:root {
  --navy: #22313f;
  --navy-deep: #17212d;
  --teal: #2f95ad;
  --teal-soft: #d9edf1;
  --sand: #f5efe4;
  --sand-deep: #e5d8c2;
  --line: #d7dde3;
  --text: #273746;
  --muted: #65717c;
  /* Calcite light 既定値（未定義時のフォールバック） */
  --calcite-color-background: #f8f8f8;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "Noto Sans JP", "Hiragino Sans", "Yu Gothic", Meiryo, sans-serif;
  color: var(--text);
  background: none;
}

/* A-PLAT テンプレート内でもワイドレイアウトを維持（横幅は extra-parts.css の 1600px） */
body.seto-sea-page .l-container,
body.seto-sea-page .l-container__wrap {
  max-width: 1600px;
  width: 100%;
  margin-inline: auto;
}

/* ヘッダー分の余白が二重にならないようにする */
body.seto-sea-page .l-container {
  margin-top: 0;
}

body.seto-sea-page main#main {
  margin-top: 16px;
}

body.seto-sea-page section {
  margin-top: 0;
}

/* パンくずのマイナスマージン解除 */
body.seto-sea-page .c-bread__nav.-top {
  margin-inline: 0;
}

body.seto-sea-page .page-shell {
  width: 100%;
  max-width: 1600px;
  padding: 0;
  margin: 0 auto;
}

a {
  color: inherit;
}

button {
  font: inherit;
}

.page-shell {
  max-width: 1440px;
  width: calc(100vw - 32px);
  margin: 0 auto;
  padding: 12px 12px 20px;
}

.page-shell-wide {
  max-width: 1820px;
}

.shell-card {
  border: 1px solid rgba(198, 207, 214, 0.8);
  border-radius: 0;
  background: #f6f9fb;
  overflow: hidden;
}

.utility-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  padding: 20px;
  background: var(--navy);
  color: #fff;
}

.utility-title {
  max-width: 760px;
  font-size: 24px;
  font-weight: 700;
  line-height: 1.25;
}

.utility-brand {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 18px;
  flex-shrink: 0;
}

.brand-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 42px;
  padding: 6px 0;
}

.brand-link-static {
  cursor: default;
}


.brand-link img {
  display: block;
  max-height: 42px;
  width: auto;
  max-width: 190px;
}

.side-layout {
  display: grid;
  grid-template-columns: 360px minmax(0, 1fr);
  align-items: stretch;
  min-height: 880px;
  /* 左カラム（aside 幅）のみ従来のサンド系背景 */
  background: linear-gradient(180deg, #f8f4ed 0%, #f3ecde 100%) left top / 360px 100% no-repeat;
}

.side-layout-wide {
  grid-template-columns: 360px minmax(0, 1fr);
  background: linear-gradient(180deg, #f8f4ed 0%, #f3ecde 100%) left top / 360px 100% no-repeat;
}

.accordion-rail {
  background: linear-gradient(180deg, #f8f4ed 0%, #f3ecde 100%);
  border-right: 1px solid var(--sand-deep);
  align-self: stretch;
  height: auto;
  min-height: 100%;
}

.accordion-trigger {
  width: 100%;
  display: grid;
  grid-template-columns: 36px 1fr;
  align-items: center;
  gap: 12px;
  padding: 16px 18px;
  border: 0;
  background: transparent;
  text-align: left;
  color: #24313d;
  cursor: pointer;
}

.accordion-trigger:hover {
  background: rgba(47, 149, 173, 0.08);
}

.accordion-trigger.is-selected {
  background: rgba(255, 255, 255, 0.58);
}

.accordion-index {
  font-size: 38px;
  line-height: 1;
  font-weight: 300;
  color: #8b7a61;
}

.accordion-label {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  font-size: 20px;
  font-weight: 700;
  line-height: 1.4;
}

.flat-menu {
  display: grid;
}

.content-stage {
  min-height: 880px;
  height: auto;
  align-self: stretch;
}

.content-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  padding: 18px 24px 8px;
}

.content-title {
  margin: 0;
  font-size: 24px;
  line-height: 1.3;
}

.content-title:empty,
.content-caption:empty {
  display: none;
}

.content-caption {
  color: var(--muted);
  font-size: 13px;
  line-height: 1.6;
}

.content-view {
  display: none;
}

.content-view.is-active {
  display: block;
  min-height: 100%;
}

.water-toolbar {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
  padding: 16px 24px 12px;
}

.tab-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  padding: 0;
  flex: 1;
}

