/* =============================================================
   header / footer は既存サイト（/50th/）と同一体裁
   ブレークポイント 670px（既存サイトに準拠）
   ============================================================= */

:root {
  --primary: #005cac; 
  --primary-light: #0073b2;
  --gas: #22d0ad;
  --date: #333333;
  --text: #212121;
  --caption: #666666;
  --border: #d9d9d9;
  --featured-bg: #faf7eb;
  --site-blue: #023894;
  --site-copy-bg: #001943; 
  --site-gray: #666666;
  --fc-bg: #fcfcf2;
  --acc-duration: 400ms;
  --acc-easing: cubic-bezier(0.37, 0, 0.63, 1);

  --mobile-margin: calc(25 / 390 * 100%);
  --tablet-content-w: calc(100% - var(--mobile-margin) * 2);

  --content-w: min(1080px, var(--tablet-content-w));
  --inner-pad: 180px; 
  --site-inner: 980px; 

  --header-height: 100px;

  --serif: "Noto Serif JP", serif;
  --sans: "Noto Sans JP", sans-serif;
}

@media (max-width: 670px) {
  :root {
    --sp-scale: calc(100vw / 390);
    --header-height: calc(65px * var(--sp-scale));
    --mobile-margin: calc(25 / 390 * 100%);
    --content-w: calc(100% - var(--mobile-margin) * 2);
  }
}
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
body {
  font-family: var(--sans);
  color: var(--text);
  background: #fff;
  -webkit-font-smoothing: antialiased;
}

html,
body {
  overflow-x: clip;
}
#wrap,
.site {
  width: 100%;
}

a {
  text-decoration: none;
  color: inherit;
}
img {
  vertical-align: top;
  max-width: 100%;
}
ul {
  list-style: none;
}

.main {
  margin: 0 auto;
  background: #fff;
}

#pagetop img {
  z-index: 2;
}

/* =============================================================
   Site Header（既存サイト体裁）
   ============================================================= */
.site-header {
  border-bottom: 4px solid var(--site-blue);
  background: #fff;
}
.site-header__inner {
  max-width: 1240px;
  margin: 0 auto;
  padding: 12px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}
.site-header__logo img {
  max-height: 60px;
  width: auto;
}

.site-header__body {
  display: flex;
  align-items: center;
  gap: 20px;
}
.site-nav {
  display: flex;
  align-items: center;
}
.site-nav__item {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 0 12px;
  height: 50px;
  font-size: 14px;
  white-space: nowrap;
  color: #333;
  border-left: 1px solid #e3e3e3;
  transition: color 0.2s;
}
.site-nav__item:last-child {
  border-right: 1px solid #e3e3e3;
}
.site-nav__ico {
  width: 20px;
  height: auto;
}
.site-nav__item:hover {
  color: var(--site-blue);
}

.site-header__btns {
  display: flex;
  align-items: center;
  gap: 6px;
}
.site-header__btns img {
  height: 34px;
  width: auto;
  transition: opacity 0.2s;
}
.site-header__btns a:hover img {
  opacity: 0.8;
}

/* ハンバーガー（SP用・PCでは非表示） */
.site-header__toggle {
  display: none;
  width: 44px;
  height: 44px;
  border: none;
  background: var(--site-blue);
  border-radius: 4px;
  cursor: pointer;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
}
.site-header__toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: #fff;
  border-radius: 2px;
  transition:
    transform 0.3s,
    opacity 0.3s;
}

/* =============================================================
   Section: contents-header
   ============================================================= */
.contents-header {
  background: #fff;
  padding: 100px 0 40px;
  display: flex;
  flex-direction: column;
  align-items: center;
  border-bottom: 1px solid var(--primary);

  position: relative;
  z-index: 1;
}
@media (max-width: 1024px) {
  .contents-header {
    padding: 80px 0 40px;
  }
}
@media (max-width: 670px) {
  .contents-header {
    padding: 60px 0 16px;
    padding-top: 0;
    padding-top: calc(100vw * 40 / 390);
    padding-bottom: calc(100vw * 16 / 390);
  }
}
.contents-header-inner {
  width: var(--content-w);
  margin: 0 auto;
}
.contents-title-line {
  background: url(/images/60th/contents-title-line.svg) no-repeat center /
    contain;
  display: block;
  margin: 0 auto;
  width: 224px;
  height: 5px;
}
@media (max-width: 670px) {
  .contents-title-line {
    background: url(/images/60th/contents-title-line-sp.svg) no-repeat center /
      contain;
    display: block;
    margin: 0 auto;
    width: min(calc(100vw * 53 / 390), calc(53px * 1.5));
    height: min(calc(100vw * 4 / 390), calc(4px * 1.5));
  }
}

