:root {
  --bg: #0d1119;
  --bg-soft: #121826;
  --surface: rgba(16, 24, 38, 0.88);
  --surface-soft: rgba(255, 255, 255, 0.05);
  --line: rgba(255, 255, 255, 0.12);
  --text: #f5f7fb;
  --muted: rgba(245, 247, 251, 0.72);
  --accent: #9fb2ff;
  --accent-strong: #d7b8ff;
  --shadow: 0 24px 70px rgba(0, 0, 0, 0.34);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--text);
  font-family: "Inter", "Noto Sans JP", "Hiragino Sans", sans-serif;
  background:
    radial-gradient(circle at top left, rgba(159, 178, 255, 0.16), transparent 30%),
    radial-gradient(circle at top right, rgba(215, 184, 255, 0.12), transparent 32%),
    linear-gradient(180deg, #090d15 0%, #0c1119 100%);
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background:
    linear-gradient(rgba(255, 255, 255, 0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.03) 1px, transparent 1px);
  background-size: 28px 28px;
  mask-image: radial-gradient(circle at center, black 36%, transparent 86%);
}

.prologue-particles {
  position: fixed;
  inset: 0;
  pointer-events: none;
  overflow: hidden;
  z-index: 0;
}

.prologue-particles__dot {
  position: absolute;
  bottom: -32px;
  width: 5px;
  height: 5px;
  border-radius: 999px;
  background: radial-gradient(circle, rgba(255, 248, 252, 0.96) 0%, rgba(255, 170, 215, 0.76) 38%, rgba(255, 120, 196, 0.36) 62%, rgba(255, 120, 196, 0) 100%);
  opacity: 0;
  filter: blur(0.6px);
  box-shadow:
    0 0 10px rgba(255, 154, 213, 0.42),
    0 0 18px rgba(255, 112, 189, 0.24);
  animation: prologueParticleFloat 14s linear infinite;
}

.prologue-particles__dot:nth-child(1) { left: 4%; animation-delay: 0s; animation-duration: 13s; }
.prologue-particles__dot:nth-child(2) { left: 10%; animation-delay: 1.2s; animation-duration: 16s; }
.prologue-particles__dot:nth-child(3) { left: 16%; animation-delay: 3.2s; animation-duration: 15s; }
.prologue-particles__dot:nth-child(4) { left: 22%; animation-delay: 0.9s; animation-duration: 17s; }
.prologue-particles__dot:nth-child(5) { left: 29%; animation-delay: 4.1s; animation-duration: 14s; }
.prologue-particles__dot:nth-child(6) { left: 35%; animation-delay: 2.4s; animation-duration: 18s; }
.prologue-particles__dot:nth-child(7) { left: 42%; animation-delay: 5.2s; animation-duration: 15s; }
.prologue-particles__dot:nth-child(8) { left: 48%; animation-delay: 1.2s; animation-duration: 16s; }
.prologue-particles__dot:nth-child(9) { left: 54%; animation-delay: 3.8s; animation-duration: 14s; }
.prologue-particles__dot:nth-child(10) { left: 61%; animation-delay: 2.1s; animation-duration: 17s; }
.prologue-particles__dot:nth-child(11) { left: 67%; animation-delay: 4.7s; animation-duration: 15s; }
.prologue-particles__dot:nth-child(12) { left: 73%; animation-delay: 1.4s; animation-duration: 16s; }
.prologue-particles__dot:nth-child(13) { left: 79%; animation-delay: 2.8s; animation-duration: 15s; }
.prologue-particles__dot:nth-child(14) { left: 84%; animation-delay: 5.5s; animation-duration: 18s; }
.prologue-particles__dot:nth-child(15) { left: 88%; animation-delay: 0.7s; animation-duration: 14s; }
.prologue-particles__dot:nth-child(16) { left: 92%; animation-delay: 3.6s; animation-duration: 17s; }
.prologue-particles__dot:nth-child(17) { left: 95%; animation-delay: 1.9s; animation-duration: 15s; }
.prologue-particles__dot:nth-child(18) { left: 98%; animation-delay: 4.4s; animation-duration: 16s; }