.tab-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 16px;
  border: 1px solid #9dbdcc;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.8);
  color: #355264;
  font-size: 14px;
  line-height: 1.2;
  font-weight: 700;
  cursor: pointer;
  transition: 160ms ease;
  text-decoration: none;
  text-align: center;
}

.tab-button:hover {
  border-color: #6aa3b7;
  color: #1c6e87;
}

.tab-button[aria-selected="true"] {
  background: linear-gradient(135deg, #298daa, #1b6e86);
  border-color: transparent;
  color: #fff;
}

.tab-button-external {
  flex-shrink: 0;
  border-color: #355264;
  background: #22313f;
  color: #fff;
}

.tab-button-external::after {
  content: "↗";
  font-size: 15px;
  line-height: 1;
}

.tab-button-external:hover {
  border-color: #22313f;
  color: #fff;
  background: #17212d;
}

.tab-button-external.is-disabled {
  border-color: #a3adb7;
  background: #c9d1d8;
  color: #6e7b86;
  cursor: not-allowed;
}

.tab-button-external.is-disabled::after {
  content: "";
}

.tab-panels {
  padding: 5px;
}

.tab-panel {
  display: block;
}

.dashboard-frame {
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 0;
  background: #fff;
}

.dashboard-frame iframe {
  display: block;
  width: 100%;
  height: 760px;
  border: 0;
  background: #fff;
}

.intro-frame-wrap {
  padding: 0;
  margin: 0;
  line-height: 0;
}

.intro-frame {
  display: block;
  width: 100%;
  height: 880px;
  min-height: 0;
  border: 0;
  border-radius: 0;
  background: #fff;
}

.placeholder-board {
  display: grid;
  gap: 18px;
  padding: 28px;
  border: 1px solid var(--line);
  border-radius: 0;
  background: #fff;
}

.section-placeholder,
.story-blocked-board,
.contact-board {
  margin: 24px;
}

.placeholder-board h3 {
  margin: 0;
  font-size: 24px;
}

.placeholder-board p {
  margin: 0;
  max-width: 760px;
  color: var(--muted);
  line-height: 1.8;
}

.contact-board p {
  max-width: none;
}

.inline-link {
  color: #1b6e86;
  font-weight: 700;
  text-decoration: none;
}

.inline-link:hover {
  text-decoration: underline;
}

.placeholder-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.placeholder-box {
  min-height: 220px;
  padding: 18px;
  border: 1px dashed #aebdca;
  border-radius: 20px;
  background: linear-gradient(135deg, rgba(47, 149, 173, 0.08), rgba(255, 255, 255, 0.9)), #fff;
}

.placeholder-box strong {
  display: block;
  margin-bottom: 8px;
  font-size: 18px;
}

.placeholder-box span {
  color: var(--muted);
  line-height: 1.7;
}

.tab-demo {
  margin-top: 8px;
}

.single-tabs {
  padding: 24px;
}

.single-tabs .tab-strip {
  padding: 0 0 18px;
}

.single-tabs .tab-panels {
  padding: 0;
}

.is-hidden {
  display: none;
}

@media (max-width: 1400px) {
  .side-layout-wide {
    grid-template-columns: 320px minmax(0, 1fr);
    background: linear-gradient(180deg, #f8f4ed 0%, #f3ecde 100%) left top / 320px 100% no-repeat;
  }

  .utility-title {
    max-width: 640px;
    font-size: 22px;
  }
}

@media (max-width: 960px) {
  .page-shell {
    width: calc(100vw - 16px);
    padding: 10px 8px 18px;
  }

  .side-layout,
  .side-layout-wide {
    grid-template-columns: 1fr;
    background: transparent;
  }

  .accordion-rail {
    border-right: 0;
    border-bottom: 1px solid var(--line);
    align-self: start;
    min-height: 0;
  }

  .content-stage {
    min-height: 720px;
  }

  .dashboard-frame iframe {
    height: 600px;
  }

  .intro-frame {
    height: 680px;
  }
}

@media (max-width: 640px) {
  .utility-bar,
  .content-head,
  .water-toolbar {
    flex-direction: column;
    align-items: flex-start;
  }

  .utility-title {
    max-width: none;
    font-size: 19px;
  }

  .utility-brand {
    gap: 12px;
  }

  .brand-link img {
    max-height: 34px;
    max-width: 150px;
  }

  .accordion-trigger {
    grid-template-columns: 22px 1fr;
    padding: 14px 16px;
  }

