:root {
  --bg:#080d12;
  --panel:rgba(17,26,36,.9);
  --line:rgba(255,255,255,.10);
  --line-strong:rgba(103,232,146,.30);
  --text:#eef4f7;
  --muted:#99a8b5;
  --accent:#67e892;
  --accent-soft:rgba(103,232,146,.10);
}
* {
  box-sizing:border-box;
}
body {
  margin:0;
  min-height:100vh;
  color:var(--text);
  background:radial-gradient(circle at 12% 8%,rgba(103,232,146,.08),transparent 28rem),radial-gradient(circle at 86% 18%,rgba(58,113,170,.09),transparent 30rem),linear-gradient(180deg,#080d12 0%,#0a1017 52%,#080d12 100%);
  font-family:Inter,"Noto Sans JP","Hiragino Kaku Gothic ProN","Yu Gothic",Meiryo,system-ui,-apple-system,sans-serif;
  line-height:1.7;
}
.shell {
  width:min(1120px,calc(100% - 40px));
  margin:0 auto;
}
.site-header {
  padding:20px 0 12px;
}
.header-row {
  display:flex;
  align-items:center;
  justify-content:flex-end;
  gap:20px;
}
.lang-switch {
  display:inline-flex;
  flex:0 0 auto;
  padding:3px;
  border:1px solid var(--line);
  border-radius:999px;
  background:rgba(255,255,255,.025);
}
.lang-button {
  min-height:36px;
  padding:6px 12px;
  border:0;
  border-radius:999px;
  color:var(--muted);
  background:transparent;
  font:inherit;
  font-size:.78rem;
  font-weight:800;
  cursor:pointer;
}
.lang-button:hover,.lang-button:focus-visible { color:var(--text); outline:none; }
.lang-button.is-active { color:#07110b; background:var(--accent); }

main {
  padding:16px 0 56px;
}
.hero {
  position:relative;
  overflow:hidden;
  padding:clamp(26px,5vw,52px);
  border:1px solid var(--line);
  border-radius:26px;
  background:linear-gradient(145deg,rgba(255,255,255,.025),rgba(255,255,255,0)),var(--panel);
  box-shadow:0 24px 70px rgba(0,0,0,.35);
  backdrop-filter:blur(14px);
}
.hero:before {
  content:"";
  position:absolute;
  inset:0 auto auto 0;
  width:100%;
  height:1px;
  background:linear-gradient(90deg,transparent,var(--accent),transparent);
  opacity:.55;
}
.category {
  display:inline-flex;
  align-items:center;
  gap:9px;
  margin-bottom:19px;
  padding:7px 12px;
  border:1px solid var(--line-strong);
  border-radius:999px;
  background:var(--accent-soft);
  color:var(--accent);
  font-size:.74rem;
  font-weight:800;
  letter-spacing:.12em;
}
h1 {
  margin:0;
  font-size:clamp(2.1rem,7vw,4.9rem);
  line-height:1.06;
  letter-spacing:-.055em;
  font-weight:900;
}
.lead {
  margin:17px 0 0;
  color:#d5dee5;
  font-size:clamp(1rem,2.2vw,1.24rem);
  font-weight:600;
}
.video-card {
  margin-top:clamp(28px,5vw,44px);
  padding:clamp(10px,2vw,16px);
  border:1px solid var(--line);
  border-radius:18px;
  background:#05080b;
  box-shadow:inset 0 0 0 1px rgba(255,255,255,.02),0 18px 44px rgba(0,0,0,.34);
}
video {
  display:block;
  width:100%;
  height:auto;
  max-height:72vh;
  border-radius:12px;
  background:#000;
  object-fit:contain;
}
.content-grid {
  display:grid;
  grid-template-columns:minmax(0,1fr) auto;
  gap:24px;
  align-items:end;
  margin-top:26px;
  padding-top:25px;
  border-top:1px solid var(--line);
}
.about-label {
  margin:0 0 7px;
  color:var(--accent);
  font-size:.72rem;
  font-weight:800;
  letter-spacing:.17em;
}
.about-text {
  margin:0;
  color:var(--muted);
  font-size:.96rem;
}
.back-link {
  display:inline-flex;
  align-items:center;
  gap:8px;
  min-height:44px;
  padding:9px 14px;
  border:1px solid var(--line);
  border-radius:12px;
  color:var(--text);
  background:rgba(255,255,255,.025);
  text-decoration:none;
  font-size:.88rem;
  font-weight:750;
  white-space:nowrap;
}
.back-link:hover,.back-link:focus-visible {
  border-color:var(--line-strong);
  background:var(--accent-soft);
  outline:none;
}
footer {
  padding:0 0 34px;
  color:#788692;
  font-size:.78rem;
  text-align:center;
}
footer a {
  color:#a7b4be;
  text-decoration:none;
}
footer a:hover,footer a:focus-visible {
  color:var(--accent);
  outline:none;
}