@keyframes prologueParticleFloat {
  0% {
    transform: translate3d(0, 0, 0) scale(0.8);
    opacity: 0;
  }
  12% {
    opacity: 0.45;
  }
  50% {
    transform: translate3d(10px, -42vh, 0) scale(1);
    opacity: 0.5;
  }
  100% {
    transform: translate3d(-8px, -92vh, 0) scale(0.88);
    opacity: 0;
  }
}

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

.prologue-page {
  position: relative;
  z-index: 1;
  min-height: 100vh;
}

.prologue-header {
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  background: rgba(6, 10, 18, 0.74);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.prologue-header__inner,
.prologue-hero__inner,
.prologue-intro__inner,
.prologue-scenes__inner {
  width: min(1160px, calc(100% - 40px));
  margin: 0 auto;
}

.prologue-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 18px 0;
}

.scene-card__eyebrow {
  margin: 0 0 6px;
  font-size: 0.74rem;
  letter-spacing: 0.3em;
  text-transform: uppercase;
  color: var(--accent-strong);
}

.prologue-header__title {
  margin: 0;
  display: flex;
  align-items: baseline;
  gap: 10px;
  flex-wrap: wrap;
  font-family: "Times New Roman", "Yu Mincho", serif;
}

.prologue-header__title-main {
  font-size: clamp(1.35rem, 2vw, 2rem);
  letter-spacing: 0.12em;
}

.prologue-header__title-sub {
  font-size: clamp(0.92rem, 1.2vw, 1.08rem);
  letter-spacing: 0.28em;
  color: var(--muted);
}

.prologue-nav {
  display: flex;
  gap: 18px;
  flex-wrap: nowrap;
  justify-content: flex-end;
  align-items: center;
}

.prologue-nav a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 0;
  padding: 0;
  color: rgba(245, 247, 251, 0.88);
  text-decoration: none;
  font-size: 0.84rem;
  letter-spacing: 0.18em;
  border: 0;
  background: transparent;
  transition: color 0.28s ease, opacity 0.28s ease;
}

.prologue-nav a:hover,
.prologue-nav a:focus-visible {
  color: #ffffff;
  opacity: 1;
}

.prologue-hero {
  position: relative;
  padding: 48px 0 28px;
  overflow: hidden;
}

.prologue-hero__bg {
  position: absolute;
  inset: 0;
  background: url("../image/mv_bg.jpg") center top / cover no-repeat;
  opacity: 0.34;
  transform: translate3d(0, 0, 0) scale(1.06);
  will-change: transform;
}

.prologue-hero__inner {
  position: relative;
  z-index: 1;
}

.prologue-hero__visual-wrap {
  position: relative;
  overflow: hidden;
  border-radius: 22px;
  border: 1px solid rgba(255, 255, 255, 0.1);
  background: rgba(255, 255, 255, 0.03);
  box-shadow: var(--shadow);
}

.prologue-hero__visual-wrap::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.05), transparent 24%, rgba(0, 0, 0, 0.2));
  pointer-events: none;
}

.prologue-hero__visual {
  width: 100%;
}

.prologue-intro {
  padding: 18px 0 70px;
}

.prologue-intro__heading-wrap {
  width: min(1160px, calc(100% - 40px));
  margin: 0 auto 22px;
}

.prologue-intro__heading {
  margin: 0;
  padding: 18px 24px;
  text-align: center;
  font-family: "Times New Roman", "Yu Mincho", serif;
  font-size: clamp(1.35rem, 2vw, 2rem);
  letter-spacing: 0.12em;
  color: rgba(245, 247, 251, 0.92);
  background: linear-gradient(135deg, rgba(159, 178, 255, 0.16), rgba(215, 184, 255, 0.2));
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 18px;
  box-shadow: 0 14px 34px rgba(0, 0, 0, 0.2);
}

.prologue-intro__inner {
  width: min(1160px, calc(100% - 40px));
  max-width: none;
}

.prologue-intro__inner p {
  margin: 0 0 24px;
  font-size: clamp(1rem, 1.55vw, 1.18rem);
  line-height: 2.2;
  color: rgba(245, 247, 251, 0.88);
}

.prologue-intro__note {
  width: 100%;
  margin-top: 30px;
  padding: 28px 30px;
  border-radius: 20px;
  border: 1px solid rgba(255, 255, 255, 0.1);
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.05), rgba(255, 255, 255, 0.02));
  box-shadow: 0 14px 36px rgba(0, 0, 0, 0.18);
}

