.page-lower {
  background:
    radial-gradient(circle at 8% 8%, rgba(210, 247, 255, .8), transparent 22rem),
    radial-gradient(circle at 92% 18%, rgba(226, 250, 255, .78), transparent 20rem),
    #fff;
}

.page-lower .lower-main {
  overflow-x: clip;
  background:
    radial-gradient(circle at 12% 28rem, rgba(148, 231, 248, .18), transparent 13rem),
    radial-gradient(circle at 90% 45rem, rgba(157, 233, 246, .18), transparent 14rem),
    #fff;
}

.lower-header .site-header__brand {
  width: clamp(156px, 15vw, 224px);
}

.lower-breadcrumb,
.lower-hero__inner,
.lower-nav,
.lower-page-nav,
.lower-content,
.lower-related,
.lower-pager,
.lower-back {
  width: min(100% - 48px, 1160px);
  margin-right: auto;
  margin-left: auto;
}

.lower-breadcrumb {
  padding: clamp(1rem, 2vw, 1.6rem) 0 0;
  color: #38698e;
  font-size: clamp(.78rem, .85vw, .92rem);
}

.lower-breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: .35rem .55rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.lower-breadcrumb li {
  display: inline-flex;
  align-items: center;
  gap: .55rem;
}

.lower-breadcrumb li + li::before {
  width: .42em;
  height: .42em;
  content: "";
  border-top: 1.5px solid currentColor;
  border-right: 1.5px solid currentColor;
  opacity: .62;
  transform: rotate(45deg);
}

.lower-breadcrumb a {
  text-decoration: underline;
  text-decoration-color: rgba(42, 148, 214, .38);
  text-underline-offset: .22em;
}

.lower-hero {
  position: relative;
  isolation: isolate;
  padding: clamp(1.4rem, 3vw, 2.8rem) 0 clamp(2.5rem, 5vw, 4.8rem);
}

.lower-hero::before,
.lower-hero::after {
  position: absolute;
  z-index: -1;
  content: "";
  pointer-events: none;
}

.lower-hero::before {
  top: 16%;
  left: 4%;
  width: clamp(78px, 9vw, 150px);
  aspect-ratio: 1;
  background: url("../images/common/bubble03.png") center / contain no-repeat;
  opacity: .48;
}

.lower-hero::after {
  right: 5%;
  bottom: 7%;
  width: clamp(70px, 8vw, 130px);
  aspect-ratio: 1;
  background: url("../images/common/kai01.png") center / contain no-repeat;
  opacity: .5;
  transform: rotate(18deg);
}

.lower-hero__inner {
  display: grid;
  grid-template-columns: minmax(0, .95fr) minmax(320px, .78fr);
  align-items: center;
  gap: clamp(1.6rem, 4vw, 4.2rem);
  padding: clamp(1.2rem, 2.6vw, 2.3rem);
  background:
    radial-gradient(circle at 8% 14%, rgba(255, 255, 255, .98), transparent 10rem),
    linear-gradient(135deg, #fff 0%, #f1fbff 52%, #dff7fb 100%);
  border: 1px solid rgba(42, 148, 214, .2);
  border-radius: 8px;
  box-shadow: 0 18px 45px rgba(12, 111, 172, .12);
}

.lower-hero__content {
  min-width: 0;
}

.lower-hero__label,
.lower-section__eyebrow,
.lower-nav__heading {
  margin: 0 0 .7rem;
  color: #1f7ed1;
  font-size: clamp(.76rem, .84vw, .9rem);
  font-weight: 700;
  line-height: 1.3;
  letter-spacing: .12em;
}

.lower-hero__label {
  display: inline-flex;
  align-items: center;
  gap: .45rem;
  min-height: 34px;
  padding: .32rem .95rem;
  color: #075eae;
  background: rgba(255, 255, 255, .86);
  border: 1px solid rgba(42, 148, 214, .28);
  border-radius: 999px;
}