.contents-title {
  font-family: var(--serif);
  font-weight: 700;
  font-size: 60px;
  letter-spacing: 0.04em;
  color: var(--primary-light);
  text-align: center;
  margin: 0;
  margin-top: 16px;
  padding: 0;
  border: none;
}
@media (max-width: 1024px) {
  .contents-title {
    font-size: calc(60px * 0.8);
  }
}
@media (max-width: 670px) {
  .contents-title {
    font-size: 24px;
    font-size: calc(100vw * 24 / 390);
    margin-top: calc(100vw * 5 / 390);
  }
}

.tabs {
  background: #fff;
  display: flex;
  gap: 3px;
  justify-content: center;
  width: 100%;
  margin-top: 61px;
}
@media (max-width: 1024px) {
  .tabs {
    margin-top: 40px;
  }
}
@media (max-width: 670px) {
  .tabs {
    margin-top: 20px;
    margin-top: calc(100vw * 20 / 390);
    gap: 1px;
  }
}
.tab {
  flex: 1 0 0;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 18px 16px;
  font-weight: 700;
  font-size: 24px;
  color: var(--primary-light);
  background: #fff;
  border: 1px solid var(--primary-light);
  /* transition: background .1s, color .1s; */
}
@media (max-width: 1024px) {
  .tab {
    font-size: calc(24px * 0.8);
    padding-inline: 8px;
  }
}
@media (max-width: 670px) {
  .tab {
    font-size: min(calc(100vw * 16 / 390), calc(16px * 1.2));
    padding: 2px 8px;
  }
}

.tab:first-child {
  border-radius: 15px 0 0 0;
}
.tab:last-child {
  border-radius: 0 15px 0 0;
}

@media (max-width: 670px) {
  .tab:first-child {
    border-radius: 6px 0 0 0;
  }
  .tab:last-child {
    border-radius: 0 6px 0 0;
  }
}
.tab.is-active {
  background: var(--primary);
  border-color: var(--primary-light);
  color: #fff;
}
.tab:hover {
  background: var(--primary);
  border-color: var(--primary-light);
  color: #fff;
  text-decoration: none;
}

.contents-lead {
  margin-top: 59px;
  font-family: var(--serif);
  font-weight: 400;
  font-size: 40px;
  letter-spacing: 0.15em;
  color: var(--primary);
  text-align: center;
}
@media (max-width: 1024px) {
  .contents-lead {
    font-size: calc(40px * 0.8);
    margin-top: 40px;
  }
}
@media (max-width: 670px) {
  .contents-lead {
    font-size: 18px;
    font-size: calc(100vw * 18 / 390);
    margin-top: 20px;
    margin-top: calc(100vw * 20 / 390);
  }
}

/* =============================================================
   Section: Timeline
   ============================================================= */
.timeline {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 28px;
  padding-bottom: 48px;
}
.timeline::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  background:
    linear-gradient(
      180deg,
      rgba(255, 255, 255, 0.2) 0%,
      rgba(143, 218, 236, 0.2) 36%,
      rgba(88, 213, 205, 0.2) 63%,
      rgba(242, 240, 142, 0.2) 95%
    ),
    #fff;
}
.timeline-inner {
  width: var(--content-w);
  margin: 0 auto;
}

.timeline > .year:not(:first-child) {
  margin-top: 22px;
}

/* 通常イベント行 */
.event {
  width: 100%;
  background: #fff;
  display: flex;
  gap: 24px;
  align-items: flex-start;
  padding: 20px 50px 16px 100px;
  border-bottom: 1px solid var(--border);
}
@media (max-width: 670px) {
  .event {
    flex-direction: column;
    padding: 20px 4px 20px 15px;
  }
}

.event-tag {
  width: 140px;
  flex-shrink: 0;
}
.event-body {
  flex: 1 0 0;
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.event-date {
  font-weight: 700;
  font-size: 18px;
  color: var(--date);
}
.event-text {
  font-weight: 400;
  font-size: 14px;
  line-height: 1.8;
  color: var(--text);
}

/* タグ */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 4px 12px 4px 8px;
  border-radius: 4px;
  font-weight: 700;
  font-size: 12px;
  white-space: nowrap;
}
.tag::before {
  content: "";
  width: 20px;
  height: 20px;
  border-radius: 4px;
  flex-shrink: 0;
}
.tag-gas {
  background: rgba(34, 208, 173, 0.15);
  color: var(--gas);
}
.tag-gas::before {
  background: var(--gas);
}
.tag-td {
  background: rgba(0, 115, 178, 0.1);
  color: var(--primary);
}
.tag-td::before {
  background: var(--primary);
}