.prologue-intro__note p {
  margin: 0 0 18px;
  font-size: clamp(0.96rem, 1.38vw, 1.08rem);
  line-height: 2.05;
  color: rgba(255, 244, 250, 0.9);
  text-shadow:
    0 0 1px rgba(255, 205, 232, 0.85),
    0 0 6px rgba(255, 132, 198, 0.32),
    0 0 14px rgba(255, 112, 189, 0.16);
}

.prologue-intro__note p:last-child {
  margin-bottom: 0;
}

.prologue-intro__note-caption {
  font-size: clamp(0.84rem, 1.1vw, 0.94rem) !important;
  line-height: 1.9;
  color: rgba(255, 232, 243, 0.72) !important;
  text-shadow:
    0 0 1px rgba(255, 205, 232, 0.45),
    0 0 8px rgba(255, 112, 189, 0.1) !important;
}

.prologue-scenes {
  padding: 0 0 90px;
}

.prologue-echo {
  padding: 72px 0 120px;
}

.prologue-echo__inner {
  width: min(1160px, calc(100% - 40px));
  margin: 0 auto;
}

.prologue-echo__title {
  margin: 0 0 24px;
  text-align: center;
  font-family: "Times New Roman", "Yu Mincho", serif;
  font-size: clamp(1.8rem, 2.8vw, 2.9rem);
  letter-spacing: 0.22em;
  color: rgba(255, 236, 246, 0.96);
  text-shadow:
    0 0 1px rgba(255, 225, 239, 0.95),
    0 0 10px rgba(255, 144, 204, 0.4),
    0 0 22px rgba(255, 112, 189, 0.22);
}

.prologue-echo__body {
  padding: 34px 36px;
  border-radius: 22px;
  border: 1px solid rgba(255, 255, 255, 0.1);
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.05), rgba(255, 255, 255, 0.02));
  box-shadow: 0 18px 46px rgba(0, 0, 0, 0.22);
}

.prologue-echo__body p {
  margin: 0 0 22px;
  font-size: clamp(1rem, 1.45vw, 1.08rem);
  line-height: 2.08;
  color: rgba(255, 244, 250, 0.88);
}

.prologue-echo__body p:last-child {
  margin-bottom: 0;
}

.prologue-echo__banner {
  display: block;
  margin-top: 28px;
  border-radius: 18px;
  overflow: hidden;
  border: 1px solid rgba(255, 255, 255, 0.1);
  box-shadow: 0 18px 42px rgba(0, 0, 0, 0.24);
  filter:
    drop-shadow(0 0 4px rgba(255, 170, 220, 0.34))
    drop-shadow(0 0 10px rgba(255, 120, 196, 0.18));
  transition: transform 0.32s ease, filter 0.32s ease, border-color 0.32s ease, box-shadow 0.32s ease;
}

.prologue-echo__banner:hover,
.prologue-echo__banner:focus-visible {
  transform: scale(1.02);
  border-color: rgba(255, 175, 225, 0.92);
  box-shadow: 0 18px 42px rgba(0, 0, 0, 0.24);
  filter:
    drop-shadow(0 0 6px rgba(255, 178, 226, 0.78))
    drop-shadow(0 0 16px rgba(255, 120, 196, 0.42));
}

.prologue-echo__banner img {
  width: 100%;
  height: auto;
}

.prologue-echo__copyright {
  margin: 34px 0 0;
  text-align: center;
  font-size: 0.82rem;
  letter-spacing: 0.08em;
  color: rgba(255, 244, 250, 0.62);
}

.prologue-scenes__inner {
  display: grid;
  gap: 72px;
}

.scene-card {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
  align-items: stretch;
}

.scene-card__media {
  position: relative;
  width: min(76%, 760px);
  min-height: 100%;
  border-radius: 24px;
  overflow: hidden;
  box-shadow: 0 28px 80px rgba(0, 0, 0, 0.36);
  z-index: 1;
}

