:root {
  --coral: #e85465;
  --coral-dark: #d94559;
  --soft-pink: #fdebed;
  --header-blue: #9fb4d8;
  --text: #333333;
  --content-width: 1281px;
  --inner-width: 980px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--text);
  background: #ffffff;
  font-family: "Noto Sans JP", "Yu Gothic", "Hiragino Kaku Gothic ProN", Meiryo, sans-serif;
  -webkit-font-smoothing: antialiased;
}

img {
  display: block;
  max-width: 100%;
  height: auto;
}

.site-header {
  position: relative;
  padding: 58px 20px 20px;
  background: var(--header-blue);
}

.header-inner {
  width: 100%;
  max-width: 980px;
  margin: 0 auto;
}

.back-link {
  position: absolute;
  top: 0;
  left: 0;
  width: 250px;
  margin: 0;
  display: block;
}

.back-link:hover,
.back-link:focus-visible {
  opacity: 0.82;
}

.back-link img {
  width: 100%;
  height: auto;
}

.language-nav {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  width: min(100%, 760px);
  margin: 0 auto;
  border: 1px solid rgba(255, 255, 255, 0.7);
  background: rgba(255, 255, 255, 0.9);
}

.language-nav a {
  display: flex;
  min-height: 38px;
  align-items: center;
  justify-content: center;
  padding: 8px 10px;
  border-right: 1px solid #dadada;
  color: #333333;
  font-size: 13px;
  font-weight: 700;
  line-height: 1.2;
  text-decoration: none;
  transition: background-color 0.2s ease, color 0.2s ease;
}

.language-nav a:last-child {
  border-right: 0;
}

.language-nav a:hover,
.language-nav a:focus-visible {
  background: #fff5f6;
}

.language-nav .is-active {
  color: #ffffff;
  background: var(--coral);
}

.hero {
  overflow: hidden;
  /*background: #ffffff;*/
  background: var(--header-blue);
}

.hero-visual,
.period-band img {
  width: min(100%, var(--content-width));
  margin: 0 auto;
}

.period-band {
  position: relative;
  z-index: 2;
  margin-top: max(-55px, -4.3vw);
  background: transparent;
  /*background: var(--coral);*/
}

.decorative-section {
  position: relative;
  overflow: hidden;
}

.content-shell {
  position: relative;
  z-index: 1;
  width: min(calc(100% - 40px), var(--inner-width));
  margin: 0 auto;
}

.content-shell--wide {
  width: min(calc(100% - 40px), 1180px);
}

.intro-section {
  padding: clamp(72px, 7vw, 100px) 0 clamp(80px, 7vw, 105px);
  background: #ffffff;
}

.intro-copy {
  width: min(100%, 583px);
  margin: 0 auto;
}

.future-diagram {
  width: min(100%, 549px);
  margin: clamp(52px, 5vw, 72px) auto 0;
}

.detail-section {
  padding: clamp(64px, 6vw, 82px) 0 clamp(78px, 7vw, 100px);
  background: #ffffff;
}


.section-title {
  width: min(100%, 634px);
  margin: 0 auto clamp(28px, 3vw, 40px);
}

.detail-panel,
.area-panel {
  width: 100%;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding: clamp(24px, 3vw, 38px) 20px clamp(42px, 4vw, 58px);
}

#overview {
  padding-top: clamp(48px, 5vw, 70px);
  padding-bottom: 0;
  background: #ffffff;
}

#overview .section-title {
  margin: 0 auto;
}

/* 実施内容もタイトルと本文をDOMで分け、背景境界のズレを防ぐ */
#overview .detail-panel {
  width: 100%;
  margin-top: 0;
  padding: clamp(28px, 3vw, 42px) 20px clamp(58px, 5vw, 78px);
  background: var(--soft-pink);
}

.implementation-detail {
  width: min(100%, 428px);
}

.lane-diagram {
  width: min(100%, 597px);
  margin: 0 auto;
}

#lane {
  padding-bottom: clamp(78px, 7vw, 100px);
}

#lane .section-title {
  margin-bottom: clamp(30px, 3vw, 42px);
}

#area {
  padding-top: clamp(48px, 5vw, 66px);
  padding-bottom: 0;
  background: #ffffff;
}

#area .section-title {
  margin: 0 auto;
}

/* 背景色を画像の高さではなくDOMに持たせるため、画面幅が変わっても境界がズレない */
#area .area-panel {
  width: 100%;
  margin-top: 0;
  padding: clamp(28px, 3vw, 42px) 20px clamp(72px, 6vw, 90px);
  background: var(--soft-pink);
}

.area-map {
  width: min(100%, 642px);
  margin: 0 auto;
}

.heart-cluster {
  position: absolute;
  z-index: 0;
  width: 92px;
  height: 92px;
  pointer-events: none;
  opacity: 0.62;
}