/* 注目イベント（カード） */
.featured {
  width: 782px;
  max-width: 100%;
  background: #fff;
  border-top: 2px solid var(--primary);
  border-radius: 0 0 8px 8px;
  /* padding: 24px 50px 40px; */
  padding-bottom: 40px;
  display: flex;
  flex-direction: column;
  gap: 0;
}

.featured:has(.tag-td) {
  border-top: 2px solid var(--primary);
}
.featured:has(.tag-gas) {
  border-top: 2px solid var(--gas);
}

.featured-top {
  margin-bottom: 30px;
}
.featured-details {
  display: block;
}
.featured-summary {
  padding-top: 24px;
  padding-inline: 50px;
  list-style: none;
  cursor: pointer;
}

@media (max-width: 670px) {
  .featured-summary {
    padding: 20px 15px 30px;
    padding-right: 0;
    padding-bottom: 0;
  }
}

.featured-summary:hover {
  opacity: 0.7;
}
.featured-summary::-webkit-details-marker {
  display: none;
}
.featured-summary::marker {
  content: "";
}
.featured-body {
  padding-inline: 50px;
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows var(--acc-duration) var(--acc-easing);
}

@media (max-width: 670px) {
  .featured-body {
    padding-inline: 15px;
  }
}
.featured-details.is-expanded .featured-body {
  grid-template-rows: 1fr;
}
.featured-body-inner {
  overflow: hidden;
  display: flex;
  flex-direction: column;
  gap: 30px;
  min-height: 0;
  padding-top: 0;
  transition: padding-top var(--acc-duration) var(--acc-easing);
}
.featured-details.is-expanded .featured-body-inner {
  padding-top: 30px;
}
.featured-details.is-expanded .featured-body-inner:has(.featured-title-desc) {
  padding-top: 0;
}
.featured-top {
  display: flex;
  align-items: center;
  gap: 16px;
}
.featured-date {
  font-weight: 700;
  font-size: 18px;
  color: var(--date);
}
.featured-title {
  font-weight: 700;
  font-size: 26px;
  line-height: 1.6;
  color: var(--text);
}
.featured-title .sub {
  font-weight: 500;
  font-size: 16px;
}
.featured-summary .opend-text {
  display: none;
  margin-top: 0;
  font-weight: 500;
  font-size: 16px;
  line-height: 1.6;
  color: var(--text);
}
.featured-details.is-expanded .featured-summary .opend-text {
  display: block;
}
.featured-lead {
  font-weight: 700;
  font-size: 20px;
  line-height: 1.5;
  color: var(--primary);
}
.featured-lead.gas {
  color: var(--gas);
}
.featured-desc {
  font-weight: 400;
  font-size: 14px;
  line-height: 2;
  color: var(--text);
}

.featured-media {
  display: flex;
  flex-direction: column;
  gap: 16px;
  padding-bottom: 70px;
}

.featured-media-opened {
  margin-top: 44px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}
.figs {
  display: flex;
  gap: 10px;
  background: #fff;
  width: fit-content;
  max-width: 100%;
}
.featured-media-opened .figs {
  display: flex;
  gap: 40px;
  width: fit-content;
  max-width: 100%;
}
.featured-media-opened .figs .fig {
  padding: 11px 12px;
}

@media (max-width: 670px) {
  .featured-media-opened .figs {
    gap: 20px;
  }
  .featured-media-opened .figs .fig {
    padding-left: 0;
  }
}
.fig {
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.fig .ph {
  width: 225px;
  height: 150px;
  background: repeating-linear-gradient(
    45deg,
    #e8e8e0 0 10px,
    #f0f0e8 10px 20px
  );
  display: block;
}
.fig-wide .ph {
  width: 254px;
  height: 169px;
}
.fig figcaption {
  font-size: 12px;
  color: var(--caption);
  line-height: 1.3;
}

.pdf-link .fig figcaption {
  width: 100%;
  display: flex;
  justify-content: space-between;
}

.pdf-link {
  align-self: flex-end;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  color: var(--caption);
}
@media (max-width: 670px) {
  .pdf-link {
    align-self: flex-start;
  }
}
a.pdf-link:hover {
  text-decoration: none;
}
.pdf-icon {
  background: url(/images/60th/ico_pdf.png) no-repeat center / contain;
  width: 16px;
  height: 16px;
  display: inline-block;
  vertical-align: middle;
  margin-left: 4px;
}