.lower-hero__label::before {
  width: .58rem;
  aspect-ratio: 1;
  content: "";
  background: #9fe9f6;
  border-radius: 50%;
  box-shadow: .62rem .15rem 0 rgba(159, 233, 246, .55);
}

.lower-hero__title {
  margin: 0;
  color: #00488f;
  font-size: clamp(2rem, 5vw, 4.2rem);
  font-weight: 700;
  line-height: 1.22;
  letter-spacing: 0;
}

.lower-hero__title::after {
  display: block;
  width: min(320px, 68vw);
  height: 16px;
  margin-top: .62rem;
  content: "";
  background: url("data:image/svg+xml,%3Csvg width='420' height='18' viewBox='0 0 420 18' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M6 10c31-17 54 12 88-1 34-13 62-13 96 0s63 13 98 0 62-14 126 0' fill='none' stroke='%238bd0f2' stroke-width='3' stroke-linecap='round' opacity='.8'/%3E%3C/svg%3E") center / contain no-repeat;
}

.lower-hero__lead {
  max-width: 43rem;
  margin: clamp(1rem, 2vw, 1.5rem) 0 0;
  color: #17365d;
  font-size: clamp(1rem, 1.35vw, 1.18rem);
  line-height: 2;
}

.lower-hero__visual {
  position: relative;
  overflow: hidden;
  container-type: inline-size;
  margin: 0;
  aspect-ratio: 4 / 3;
  background:
    radial-gradient(circle at 28% 24%, rgba(255, 255, 255, .8), transparent 28%),
    linear-gradient(180deg, #effbff 0%, #cfedf7 100%);
  border: 1px solid rgba(42, 148, 214, .2);
  border-radius: 8px;
  box-shadow: inset 0 0 0 6px rgba(255, 255, 255, .62);
}

.lower-hero__visual::after {
  position: absolute;
  right: -12%;
  bottom: -22%;
  left: -12%;
  height: 44%;
  content: "";
  background: rgba(159, 233, 246, .42);
  border-radius: 50% 50% 0 0;
  transform: rotate(-2deg);
}

.lower-hero__visual::before {
  position: absolute;
  right: clamp(.55rem, 2.4cqw, 1rem);
  bottom: clamp(.55rem, 2.4cqw, 1rem);
  z-index: 4;
  color: #fff;
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(8px, 2.6cqw, 15px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: .03em;
  white-space: nowrap;
  content: "(C)TOBA AQUARIUM";
  text-shadow: 0 1px 3px rgba(0, 31, 56, .72);
  pointer-events: none;
}

.lower-hero__visual img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
}

.lower-nav {
  margin-top: clamp(.3rem, 1vw, .8rem);
  padding: clamp(1rem, 2vw, 1.5rem);
  background: rgba(255, 255, 255, .92);
  border: 1px solid rgba(42, 148, 214, .22);
  border-radius: 8px;
  box-shadow: 0 14px 34px rgba(12, 111, 172, .1);
}

.lower-nav__heading {
  color: #00488f;
  text-align: center;
}

.lower-nav__list {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: .7rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.lower-nav__item {
  display: flex;
  align-items: center;
  gap: .45rem;
  min-height: 54px;
  padding: .72rem .8rem;
  color: #17365d;
  font-size: clamp(.78rem, .85vw, .92rem);
  font-weight: 700;
  line-height: 1.45;
  background: #f7fdff;
  border: 1px solid rgba(42, 148, 214, .18);
  border-radius: 8px;
  transition: transform .2s ease, border-color .2s ease, background-color .2s ease, box-shadow .2s ease;
}

.lower-nav__item span {
  display: grid;
  flex: 0 0 auto;
  place-items: center;
  width: 1.85rem;
  aspect-ratio: 1;
  color: #fff;
  font-size: .82rem;
  line-height: 1;
  background: #2a94d6;
  border-radius: 50%;
}