  .accordion-index {
    font-size: 28px;
  }

  .accordion-label {
    font-size: 16px;
  }

  .tab-button {
    width: 100%;
    text-align: center;
  }

  .tab-panels {
    padding-left: 16px;
    padding-right: 16px;
  }

  .placeholder-grid {
    grid-template-columns: 1fr;
  }

  .content-stage {
    min-height: 640px;
  }

  .dashboard-frame iframe {
    height: 560px;
  }

  .intro-frame {
    height: 656px;
  }
}

.seto-intro-page .main {
  min-height: 0;
  height: auto;
  padding: 10px 10px 12px;
}

.seto-intro-page .topbar {
  margin-bottom: 18px;
}

.seto-intro-page .summary {
  max-width: 900px;
}

.seto-intro-page .summary p {
  margin: 0;
  line-height: 1.9;
  color: #364856;
}

.seto-intro-page .tabbar {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0 0 0;
  padding: 8px 24px 8px;
  background: linear-gradient(180deg, rgba(249, 251, 252, 0.98) 0%, rgba(249, 251, 252, 0.94) 72%, rgba(249, 251, 252, 0) 100%);
  backdrop-filter: blur(6px);
}

.seto-intro-page .tabbar button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 16px;
  border: 1px solid #9dbdcc;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.9);
  color: #355264;
  font-size: 14px;
  line-height: 1.2;
  font-weight: 700;
  cursor: pointer;
  text-align: center;
}

.seto-intro-page .tabbar button[aria-selected="true"] {
  background: linear-gradient(135deg, #298daa, #1b6e86);
  border-color: transparent;
  color: #fff;
}

.seto-intro-page .panel {
  display: none;
  padding: 24px;
  border: 0;
  border-radius: 0;
  background: transparent;
}

.seto-intro-page .panel.is-active {
  display: block;
}

.seto-intro-page .panel h2 {
  margin: 0 0 13px;
  font-size: 28px;
  line-height: 1.25;
}

.seto-intro-page .panel p {
  margin: 0 0 14px;
  line-height: 1.9;
  color: #344655;
}

.seto-intro-page .lead-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 14px;
}

.seto-intro-page .lead-list li,
.seto-intro-page .caution-list li {
  padding: 14px 16px;
  border-radius: 16px;
  background: #f7fafb;
  border: 1px solid #e1e8ed;
  line-height: 1.8;
}

.seto-intro-page .inline-note {
  margin-top: 18px;
  padding: 14px 16px;
  border-radius: 16px;
  background: #eef6f8;
  color: #355264;
}

.seto-intro-page .grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
  margin-top: 18px;
}

.seto-intro-page .card {
  padding: 18px;
  border: 1px solid #dbe3e9;
  border-radius: 18px;
  background: linear-gradient(180deg, #ffffff, #f8fbfc);
}

.seto-intro-page .card h3 {
  margin: 0 0 10px;
  font-size: 18px;
  color: #14485a;
}


.seto-intro-page .card p {
  margin: 0;
}

.seto-intro-page .caution-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 14px;
}

.seto-intro-page .footer-note {
  margin-top: 20px;
  font-size: 13px;
  color: var(--muted);
}

.seto-intro-page .intro-stack {
  display: grid;
  gap: 18px;
  margin-top: 18px;
}

.seto-intro-page .info-block,
.seto-intro-page .map-block {
  padding: 18px;
  border: 1px solid #dbe3e9;
  border-radius: 20px;
  background: linear-gradient(180deg, #ffffff, #f8fbfc);
}

.seto-intro-page .info-block h3 {
  margin: 0 0 8px;
  font-size: 20px;
  color: #14485a;
}

.seto-intro-page .section-note {
  margin-bottom: 12px;
  color: #5a6a77;
}

.seto-intro-page .area-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.seto-intro-page .area-list li {
  padding: 8px 14px;
  border-radius: 999px;
  background: #eef6f8;
  border: 1px solid #d6e8ee;
  color: #20485a;
  line-height: 1.6;
}

.seto-intro-page .map-block {
  padding: 14px;
  background: linear-gradient(180deg, #f5fafb, #ffffff);
}

.seto-intro-page .map-embed {
  display: block;
  width: 100%;
  max-width: 920px;
  height: 600px;
  margin: 0 auto;
  border-radius: 14px;
  overflow: hidden;
}

.seto-intro-page .intro-list li {
  background: linear-gradient(180deg, #f7fafb, #ffffff);
}