.prompt-section {
  margin-top:26px;
  padding-top:25px;
  border-top:1px solid var(--line);
}

.prompt-label {
  margin:0 0 7px;
  color:var(--accent);
  font-size:.72rem;
  font-weight:800;
  letter-spacing:.17em;
}

.prompt-intro {
  margin:0 0 14px;
  color:var(--muted);
  font-size:.94rem;
}

.prompt-details {
  overflow:hidden;
  border:1px solid var(--line);
  border-radius:14px;
  background:rgba(255,255,255,.018);
}

.prompt-details[open] {
  border-color:var(--line-strong);
}

.prompt-summary {
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:16px;
  min-height:52px;
  padding:12px 16px;
  color:var(--text);
  cursor:pointer;
  font-size:.92rem;
  font-weight:750;
  list-style:none;
  user-select:none;
}

.prompt-summary::-webkit-details-marker {
  display:none;
}

.prompt-summary::after {
  content:"＋";
  flex:0 0 auto;
  color:var(--accent);
  font-size:1.25rem;
  line-height:1;
}

.prompt-details[open] .prompt-summary::after {
  content:"−";
}

.prompt-summary:hover,.prompt-summary:focus-visible {
  background:var(--accent-soft);
  outline:none;
}

.prompt-body {
  padding:0 16px 16px;
  border-top:1px solid var(--line);
}

.prompt-toolbar {
  display:flex;
  justify-content:flex-end;
  padding:12px 0 10px;
}

.copy-prompt {
  min-height:38px;
  padding:7px 12px;
  border:1px solid var(--line-strong);
  border-radius:10px;
  color:var(--accent);
  background:var(--accent-soft);
  font:inherit;
  font-size:.82rem;
  font-weight:800;
  cursor:pointer;
}

.copy-prompt:hover,.copy-prompt:focus-visible {
  background:rgba(103,232,146,.16);
  outline:none;
}

.prompt-text {
  margin:0;
  padding:16px;
  overflow-wrap:anywhere;
  white-space:pre-wrap;
  border:1px solid var(--line);
  border-radius:12px;
  color:#dbe5eb;
  background:#05080b;
  font-family:inherit;
  font-size:.86rem;
  line-height:1.75;
}

.prompt-note {
  margin:11px 2px 0;
  color:#788692;
  font-size:.78rem;
}


.about-section {
  margin-top:26px;
  padding-top:25px;
  border-top:1px solid var(--line);
}

.content-grid-nav {
  grid-template-columns:1fr;
  justify-items:end;
}

@media(max-width:720px) {
  .shell {
    width:min(100% - 24px,1120px);
  }
  .site-header {
    padding:16px 0 10px;
  }
  .header-row { gap:12px; }
  .lang-button { min-height:34px; padding:5px 10px; font-size:.74rem; }
  .hero {
    padding:24px 18px 20px;
    border-radius:20px;
  }
  .content-grid {
    grid-template-columns:1fr;
  }
  .back-link {
    width:100%;
    justify-content:center;
  }
}