.lower-nav__item:hover,
.lower-nav__item:focus-visible,
.lower-nav__item--active {
  color: #00488f;
  background: #fff;
  border-color: rgba(31, 126, 209, .48);
  box-shadow: 0 10px 20px rgba(12, 111, 172, .12);
  transform: translateY(-2px);
}

.lower-nav__item--active span {
  background: #00488f;
}

.lower-page-nav {
  position: sticky;
  top: 78px;
  z-index: 10;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: .55rem;
  margin-top: clamp(1.4rem, 3vw, 2.6rem);
  padding: .72rem;
  background: rgba(255, 255, 255, .9);
  border: 1px solid rgba(42, 148, 214, .18);
  border-radius: 999px;
  backdrop-filter: blur(10px);
}

.lower-page-nav a {
  display: inline-flex;
  align-items: center;
  min-height: 38px;
  padding: .45rem .95rem;
  color: #075eae;
  font-size: .9rem;
  font-weight: 700;
  line-height: 1.35;
  background: #f5fcff;
  border-radius: 999px;
}

.lower-content {
  display: grid;
  gap: clamp(1.6rem, 3vw, 2.6rem);
  margin-top: clamp(1.8rem, 4vw, 3.8rem);
}

.lower-section,
.lower-note {
  position: relative;
  padding: clamp(1.4rem, 3vw, 2.8rem);
  background: rgba(255, 255, 255, .94);
  border: 1px solid rgba(42, 148, 214, .18);
  border-radius: 8px;
  box-shadow: 0 16px 34px rgba(12, 111, 172, .08);
}

.lower-section h2,
.lower-note h2,
.lower-related h2 {
  margin: 0 0 clamp(.8rem, 1.5vw, 1.15rem);
  color: #00488f;
  font-size: clamp(1.45rem, 2.6vw, 2.25rem);
  line-height: 1.38;
  letter-spacing: 0;
}

.lower-section h3,
.lower-card h3 {
  margin: 0 0 .55rem;
  color: #075eae;
  font-size: clamp(1.08rem, 1.6vw, 1.28rem);
  line-height: 1.45;
}

.lower-section p,
.lower-note p,
.lower-card p {
  margin: 0;
  color: #17365d;
  font-size: clamp(.98rem, 1.08vw, 1.08rem);
  line-height: 2;
}

.lower-section p + p {
  margin-top: 1em;
}

.lower-media {
  display: grid;
  grid-template-columns: minmax(280px, .86fr) minmax(0, 1fr);
  align-items: center;
  gap: clamp(1.2rem, 3vw, 2.6rem);
}

.lower-media__image {
  position: relative;
  overflow: hidden;
  container-type: inline-size;
  aspect-ratio: 4 / 3;
  background: #effbff;
  border-radius: 8px;
}

.lower-media__image::after {
  position: absolute;
  right: clamp(.55rem, 2.4cqw, 1rem);
  bottom: clamp(.55rem, 2.4cqw, 1rem);
  z-index: 4;
  color: #fff;
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(8px, 2.6cqw, 15px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: .03em;
  white-space: nowrap;
  content: "(C)TOBA AQUARIUM";
  text-shadow: 0 1px 3px rgba(0, 31, 56, .72);
  pointer-events: none;
}

.lower-media__image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
}

.lower-link,
.lower-back__button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: .4rem;
  min-height: 44px;
  margin-top: 1.2rem;
  padding: .55rem 1.25rem;
  color: #fff;
  font-weight: 700;
  line-height: 1.3;
  background: linear-gradient(180deg, #4ca5e5 0%, #1f7ed1 100%);
  border-radius: 999px;
  box-shadow: 0 10px 20px rgba(23, 111, 197, .18);
}

.lower-link::after,
.lower-back__button::after {
  width: .46em;
  aspect-ratio: 1;
  content: "";
  border-top: 2px solid currentColor;
  border-right: 2px solid currentColor;
  transform: rotate(45deg);
}

.lower-column {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(1rem, 2vw, 1.4rem);
}