@media (max-width: 760px) {
  .seto-intro-page .main {
    padding: 16px;
  }

  .seto-intro-page .tabbar {
    padding-left: 16px;
    padding-right: 16px;
  }

  .seto-intro-page .grid {
    grid-template-columns: 1fr;
  }

  .seto-intro-page .tabbar button {
    width: 100%;
  }

  .seto-intro-page .panel {
    padding: 16px;
  }

  .seto-intro-page .panel h2 {
    font-size: 24px;
  }

  .seto-intro-page .info-block,
  .seto-intro-page .map-block {
    padding: 16px;
  }

  .seto-intro-page .map-embed {
    height: 440px;
  }
}

@media (max-width: 480px) {
  .seto-intro-page .area-list li {
    width: 100%;
    text-align: center;
  }

  .seto-intro-page .overview-images {
    grid-template-columns: 1fr;
  }

  .seto-intro-page .map-embed {
    height: 360px;
  }
}

.seto-intro-page {
  min-height: 0;
  height: auto;
  background: #f6f9fb;
}

.seto-intro-page .map-block {
  padding: 0;
  border: 0;
  border-radius: 0;
  background: transparent;
}

.seto-intro-page .plain-block {
  margin: 18px 0;
  padding: 18px;
  border: 1px solid #dbe3e9;
  border-radius: 18px;
  background: #ffffff;
}

.seto-intro-page .plain-block h3 {
  margin: 0 0 10px;
  font-size: 20px;
  color: #14485a;
}

.seto-intro-page .plain-block p:last-child {
  margin-bottom: 0;
}

.seto-intro-page .overview-images {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
  margin: 20px 0;
}

.seto-intro-page .overview-images img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid #dbe3e9;
  border-radius: 18px;
  background: #ffffff;
  cursor: zoom-in;
}


.seto-intro-page .section-jump {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin: 4px 4px 4px 0;
  padding: 6px 12px;
  border: 1px solid #9dbdcc;
  border-radius: 999px;
  background: #eef6f8;
  color: #24556a;
  font: inherit;
  font-size: 13px;
  font-weight: 700;
  line-height: 1.4;
  cursor: pointer;
  vertical-align: middle;
}

.seto-intro-page .section-jump:hover {
  border-color: #6aa3b7;
  background: #e1f0f4;
}

.seto-intro-page .emphasis-red {
  color: #c4372f;
  font-weight: 700;
}

.seto-intro-page .plain-bullets {
  display: block;
  margin: 0 0 14px 1.2em;
  padding: 0;
  list-style: disc;
}

.seto-intro-page .plain-bullets li {
  margin: 0 0 10px;
  padding: 0;
  border: 0;
  border-radius: 0;
  background: transparent;
  line-height: 1.9;
}

.seto-intro-page .plain-bullets li:last-child {
  margin-bottom: 0;
}

.seto-intro-page .method-figure {
  margin: 20px auto;
  max-width: 760px;
}

.seto-intro-page .method-figure.is-wide {
  max-width: 980px;
}

.seto-intro-page .method-figure img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid #dbe3e9;
  border-radius: 18px;
  background: #ffffff;
}

.seto-intro-page .method-model-layout,
.seto-intro-page .method-conditions-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(280px, 34%);
  align-items: start;
  gap: 22px;
}

.seto-intro-page .method-model-copy .grid,
.seto-intro-page .method-conditions-copy .grid,
.seto-intro-page .method-conditions-copy .method-grid {
  grid-template-columns: 1fr;
}

.seto-intro-page .method-model-images,
.seto-intro-page .method-conditions-images {
  display: grid;
  gap: 14px;
  position: sticky;
  top: 12px;
}

.seto-intro-page .method-side-figure {
  margin: 0;
  max-width: none;
}

.seto-intro-page .method-side-figure img {
  border-radius: 14px;
}

.seto-intro-page .method-figure img {
  cursor: zoom-in;
}

.seto-intro-page .method-conditions-note {
  margin: 18px 0;
}

.seto-intro-page .method-conditions-note p {
  margin: 0;
}

.seto-intro-page .method-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
  margin-top: 18px;
}

.seto-intro-page .reference-list {
  margin: 0;
  padding-left: 1.4em;
  list-style: disc;
}

.seto-intro-page .reference-list li {
  margin-bottom: 12px;
  line-height: 1.8;
  color: #344655;
}

.seto-intro-page .reference-list a {
  color: #1b6e86;
  font-weight: 700;
}

.has-image-lightbox {
  overflow: hidden;
}

.image-lightbox[hidden] {
  display: none;
}

.image-lightbox {
  position: fixed;
  inset: 0;
  z-index: 1000;
  display: grid;
  place-items: center;
  padding: 28px;
}