.featured .featured-toggle {
  align-self: center;
  width: 274px;
  max-width: 100%;
  height: 76px;
  margin-top: 30px;
  background: var(--fc-bg);
  border: 1px solid var(--border);
  border-radius: 4px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 11px;
  font-family: var(--sans);
  font-weight: 500;
  font-size: 16px;
  color: #000;
}
.featured .featured-toggle:hover {
  opacity: 0.7;
}
.featured .featured-toggle .featured-toggle-label-close {
  display: none;
}
.featured.is-open .featured-toggle .featured-toggle-label-open {
  display: none;
}
.featured.is-open .featured-toggle .featured-toggle-label-close {
  display: inline;
}
.featured .featured-toggle-arrow {
  width: 19px;
  height: 11px;
  background: url(/images/60th/icon_down.svg) no-repeat center / contain;
}
.featured.is-open .featured-toggle-arrow {
  background-image: url(/images/60th/icon_up.svg);
}

@media (prefers-reduced-motion: reduce) {
  .featured-body,
  .featured-body-inner {
    transition-duration: 0.01ms;
  }
}

.featured-title-desc {
  font-weight: 500;
  font-size: 16px;
  line-height: 1.6;
  color: var(--text);
}

/* =============================================================
   Section: Page Nav
   ============================================================= */
.page-nav {
  position: relative;
  z-index: 1;
  background: #fff;
  padding-top: 70px;
  padding-bottom: 70px;
}
.page-nav-inner {
  width: var(--content-w);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}
.page-nav-inner:not(:has(.btn-prev)) {
  justify-content: flex-end;
}
.btn-prev {
  width: min(444px, 48%);
  max-width: 100%;
  aspect-ratio: 444 / 124;
  background: var(--primary);
  border-radius: 13px;

  color: #fff;
  transition:
    background 0.2s,
    transform 0.2s;

  container-type: inline-size;
}

.nav-btn-inner {
  width: 100%;
  height: 100%;
  padding: 0 min(66px, calc(100cqw * 66 / 444));
  display: flex;
  flex-direction: row-reverse;
  align-items: center;
  justify-content: space-between;
  gap: min(33px, calc(100cqw * 33 / 444));
}
.btn-prev:hover {
  transform: translateX(-4px);
  text-decoration: none;
}
.btn-prev-labels {
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.btn-prev-main {
  font-weight: 700;
  font-size: min(31px, calc(100cqw * 31 / 444));
  line-height: 1.1;
  white-space: nowrap;
  text-align: center;
}
.btn-prev-sub {
  font-weight: 400;
  font-size: min(20px, calc(100cqw * 20 / 444));
  text-align: center;
}
.btn-prev-arrow {
  background: url(/images/60th/icon_next.svg) no-repeat center / contain;
  width: min(26px, calc(100cqw * 26 / 444));
  height: min(52px, calc(100cqw * 52 / 444));
  transform: scaleX(-1);
  flex-shrink: 0;
}
.btn-next {
  width: min(444px, 48%);
  max-width: 100%;
  aspect-ratio: 444 / 124;
  background: var(--primary);
  border-radius: 13px;

  color: #fff;
  transition:
    background 0.2s,
    transform 0.2s;

  container-type: inline-size;
}
.btn-next .nav-btn-inner {
  width: 100%;
  height: 100%;
  padding: 0 min(66px, calc(100cqw * 66 / 444));
  display: flex;
  flex-direction: row;
  align-items: center;
  justify-content: space-between;
  gap: min(33px, calc(100cqw * 33 / 444));
}
.btn-next:hover {
  transform: translateX(4px);
  text-decoration: none;
}
.btn-next-labels {
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.btn-next-main {
  font-weight: 700;
  font-size: min(31px, calc(100cqw * 31 / 444));
  line-height: 1.1;
  white-space: nowrap;
  text-align: center;
}
.btn-next-sub {
  font-weight: 400;
  font-size: min(20px, calc(100cqw * 20 / 444));
  text-align: center;
}
.btn-next-sub.text-sm {
  font-size: min(16px, calc(100cqw * 16 / 444));
}
.btn-next-arrow {
  background: url(/images/60th/icon_next.svg) no-repeat center / contain;
  width: min(26px, calc(100cqw * 26 / 444));
  height: min(52px, calc(100cqw * 52 / 444));
  flex-shrink: 0;
}

/* =============================================================
   Site Footer（既存サイト体裁）
   ============================================================= */
.site-footer {
  background: #fff;
}
.site-footer__inner {
  max-width: var(--site-inner);
  margin: 0 auto;
  padding: 25px 20px;
  text-align: center;
}
.site-footer__logo {
  font-size: 14px;
  color: #333;
  line-height: 1.6;
  margin-bottom: 28px;
}
.site-footer__logo img {
  display: inline-block;
  margin-bottom: 10px;
  max-height: 56px;
  width: auto;
}
.site-footer__nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
}
.site-footer__nav li {
  border-left: 1px solid var(--site-gray);
  line-height: 1;
}
.site-footer__nav li:first-child {
  border-left: none;
}
.site-footer__nav a {
  display: block;
  font-size: 12px;
  color: var(--site-gray);
  padding: 0 18px;
}
.site-footer__nav a:hover {
  text-decoration: underline;
}
.site-footer__copy {
  background: var(--site-copy-bg);
  color: #fff;
  text-align: center;
  padding: 20px;
}
.site-footer__copy p {
  font-size: 11px;
}