.lower-card {
  min-height: 100%;
  padding: clamp(1rem, 2vw, 1.4rem);
  background:
    radial-gradient(circle at 95% 8%, rgba(159, 233, 246, .32), transparent 5rem),
    #f8fdff;
  border: 1px solid rgba(42, 148, 214, .18);
  border-radius: 8px;
}

.lower-note {
  background:
    linear-gradient(90deg, rgba(255, 255, 255, .94), rgba(245, 253, 255, .94)),
    #fff;
  border-left: 6px solid #9fe9f6;
}

.lower-section--notice {
  background: #fffdf7;
  border-color: rgba(214, 170, 74, .24);
}

.lower-section--notice h2 {
  color: #7b5b16;
}

.lower-faq {
  display: grid;
  gap: .85rem;
}

.lower-faq details {
  padding: 0;
  background: #f7fdff;
  border: 1px solid rgba(42, 148, 214, .2);
  border-radius: 8px;
}

.lower-faq summary {
  min-height: 52px;
  padding: .9rem 1.1rem;
  color: #00488f;
  font-weight: 700;
  cursor: pointer;
}

.lower-faq details p {
  padding: 0 1.1rem 1rem;
}

.page-lower--3d-skeleton .lower-hero__visual {
  display: grid;
  place-items: center;
  background: #000;
  box-shadow:
    inset 0 0 0 1px rgba(255, 255, 255, .08),
    0 18px 45px rgba(12, 111, 172, .12);
}

.page-lower--3d-skeleton .lower-hero__visual img {
  width: 100%;
  height: auto;
  object-fit: contain;
}

.otter-3d-section {
  position: relative;
}

.otter-3d-viewer-wrap {
  max-width: 1000px;
  margin: 40px auto 0;
  padding: 16px;
  background: #000;
  border-radius: 24px;
  box-shadow: 0 24px 60px rgba(0, 48, 96, .22);
}

.otter-3d-viewer {
  display: block;
  width: 100%;
  height: min(68vh, 680px);
  min-height: 560px;
  background: #000;
  border-radius: 16px;
  overflow: hidden;
  --poster-color: #000;
  --progress-bar-color: #9fe9f6;
  --progress-bar-height: 4px;
}

.otter-3d-loading {
  display: grid;
  place-items: center;
  width: 100%;
  height: 100%;
  min-height: 360px;
  color: #fff;
  background: #000;
  font-size: .95rem;
  line-height: 1.6;
  letter-spacing: .04em;
  text-align: center;
}

.otter-3d-caption {
  max-width: 1000px;
  margin: 16px auto 0;
  color: #17365d;
  font-size: .95rem;
  line-height: 1.8;
}

.lower-related {
  margin-top: clamp(2.2rem, 5vw, 4.4rem);
}

.lower-related__heading {
  text-align: center;
}

.lower-related__grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(1rem, 2vw, 1.4rem);
}

.lower-related__card {
  display: grid;
  gap: .42rem;
  min-height: 150px;
  padding: clamp(1rem, 2vw, 1.4rem);
  background:
    radial-gradient(circle at 90% 18%, rgba(159, 233, 246, .36), transparent 5.8rem),
    #fff;
  border: 1px solid rgba(42, 148, 214, .2);
  border-radius: 8px;
  box-shadow: 0 14px 30px rgba(12, 111, 172, .08);
  transition: transform .2s ease, box-shadow .2s ease;
}

.lower-related__card span {
  display: grid;
  place-items: center;
  width: 2rem;
  aspect-ratio: 1;
  color: #fff;
  font-weight: 700;
  background: #2a94d6;
  border-radius: 50%;
}

.lower-related__card strong {
  color: #00488f;
  font-size: clamp(1rem, 1.35vw, 1.15rem);
  line-height: 1.45;
}

.lower-related__card em {
  color: #38698e;
  font-size: .92rem;
  font-style: normal;
  line-height: 1.5;
}

