radius: 1px;
      height: 2px;
      width: 1.25rem;
      display: block;
      background-color: var(--white);
      position: absolute;
      transition: all 150ms ease;
    }

    &::before {
      animation: toggler-top 800ms ease forwards;
    }

    &::after {
      animation: toggler-bottom 800ms ease forwards;
    }
  }

  &.active .header-nav__trigger-toggle {
    transition-delay: 200ms;
    transform: translate(-50%, -50%) rotate(135deg);

    &::before {
      animation: toggler-top-open 800ms ease forwards;
    }

    &::after {
      animation: toggler-bottom-open 800ms ease forwards;
    }
  }
}

.header-nav__content {
  position: fixed;
  top: 0;
  left: 0;
  padding-top: 6rem;
  height: 100%;
  width: 100%;
  background-color: var(--white);
  transition: all 400ms ease;
  overflow-y: auto;
  overflow-x: hidden;
  -webkit-overflow-scrolling: touch;
  z-index: -1;
  color: var(--ink);
}

@media screen and (min-width: 1200px) {
  .header-nav__content,
  .header-nav__trigger {
    display: none;
  }
}

.side-nav {
  position: fixed;
  top: 17.5rem;
  right: 0;
  display: none;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1rem;
  border-top-left-radius: 0.5rem;
  border-bottom-left-radius: 0.5rem;
  writing-mode: vertical-rl;
  background-color: var(--cobalt);
  z-index: 5;
  line-height: 1;
  font-weight: 700;
  transition: opacity ease 200ms;
  & > p {
    background-color: var(--snow);
    padding: 0.375rem 0.375rem 0.25rem 0.25rem;
    border-radius: 9999px;
    color: var(--cobalt);
    letter-spacing: 0.2em;
    font-size: 0.75rem;
  }
  & > div {
    display: flex;
    align-items: center;
    color: var(--snow);
    letter-spacing: 0.15em;
    & p:last-child {
      transform: rotate(-90deg) translateY(0.125rem);
    }
  }
  &:hover {
    opacity: 90%;
    text-decoration: none;
  }
  @media screen and (min-width: 1200px) {
    display: flex;
  }
}

/** Keyframes **/
@keyframes toggler-top-open {
  0% {
    transform: translateY(6px);
  }

  30% {
    transform: translateY(0);
  }

  to {
    transform: translateY(0);
  }
}

@keyframes toggler-bottom-open {
  0% {
    transform: translateY(-6px);
  }

  30% {
    transform: translateY(0);
  }

  to {
    transform: translateY(0) rotate(90deg);
  }
}

@keyframes toggler-bottom {
  0% {
    transform: translateY(0);
  }

  30% {
    transform: translateY(0);
  }

  to {
    transform: translateY(6px);
  }
}

@keyframes toggler-top {
  0% {
    transform: translateY(0) rotate(90deg);
  }

  30% {
    transform: translateY(0);
  }

  to {
    transform: translateY(-6px);
  }
}

/**
 * 開発時にLoading Spinnerで隠れないようにするためのスタイル
 */
.loading-spinner {
  display: none;
}