/* ページトップ */
.pagetop {
  position: fixed;
  right: 20px;
  bottom: 20px;
  width: 48px;
  height: 48px;
  background: var(--primary);
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transition:
    opacity 0.3s,
    visibility 0.3s;
  z-index: 50;
}
.pagetop.is-visible {
  opacity: 0.9;
  visibility: visible;
}
.pagetop:hover {
  opacity: 1;
}
.pagetop span {
  width: 12px;
  height: 12px;
  border-top: 2px solid #fff;
  border-right: 2px solid #fff;
  transform: rotate(-45deg);
  margin-top: 4px;
}

/* =============================================================
   レスポンシブ ── タブレット（671〜1100px）
   ============================================================= */

@media (max-width: 880px) {
  .site-header__body {
    gap: 16px;
  }
  .site-nav__item {
    padding: 0 10px;
    font-size: 13px;
  }
  .site-header__btns img {
    height: 32px;
  }
}

/* =============================================================
   レスポンシブ ── スマートフォン（≤670px）/ Figma node 340:3
   ============================================================= */
@media (max-width: 670px) {
  /* --- Header：ハンバーガー化 --- */
  .site-header__inner {
    padding: 10px 16px;
    position: relative;
  }
  .site-header__logo img {
    max-height: 44px;
  }
  .site-header__toggle {
    display: flex;
  }
  .site-header.is-open .site-header__toggle span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
  }
  .site-header.is-open .site-header__toggle span:nth-child(2) {
    opacity: 0;
  }
  .site-header.is-open .site-header__toggle span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
  }

  .site-header__body {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: #fff;
    border-bottom: 4px solid var(--site-blue);
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.1);
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.35s ease;
    z-index: 30;
  }
  .site-header.is-open .site-header__body {
    max-height: 520px;
  }
  .site-nav {
    flex-direction: column;
    align-items: stretch;
  }
  .site-nav__item {
    height: auto;
    padding: 16px 20px;
    border-left: none;
    border-bottom: 1px solid #eee;
    font-size: 15px;
  }
  .site-nav__item:last-child {
    border-right: none;
  }
  .site-header__btns {
    flex-wrap: wrap;
    justify-content: center;
    gap: 10px;
    padding: 16px 20px;
  }
  .site-header__btns img {
    height: 40px;
  }

  /* --- Timeline --- */
  .year {
    font-size: 56px;
    margin: 16px 0 8px 9px;
  }
  .timeline > .year:not(:first-child) {
    margin-top: 24px;
  }

  .event-tag {
    width: auto;
  }

  /* 注目イベント：全幅・縦積み */
  .featured {
    width: 100%;
    padding: 20px 15px 28px;
    padding: 0;
    padding-bottom: 40px;
    border-radius: 0 0 8px 8px;
  }
  .featured-top {
    gap: 12px;
    margin-bottom: 30px;
  }
  .featured-body-inner {
    gap: 30px;
  }
  .featured-details.is-expanded .featured-body-inner {
    padding-top: 0px;
  }
  .featured .featured-toggle {
    margin-top: 20px;
  }
  .featured-title .sub {
    font-size: 14px;
  }
  .featured-lead {
    font-size: 20px;
  }
  .figs {
    flex-direction: column;
    width: 100%;
  }
  .fig .ph,
  .fig-wide .ph {
    width: 100%;
    height: auto;
    aspect-ratio: 3 / 2;
  }
  .featured-toggle {
    width: 100%;
    height: 64px;
  }

  /* --- Page Nav --- */
  .page-nav {
    padding-top: 40px;
    padding-bottom: 40px;
  }
  .page-nav:not(:has(.btn-prev)) {
    justify-content: flex-end;
  }
  .btn-prev,
  .btn-next {
    width: calc(171px * 0.9);
    width: min(171px, calc(100cqw * 171 / 171));
    width: min(calc(100vw * 171 / 390), calc(171px * 1.2));
    max-width: 100%;
    aspect-ratio: 171 / 68;
    border-radius: calc(4 * var(--sp-scale));
  }
  .nav-btn-inner {
    width: 100%;
    height: 100%;
    padding: 0 min(9px, calc(100cqw * 9 / 171));
    display: flex;
    flex-direction: row-reverse;
    align-items: center;
    justify-content: center;
    gap: calc(100cqw * 9 / 171);
  }
  .btn-next .nav-btn-inner {
    width: 100%;
    height: 100%;
    padding: 0 min(66px, calc(100cqw * 66 / 444));
    display: flex;
    flex-direction: row;
    align-items: center;
    justify-content: center;
    gap: calc(100cqw * 33 / 444);
  }