.lower-pager {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  margin-top: clamp(1.6rem, 4vw, 3rem);
}

.lower-pager__item {
  display: grid;
  gap: .2rem;
  min-height: 92px;
  padding: 1rem 1.2rem;
  background: #f7fdff;
  border: 1px solid rgba(42, 148, 214, .2);
  border-radius: 8px;
}

.lower-pager__item span {
  color: #38698e;
  font-size: .82rem;
  line-height: 1.35;
}

.lower-pager__item strong {
  color: #00488f;
  line-height: 1.45;
}

.lower-pager__item--prev {
  text-align: left;
}

.lower-pager__item--next {
  text-align: right;
}

.lower-back {
  display: flex;
  justify-content: center;
  padding: clamp(2rem, 5vw, 4.5rem) 0 clamp(1rem, 2vw, 2rem);
}

.lower-back__button {
  margin-top: 0;
}

.lower-nav__item:focus-visible,
.lower-page-nav a:focus-visible,
.lower-link:focus-visible,
.lower-related__card:focus-visible,
.lower-pager__item:focus-visible,
.lower-back__button:focus-visible,
.lower-breadcrumb a:focus-visible,
.lower-faq summary:focus-visible {
  outline: 3px solid rgba(42, 148, 214, .42);
  outline-offset: 3px;
}

.lower-related__card:hover,
.lower-related__card:focus-visible,
.lower-pager__item:hover,
.lower-pager__item:focus-visible,
.lower-page-nav a:hover,
.lower-link:hover,
.lower-back__button:hover {
  transform: translateY(-2px);
}

@media (max-width: 1180px) {
  .lower-nav__list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .lower-page-nav {
    top: 86px;
  }
}

@media (max-width: 860px) {
  .lower-breadcrumb,
  .lower-hero__inner,
  .lower-nav,
  .lower-page-nav,
  .lower-content,
  .lower-related,
  .lower-pager,
  .lower-back {
    width: min(100% - 28px, 720px);
  }

  .lower-hero__inner,
  .lower-media {
    grid-template-columns: 1fr;
  }

  .lower-hero__visual {
    order: -1;
    max-height: 420px;
  }

  .lower-page-nav {
    position: static;
    border-radius: 8px;
  }

  .lower-related__grid {
    grid-template-columns: 1fr;
  }

  .otter-3d-viewer-wrap {
    max-width: 100%;
    margin-top: 28px;
    padding: 10px;
    border-radius: 18px;
  }

  .otter-3d-viewer {
    height: 62vh;
    min-height: 420px;
    max-height: 560px;
    border-radius: 12px;
  }

  .otter-3d-loading {
    min-height: 300px;
    font-size: .85rem;
  }

  .otter-3d-caption {
    font-size: .9rem;
  }
}

@media (max-width: 560px) {
  .lower-hero {
    padding-top: 1rem;
  }

  .lower-hero__inner,
  .lower-nav,
  .lower-section,
  .lower-note {
    padding: 1rem;
  }

  .lower-hero__title {
    font-size: clamp(1.72rem, 9vw, 2.45rem);
  }

  .lower-hero__lead,
  .lower-section p,
  .lower-note p,
  .lower-card p {
    font-size: .96rem;
    line-height: 1.9;
  }

  .lower-nav__list,
  .lower-column,
  .lower-pager {
    grid-template-columns: 1fr;
  }

  .lower-nav {
    overflow: hidden;
  }

  .lower-nav__list {
    max-height: 56vh;
    overflow-y: auto;
    padding-right: .15rem;
  }

  .lower-nav__item {
    min-height: 48px;
  }

  .lower-page-nav {
    justify-content: flex-start;
    overflow-x: auto;
    flex-wrap: nowrap;
    padding: .6rem;
    -webkit-overflow-scrolling: touch;
  }

  .lower-page-nav a {
    flex: 0 0 auto;
    min-height: 44px;
  }

  .lower-pager__item--next {
    text-align: left;
  }
}