.scene-card--reverse .scene-card__media {
  margin-left: auto;
}

.scene-card__content {
  position: absolute;
  right: 0;
  bottom: -34px;
  width: min(45%, 420px);
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 36px 36px 38px;
  border-radius: 22px;
  border: 1px solid rgba(255, 255, 255, 0.1);
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.06), rgba(255, 255, 255, 0.02)),
    rgba(10, 14, 22, 0.84);
  box-shadow: 0 18px 48px rgba(0, 0, 0, 0.28);
  z-index: 2;
}

.scene-card--reverse .scene-card__content {
  right: auto;
  left: 0;
}

.scene-card__head {
  padding: 0;
  margin-bottom: 16px;
}

.scene-card__title {
  margin: 0;
  font-size: clamp(1.8rem, 2.5vw, 2.7rem);
  font-family: "Times New Roman", "Yu Mincho", serif;
  letter-spacing: 0.08em;
}

.scene-card__image-wrap {
  position: relative;
  min-height: 500px;
  overflow: hidden;
  background: rgba(255, 255, 255, 0.03);
  cursor: pointer;
}

.scene-card__image-wrap img {
  width: 100%;
  height: calc(100% + 56px);
  object-fit: cover;
  transform: translate3d(0, 0, 0);
  will-change: transform, opacity;
  transition: opacity 0.42s ease;
}

.scene-card__image-wrap.is-fading img {
  opacity: 0.3;
}

.scene-card__hint {
  position: absolute;
  bottom: 16px;
  z-index: 3;
  display: inline-flex;
  align-items: center;
  padding: 7px 12px;
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  color: rgba(255, 255, 255, 0.9);
  background: rgba(8, 12, 20, 0.62);
  border: 1px solid rgba(255, 255, 255, 0.16);
  border-radius: 999px;
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  pointer-events: none;
}

.scene-card__image-wrap--hint-left .scene-card__hint {
  left: 16px;
}

.scene-card__image-wrap--hint-right .scene-card__hint {
  right: 16px;
}

.scene-card__text p {
  margin: 0;
  color: var(--muted);
  line-height: 2.1;
  font-size: 0.98rem;
}

@media (max-width: 980px) {
  .prologue-header__inner {
    flex-direction: column;
    align-items: flex-start;
  }

  .prologue-nav {
    justify-content: flex-start;
  }

  .prologue-scenes__inner {
    gap: 52px;
  }

  .scene-card__media,
  .scene-card--reverse .scene-card__media {
    width: 100%;
    margin-left: 0;
  }

  .scene-card__content,
  .scene-card--reverse .scene-card__content {
    position: relative;
    right: auto;
    left: auto;
    bottom: auto;
    width: min(100%, 100%);
    margin: -40px 24px 0;
    padding: 28px 24px 30px;
  }

  .scene-card__image-wrap {
    min-height: 0;
    height: auto;
  }

  .scene-card__image-wrap img {
    height: auto;
  }
}

@media (prefers-reduced-motion: reduce) {
  .prologue-particles {
    display: none;
  }
}

@media (max-width: 640px) {
  .prologue-header__inner,
  .prologue-hero__inner,
  .prologue-intro__inner,
  .prologue-scenes__inner {
    width: min(100% - 24px, 1160px);
  }

  .prologue-header__inner {
    padding: 14px 0;
  }

  .prologue-nav {
    width: 100%;
    justify-content: flex-start;
    gap: 14px;
    overflow-x: auto;
    padding-bottom: 4px;
  }

  .prologue-nav a {
    flex: 0 0 auto;
  }

  .prologue-hero {
    padding-top: 28px;
  }

  .prologue-intro {
    padding-bottom: 48px;
  }

  .prologue-intro__heading-wrap {
    width: min(100% - 24px, 1160px);
    margin-bottom: 18px;
  }

  .prologue-echo__inner {
    width: min(100% - 24px, 1160px);
  }

  .prologue-scenes__inner {
    gap: 40px;
  }

  .scene-card__content,
  .scene-card--reverse .scene-card__content {
    margin: -24px 14px 0;
    padding: 22px 18px 24px;
  }

  .scene-card__title {
    font-size: clamp(1.4rem, 6vw, 1.9rem);
  }

  .prologue-echo {
    padding: 44px 0 84px;
  }

  .prologue-echo__body {
    padding: 24px 18px 26px;
  }
}