.heart-cluster--left {
  left: max(5vw, 40px);
  top: 160px;
}

.heart-cluster--right {
  right: max(5vw, 40px);
  top: 160px;
  transform: scaleX(-1);
}

.heart-cluster--upper {
  top: 80px;
}

.heart-cluster span {
  position: absolute;
  color: #f7a3ae;
  font-size: 23px;
  line-height: 1;
  transform: rotate(-14deg);
}

.heart-cluster span:nth-child(1) {
  left: 10px;
  top: 3px;
  color: #ee788a;
  font-size: 18px;
}

.heart-cluster span:nth-child(2) {
  left: 38px;
  top: 16px;
  color: #ffd18b;
  font-size: 20px;
}

.heart-cluster span:nth-child(3) {
  left: 4px;
  top: 35px;
  color: #f39cad;
  font-size: 20px;
}

.heart-cluster span:nth-child(4) {
  left: 34px;
  top: 47px;
  color: #f6c0c8;
  font-size: 18px;
}

.heart-cluster span:nth-child(5) {
  left: 62px;
  top: 62px;
  color: #f4b5c0;
  font-size: 15px;
}

.site-footer {
  padding-top: clamp(62px, 6vw, 82px);
  background: #ffffff;
}

.footer-logos {
  display: flex;
  justify-content: center;
  padding-bottom: 30px;
}

.footer-wave {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  min-height: 100px;
  padding: 20px;
  color: #ffffff;
  background-color: #e85465;
  font-family: Arial, Helvetica, sans-serif;
  font-size: 12px;
  font-weight: 400;
  line-height: 1.5;
  letter-spacing: 0.18em;
  text-align: center;
}

.red_line {
  border: solid 2px #DD0000
}
.contact {
  padding-top: 1em;
  text-align: center;
  font-size: 18px;
  line-height: 2em;
  letter-spacing: 0.1em;
}

@media (max-width: 900px) {
  .site-header {
    
  }

  .back-link {
    width: 230px;
  }

  .back-link img {
    width: 100%;
    height: auto;
  }

  /* 言語切り替えを中央配置 */
  .language-nav {
    width: min(100%, 760px);
    margin: 0 auto;
  }

  .language-nav a {
    min-height: 34px;
    padding: 7px 5px;
    font-size: 11px;
  }

  .intro-section {
    padding: 68px 0 82px;
  }

  .future-diagram {
    margin-top: 50px;
  }

  .detail-section {
    padding: 58px 0 74px;
  }


  .section-title {
    margin-bottom: 30px;
  }

  .detail-panel,
  .area-panel {
    padding: 24px 10px 42px;
  }

  #overview {
    padding-top: 48px;
  }

  #overview .detail-panel {
    padding: 24px 16px 62px;
  }

  #lane .section-title {
    margin-bottom: 30px;
  }

  #area {
    padding-top: 46px;
  }

  #area .area-panel {
    padding: 24px 16px 64px;
  }

  .heart-cluster--left {
    left: 18px;
  }

  .heart-cluster--right {
    right: 18px;
  }

  .heart-cluster {
    transform: scale(0.82);
    transform-origin: center;
  }

  .heart-cluster--right {
    transform: scale(-0.82, 0.82);
  }

  .site-footer {
    padding-top: 54px;
  }

  .footer-logos {

  }
}

@media (max-width: 560px) {
  .site-header {
    
  }

  .back-link {
    width: 210px;
  }

  .language-nav {
    width: 100%;
  }

  .language-nav a {
    border-bottom: 1px solid #dadada;
  }

  .language-nav a:nth-child(3) {
    border-right: 0;
  }

  .language-nav a:nth-child(n + 4) {
    border-bottom: 0;
  }

  .language-nav a:last-child {
    border-right: 1px solid #dadada;
  }

  .content-shell,
  .content-shell--wide {
    width: min(calc(100% - 28px), 1180px);
  }

  .intro-section {
    padding: 46px 0 60px;
  }

  .future-diagram {
    margin-top: 36px;
  }

  .detail-section {
    padding: 42px 0 56px;
  }


  .section-title {
    margin-bottom: 22px;
  }

  .detail-panel,
  .area-panel {
    padding: 16px 2px 30px;
  }

  #overview {
    padding-top: 34px;
  }

  #overview .detail-panel {
    padding: 18px 14px 46px;
  }

  #lane .section-title {
    margin-bottom: 22px;
  }

  #area {
    padding-top: 34px;
  }

  #area .area-panel {
    padding: 18px 14px 46px;
  }

  .heart-cluster {
    display: none;
  }

  .site-footer {
    padding-top: 40px;
  }

  .footer-logos {

  }

  .footer-wave {
    min-height: 72px;
    padding: 16px 10px;
    font-size: 9px;
    letter-spacing: 0.1em;
    white-space: nowrap;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
  }
}