/* 月夜 -TSUKIYO- */
:root {
  --ink: #eef0f6;
  --ink-dim: #b9bdcf;
  --gold: #c9b47a;
  --bg: #060811;
  --serif: 'Shippori Mincho', 'Hiragino Mincho ProN', serif;
  --en: 'Cormorant Garamond', var(--serif);
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--serif);
  overflow-x: hidden;
}

.stage {
  position: fixed;
  inset: 0;
  width: 100vw;
  height: 100vh;
  z-index: 0;
}

main {
  position: relative;
  z-index: 1;
}

/* ---- セクション共通 ---- */
.sec {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 8vh 6vw;
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 1.4s ease, transform 1.4s ease;
}

.sec.on {
  opacity: 1;
  transform: none;
}

/* ---- HERO ---- */
.hero {
  min-height: 130vh;
  position: relative;
}

.hero-inner {
  display: flex;
  align-items: flex-start;
  gap: 4vw;
}

.hero-title {
  writing-mode: vertical-rl;
  font-size: clamp(4.4rem, 11vw, 9rem);
  font-weight: 500;
  letter-spacing: 0.34em;
  text-shadow: 0 0 42px rgba(233, 226, 198, 0.35);
}

.hero-sub {
  writing-mode: vertical-rl;
  font-size: clamp(0.95rem, 2vw, 1.25rem);
  letter-spacing: 0.5em;
  color: var(--ink-dim);
  padding-top: 1.2em;
}

.hero-en {
  position: absolute;
  bottom: 18vh;
  font-family: var(--en);
  font-size: clamp(0.7rem, 1.4vw, 0.95rem);
  letter-spacing: 0.55em;
  color: var(--gold);
  text-transform: uppercase;
}

.scroll-cue {
  position: absolute;
  bottom: 6vh;
  font-size: 0.8rem;
  letter-spacing: 0.5em;
  color: var(--ink-dim);
  animation: cue 3.2s ease-in-out infinite;
}

@keyframes cue {
  0%, 100% { opacity: 0.35; transform: translateY(0); }
  50% { opacity: 0.9; transform: translateY(6px); }
}

/* ---- PRESENCE ---- */
.presence-line {
  font-size: clamp(1.05rem, 2.4vw, 1.6rem);
  letter-spacing: 0.22em;
  line-height: 2.6;
  text-align: center;
  max-width: 34em;
}

.presence-sign {
  margin-top: 3.2em;
  font-size: 0.85rem;
  letter-spacing: 0.4em;
  color: var(--gold);
}

/* ---- FEATURE ---- */
.feature {
  align-items: flex-start;
}

.feature.right {
  align-items: flex-end;
}

.feature-card {
  max-width: 30em;
  padding: 3.2em 3em;
  border: 1px solid rgba(201, 180, 122, 0.35);
  background: rgba(6, 8, 17, 0.55);
  backdrop-filter: blur(6px);
}

.feature-en {
  font-family: var(--en);
  font-size: 0.72rem;
  letter-spacing: 0.5em;
  color: var(--gold);
  margin-bottom: 1.6em;
}

.feature-title {
  font-size: clamp(1.5rem, 3vw, 2.1rem);
  font-weight: 500;
  letter-spacing: 0.18em;
  margin-bottom: 1.2em;
}

.feature-copy {
  font-size: 0.95rem;
  line-height: 2.3;
  letter-spacing: 0.08em;
  color: var(--ink-dim);
}

/* ---- CTA ---- */
.cta {
  background: radial-gradient(ellipse 60% 50% at 50% 45%, rgba(6, 8, 17, 0.7), transparent 72%);
}

.cta-title {
  font-size: clamp(1.6rem, 3.6vw, 2.4rem);
  font-weight: 500;
  letter-spacing: 0.2em;
  margin-bottom: 1.4em;
  text-align: center;
}

.cta-copy {
  font-size: 0.95rem;
  letter-spacing: 0.12em;
  line-height: 2.2;
  color: var(--ink-dim);
  text-align: center;
  margin-bottom: 3em;
}

.cta-actions {
  display: flex;
  gap: 1.4em;
  flex-wrap: wrap;
  justify-content: center;
}

.cta-btn {
  display: inline-block;
  padding: 1em 2.6em;
  border: 1px solid rgba(201, 180, 122, 0.55);
  color: var(--ink);
  text-decoration: none;
  font-size: 0.9rem;
  letter-spacing: 0.28em;
  transition: background 0.5s ease, color 0.5s ease;
}

.cta-btn:hover {
  background: rgba(201, 180, 122, 0.16);
  color: #fff;
}

/* ---- FIN ---- */
.fin-line {
  font-size: clamp(1.2rem, 2.6vw, 1.7rem);
  letter-spacing: 0.34em;
}

.fin-credit {
  margin-top: 4em;
  font-family: var(--en);
  font-size: 0.7rem;
  letter-spacing: 0.3em;
  color: var(--ink-dim);
}

/* ---- サウンドゲート ---- */
.sound-gate {
  position: fixed;
  inset: 0;
  z-index: 30;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(4, 5, 10, 0.62);
  backdrop-filter: blur(10px);
  transition: opacity 0.6s ease;
}

.sound-gate.closing {
  opacity: 0;
  pointer-events: none;
}

.sound-gate-panel {
  width: min(88vw, 24em);
  padding: 3em 2.6em;
  border: 1px solid rgba(201, 180, 122, 0.5);
  background: rgba(8, 10, 20, 0.9);
  text-align: center;
}

.sound-gate-en {
  font-family: var(--en);
  font-size: 0.75rem;
  letter-spacing: 0.55em;
  color: var(--gold);
  margin-bottom: 1.6em;
}

.sound-gate-text {
  font-size: 0.95rem;
  letter-spacing: 0.18em;
  margin-bottom: 2.2em;
}

.sound-gate-actions {
  display: flex;
  flex-direction: column;
  gap: 1em;
}

.sound-gate-btn {
  padding: 1em;
  font-family: var(--serif);
  font-size: 0.9rem;
  letter-spacing: 0.3em;
  color: var(--ink);
  background: transparent;
  border: 1px solid rgba(238, 240, 246, 0.4);
  cursor: pointer;
  transition: background 0.4s ease;
}

.sound-gate-btn:hover {
  background: rgba(201, 180, 122, 0.16);
}

/* ---- 音ボタン・GPUバッジ ---- */
.audio-btn {
  position: fixed;
  right: 1.6em;
  bottom: 1.6em;
  z-index: 20;
  padding: 0.9em 1.6em;
  font-family: var(--serif);
  font-size: 0.8rem;
  letter-spacing: 0.24em;
  color: var(--ink);
  background: rgba(8, 10, 20, 0.7);
  border: 1px solid rgba(201, 180, 122, 0.45);
  cursor: pointer;
}

.audio-btn.on::before {
  content: '● ';
  color: var(--gold);
  font-size: 0.6em;
  vertical-align: 0.2em;
}

.gpu-badge {
  position: fixed;
  left: 1.4em;
  bottom: 1.4em;
  z-index: 20;
  font-family: var(--en);
  font-size: 0.6rem;
  letter-spacing: 0.35em;
  color: rgba(185, 189, 207, 0.55);
}

/* ---- モバイル ---- */
@media (max-width: 640px) {
  .feature,
  .feature.right {
    align-items: center;
  }

  .feature-card {
    padding: 2.4em 1.8em;
  }

  .hero-en {
    letter-spacing: 0.3em;
    text-align: center;
  }
}

@media (prefers-reduced-motion: reduce) {
  .sec {
    transition: none;
  }

  .scroll-cue {
    animation: none;
  }
}