  .btn-prev-sub,
  .btn-next-sub {
    font-size: calc(100cqw * 10 / 171);
  }
  .btn-prev-main,
  .btn-next-main {
    font-size: calc(100cqw * 14 / 171);
  }
  .btn-next-sub.text-sm {
    font-size: calc(100cqw * 12 / 171);
  }
  .btn-prev-arrow,
  .btn-next-arrow {
    background: url(/images/60th/icon_next.svg) no-repeat center / contain;
    width: calc(100cqw * 11 / 171);
    height: calc(100cqw * 23 / 171);
  }

  /* --- Footer --- */
  .site-footer__inner {
    padding: 15px 16px;
  }
  .site-footer__logo {
    font-size: 12px;
    margin-bottom: 20px;
  }
  .site-footer__logo img {
    max-height: 44px;
  }
  .site-footer__nav {
    flex-direction: row;
    flex-wrap: wrap;
    gap: 6px 0;
  }
  .site-footer__nav a {
    font-size: 11px;
    padding: 0 10px;
  }

  .pagetop {
    width: 40px;
    height: 40px;
    right: 12px;
    bottom: 12px;
  }
}

@media (max-width: 380px) {
  .mv-title {
    font-size: 36px;
  }
  .mv-lead {
    font-size: 18px;
  }
  .page-title {
    font-size: 22px;
  }
  .tab {
    font-size: 12px;
  }
}

.event-list {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 28px;
  margin-top: 28px;
}

.era-section + .era-section {
  margin-top: 78px;
}

.era-heading {
  font-family: var(--serif);
  font-weight: 800;
  font-size: 72px;
  color: var(--primary);
  line-height: calc(103 / 72);
  padding: 0;
  margin: 0;
  background: none;
  margin-top: 50px;
  margin-bottom: 28px;
}

figure {
  margin: 0;
}

img.history-img {
  width: 225px;
}
img.history-img-md {
  width: 254px;
}
img.history-img-lg {
  width: 277px;
}

.featured-innner {
  padding-top: 24px;
  padding-inline: 50px;
  padding-bottom: 15px;
}
@media (max-width: 670px) {
  .featured-innner {
    padding: 20px 4px 20px 15px;
  }
}

.sp-only {
  display: none;
}
@media (max-width: 670px) {
  .sp-only {
    display: block;
  }
  .pc-only {
    display: block;
  }
  @media (max-width: 670px) {
    .pc-only {
      display: none;
    }
  }

  .text-left-sp {
    text-align: left;
  }
  .text-center-sp {
    text-align: center;
  }
}

/* =============================================================
   MV / Hero
   ============================================================= */

@property --100vw {
  syntax: "<length>";
  inherits: true;
  initial-value: 0px;
}

@property --100vh {
  syntax: "<length>";
  inherits: true;
  initial-value: 0px;
}

@property --mv-base-w {
  syntax: "<number>";
  inherits: true;
  initial-value: 1440;
}

@property --mv-base-h {
  syntax: "<number>";
  inherits: true;
  initial-value: 897;
}

@property --mv-u {
  syntax: "<number>";
  inherits: true;
  initial-value: 1;
}

:root {
  --100vw: 100vw;
  --100vh: 100svh;
  --mv-base-w: 1440;
  --mv-base-h: 897;
  --mv-width-ratio: calc(var(--100vw) / (var(--mv-base-w) * 1px));
  --mv-height-ratio: max(calc(var(--100vh) / (var(--mv-base-h) * 1px)), 10/16);
  /* min: 16px基準で10px相当 / max: 基準の1.6倍 */
  --mv-u: clamp(
    calc(500 / 1128),
    min(calc(var(--mv-width-ratio)), calc(var(--mv-height-ratio))),
    5
  );
}