.image-lightbox-backdrop {
  position: absolute;
  inset: 0;
  border: 0;
  background: rgba(10, 20, 28, 0.72);
  cursor: zoom-out;
}

.image-lightbox-panel {
  position: relative;
  z-index: 1;
  display: grid;
  gap: 10px;
  max-width: min(1120px, 96vw);
  max-height: 92vh;
}

.image-lightbox-panel img {
  display: block;
  max-width: 100%;
  max-height: calc(92vh - 54px);
  width: auto;
  height: auto;
  border-radius: 8px;
  background: #ffffff;
}

.image-lightbox-close {
  position: absolute;
  top: -14px;
  right: -14px;
  width: 38px;
  height: 38px;
  border: 1px solid rgba(255, 255, 255, 0.8);
  border-radius: 999px;
  background: #ffffff;
  color: #22313f;
  font-size: 26px;
  line-height: 1;
  cursor: pointer;
}

.image-lightbox-caption {
  margin: 0;
  padding: 8px 12px;
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.94);
  color: #22313f;
  font-size: 14px;
  line-height: 1.6;
}

@media (max-width: 760px) {
  .seto-intro-page .method-model-layout,
  .seto-intro-page .method-conditions-layout {
    grid-template-columns: 1fr;
  }

  .seto-intro-page .method-model-images,
  .seto-intro-page .method-conditions-images {
    position: static;
  }

  .seto-intro-page .method-grid {
    grid-template-columns: 1fr;
  }

  .image-lightbox {
    padding: 16px;
  }

  .image-lightbox-close {
    top: -10px;
    right: -10px;
  }
}


.site-footer {
  max-width: 1820px;
  margin: 2px auto 0;
  padding: 0 18px 14px;
  color: #4b5d6b;
  font-size: 14px;
  line-height: 1.8;
}

.site-footer p {
  margin: 0;
}

.site-footer a {
  color: #1b6e86;
  text-decoration: none;
}

.site-footer a:hover {
  text-decoration: underline;
}


.site-footer-links {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
}

.site-footer-separator {
  display: inline-flex;
  align-items: center;
}

/* ----------------------------------------
   シェル高さ：元の固定サイズ
---------------------------------------- */
body.seto-sea-page .side-layout,
body.seto-sea-page .side-layout-wide {
  display: grid;
  grid-template-columns: 360px minmax(0, 1fr);
  min-height: 880px;
  align-items: stretch;
  background: linear-gradient(180deg, #f8f4ed 0%, #f3ecde 100%) left top / 360px 100% no-repeat;
}

body.seto-sea-page .accordion-rail {
  background: linear-gradient(180deg, #f8f4ed 0%, #f3ecde 100%);
  align-self: stretch;
  min-height: 100%;
}

@media (max-width: 1400px) {
  body.seto-sea-page .side-layout,
  body.seto-sea-page .side-layout-wide {
    grid-template-columns: 320px minmax(0, 1fr);
    background: linear-gradient(180deg, #f8f4ed 0%, #f3ecde 100%) left top / 320px 100% no-repeat;
  }
}

@media (max-width: 960px) {
  body.seto-sea-page .side-layout,
  body.seto-sea-page .side-layout-wide {
    grid-template-columns: 1fr;
    background: transparent;
    min-height: 0;
  }

  body.seto-sea-page .accordion-rail {
    align-self: start;
    min-height: 0;
  }
}

body.seto-sea-page .content-stage {
  min-height: 880px;
}

body.seto-sea-page .intro-frame,
body.seto-sea-page .intro-frame.method-frame {
  display: block;
  width: 100%;
  height: 880px;
}

body.seto-sea-page .dashboard-frame {
  overflow: hidden;
}

body.seto-sea-page .dashboard-frame iframe {
  height: 760px;
}

@media (max-width: 960px) {
  body.seto-sea-page .content-stage {
    min-height: 720px;
  }

  body.seto-sea-page .dashboard-frame iframe {
    height: 600px;
  }

  body.seto-sea-page .intro-frame,
  body.seto-sea-page .intro-frame.method-frame {
    height: 680px;
  }
}

@media (max-width: 640px) {
  body.seto-sea-page .content-stage {
    min-height: 640px;
  }

  body.seto-sea-page .dashboard-frame iframe {
    height: 560px;
  }

  body.seto-sea-page .intro-frame,
  body.seto-sea-page .intro-frame.method-frame {
    height: 656px;
  }
}

.rich-text-body {
  background-color: var(--calcite-color-background);
}