.mv {
  width: 100%;
  height: calc(100svh - var(--header-height));
  min-height: calc(775px * var(--mv-u));
  max-height: calc(100vw * 0.7);

  background: url(/images/60th/mv_bg_pc.png) no-repeat center top / cover;

  display: grid;
  grid-template-rows: auto auto auto 1fr auto;
  grid-template-rows: auto auto auto auto 1fr;
  --innner-left: calc(971px * var(--mv-u));
  --innner-right: calc(469px * var(--mv-u));
  grid-template-columns: minmax(0, 1fr) var(--innner-left) var(
      --innner-right
    ) minmax(0, 1fr);
  padding-top: calc(66px * var(--mv-u));

  position: sticky;
  top: 0;
  z-index: 1;
}

@media (max-width: 670px) {
  .mv {
    min-height: auto;
    height: calc(1009 * var(--sp-scale));

    max-height: none;
    background: url(/images/60th/mv_bg_sp.png) no-repeat center top / cover;

    grid-template-columns: minmax(0, 1fr) var(--content-w) minmax(0, 1fr);
    padding-top: 0;

    position: relative;
  }
}

.mv.--lower {
  background: url(/images/60th/mv_bg_pc_lower.png) no-repeat center top / cover;

  min-height: auto;
  max-height: none;
  height: auto;
  aspect-ratio: 1440/675;
  padding-top: calc(100vw * 222 / 1440);
  --innner-left: calc(971px * var(--mv-width-ratio));
  --innner-right: calc(469px * var(--mv-width-ratio));
  grid-template-columns: minmax(0, 1fr) var(--innner-left) var(
      --innner-right
    ) minmax(0, 1fr);
}

@media (max-width: 670px) {
  .mv.--lower {
    padding-top: 0;
    background: url(/images/60th/mv_bg_sp.png) no-repeat center top / cover;
    grid-template-columns: minmax(0, 1fr) var(--content-w) minmax(0, 1fr);
  }
}

.mv-title {
  grid-column: 2;
  padding: 0;
  margin: 0;
  background: none;
  text-align: left;
  width: fit-content;
  max-width: none;
  width: 100%;
  container-type: inline-size;

  padding-left: calc(117px * var(--mv-u));
  padding-right: calc(44px * var(--mv-u));
}

@media (max-width: 670px) {
  .mv-title {
    padding-inline: 0;
    justify-self: center;
    align-self: center;
    text-align: center;
    padding-inline: 0;
    transform: translateX(calc(100cqw * 10 / 340));
  }
}

.mv.--lower .mv-title {
  padding-left: calc(117px * var(--mv-width-ratio));
  padding-right: calc(44px * var(--mv-width-ratio));
}
@media (max-width: 670px) {
  .mv.--lower .mv-title {
    padding-inline: 0;
  }
}

.mv-title-text {
  font-family: var(--serif);
  font-weight: 500;
  font-size: calc(100cqw * 75 / 810);
  white-space: nowrap;
  color: #000;
  line-height: calc(108 / 75);
}
@media (max-width: 670px) {
  .mv-title-text {
    font-size: calc(100cqw * 50 / 340);
  }
}
.mv-title-num {
  font-size: calc(100cqw * 96 / 810);
  line-height: calc(138 / 96);
  letter-spacing: -0.05em;
}
@media (max-width: 670px) {
  .mv-title-num {
    font-size: calc(100cqw * 65 / 340);
  }
}

.mv-title-center {
  margin-left: -0.2em;
}
.mv-title-right {
  margin-left: -0.8em;
}
@media (max-width: 670px) {
  .mv-title-right {
    margin-left: 0;
  }
}

.mv-sub-title {
  grid-column: 2;
  padding: 0;
  margin: 0;
  background: none;
  text-align: left;
  width: 100%;
  container-type: inline-size;
  padding-left: calc(308px * var(--mv-u));
  padding-right: calc(44px * var(--mv-u));
  margin-top: calc(12px * var(--mv-u) * -1);
}

@media (max-width: 670px) {
  .mv-sub-title {
    padding-inline: 0;
    justify-self: center;
    align-self: center;
    text-align: center;
    margin-top: calc(100cqw * 10 / 340);
  }
}
.mv-sub-title span {
  color: var(--primary);
  font-family: var(--serif);
  font-weight: 400;
  font-size: calc(100cqw * 32 / 613);
  line-height: calc(46 / 32);
}
@media (max-width: 670px) {
  .mv-sub-title span {
    font-size: calc(100cqw * 16 / 340);
  }
}

.mv.--lower .mv-sub-title {
  padding-left: calc(308px * var(--mv-width-ratio));
  padding-right: calc(44px * var(--mv-width-ratio));
  margin-top: calc(12px * var(--mv-width-ratio) * -1);
}

@media (max-width: 670px) {
  .mv.--lower .mv-sub-title {
    padding-inline: 0;
    margin-top: calc(100cqw * 10 / 340);
  }
}
.mv-line-img {
  grid-column: 1/3;
  width: 100%;
  height: calc(5px * var(--mv-u));
  max-height: calc(5px * 1.2);
  object-fit: cover;
  object-position: left center;
  margin-top: calc(29px * var(--mv-u));
}
@media (max-width: 670px) {
  .mv-line-img {
    object-position: right center;
    margin-top: calc(100vw * 10 / 390);
  }
}

.mv.--lower .mv-line-img {
  margin-top: calc(29px * var(--mv-width-ratio));
  height: calc(5px * var(--mv-width-ratio));
}

.mv-logo-img {
  grid-row: 1/5;
  grid-column: 3;
  width: calc(226px * var(--mv-u));
  margin-top: calc(75px * var(--mv-u));
  margin-left: calc(48px * var(--mv-u));
}
@media (max-width: 670px) {
  .mv-logo-img {
    grid-row: 1;
    grid-column: 2;
    width: calc(115 * var(--sp-scale));
    margin-inline: 0;
    margin-top: calc(53 * var(--sp-scale));

    justify-self: center;
  }
}

.mv.--lower .mv-logo-img {
  width: calc(100vw * 226 / 1440);
  margin-top: calc(100vw * 22 / 1440);
  margin-left: calc(100vw * 42 / 1440);
}

@media (max-width: 670px) {
  .mv.--lower .mv-logo-img {
    width: calc(115 * var(--sp-scale));
    margin-inline: 0;
    margin-top: calc(59 * var(--sp-scale));
  }
}

.mv-text-wrap {
  grid-column: 2;
  width: 100%;
  height: fit-content;
  container-type: inline-size;
  padding: 0;
  margin: 0;
  background: none;
  text-align: left;
  padding-left: calc(226px * var(--mv-u));
  padding-right: calc(31px * var(--mv-u));
  margin-top: calc(21px * var(--mv-u));
}
@media (max-width: 670px) {
  .mv-text-wrap {
    padding-inline: 0;
    justify-self: center;
    align-self: start;
    text-align: left;
    margin-top: calc(100cqw * 20 / 340);
  }
}
.mv-text {
  color: #000;
  font-family: var(--serif);
  font-weight: 400;
  font-size: calc(100cqw * 16 / 706);
  line-height: calc(39 / 16);
  letter-spacing: 0.04em;
}
@media (max-width: 670px) {
  .mv-text {
    font-size: calc(100cqw * 15 / 340);
    line-height: calc(28 / 15);
  }
}

.mv-text-sign {
  margin-top: calc(15px * var(--mv-u));
  margin-right: calc(44px * var(--mv-u));
  text-align: right;
}

@media (max-width: 670px) {
  .mv-text-sign {
    margin-top: calc(100cqw * 20 / 340);
    margin-right: 0;
    text-align: right;
  }
}
.scroll-cue {
  grid-column: 2/4;
  justify-self: center;
  align-self: end;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: calc(8px * var(--mv-u));
  z-index: 6;
  color: #000;
  opacity: 0.9;
  visibility: visible;
  transition:
    opacity 0.3s,
    visibility 0.3s;
}

@media (max-width: 670px) {
  .scroll-cue {
    grid-column: 2;
    margin-top: calc(100cqw * 20 / 340);
  }
}

@media (max-width: 670px) {
  .mv.--lower .scroll-cue {
    margin-top: calc(100vw * 80 / 390);
  }
}

.scroll-cue.is-hidden {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}
@media (max-width: 670px) {
  .scroll-cue,
  .scroll-cue.is-hidden {
    opacity: 0.9;
    visibility: visible;
    pointer-events: auto;
    transition: none;
  }
}
.scroll-cue:hover {
  opacity: 1;
  text-decoration: none;
}
.scroll-cue span:first-child {
  font-family: var(--serif);
  font-weight: 500;
  font-size: calc(15px * var(--mv-u));
  letter-spacing: 0.12em;
}
@media (max-width: 670px) {
  .scroll-cue span:first-child {
    font-size: calc(100vw * 15 / 390);
  }
}

.scroll-arrow {
  width: calc(49px * var(--mv-u));
  height: calc(59px * var(--mv-u));

  background: url(/images/60th/scroll-arrow.svg) no-repeat center top / contain;
  animation: scrollMove 1.8s infinite;
  opacity: 0.8;
}
@media (max-width: 670px) {
  .scroll-arrow {
    width: calc(100vw * 48 / 390);
    height: calc(100vw * 48 / 390);
  }
}

@keyframes scrollMove {
  0% {
    opacity: 0.8;
    transform: translateY(0);
  }
  100% {
    opacity: 0;
    transform: translateY(calc(24px * var(--mv-u)));
  }
}
@media (max-width: 670px) {
  @keyframes scrollMove {
    0% {
      opacity: 0.8;
      transform: translateY(0);
    }
    100% {
      opacity: 0;
      transform: translateY(calc(100vw * 24 / 390));
    }
  }
}