:root {
  --bg: #01050c;
  --bg-2: #071324;
  --surface: #0c1d35;
  --surface-2: #112645;
  --line: rgb(90 190 255 / 0.16);
  --text: #e6f3ff;
  --text-2: #9db4d3;
  --text-3: #5f7898;
  --var: #2ee9ff;
  --var-ink: #00121c;
  --var-soft: rgb(46 233 255 / 0.12);
  --font-ui: "Instrument Sans", -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Hiragino Kaku Gothic ProN", system-ui, sans-serif;
  --font-serif: "Newsreader", "Hiragino Mincho ProN", "YuMincho", Georgia, serif;
  --font-mono: "JetBrains Mono", ui-monospace, "SF Mono", Menlo, monospace;
  --radius: 14px;
  --max: 1080px;
  color-scheme: dark;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-ui);
  font-size: 17px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

:lang(ja) body, body:lang(ja) { line-height: 1.85; font-size: 16px; }

/* 中国語と韓国語は日本語のヒラギノではなく、それぞれの言語用のシステムフォントで表示する */
:lang(zh) { --font-ui: "Instrument Sans", -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif; --font-serif: "Newsreader", "Songti SC", Georgia, serif; }
:lang(ko) { --font-ui: "Instrument Sans", -apple-system, BlinkMacSystemFont, "Apple SD Gothic Neo", "Malgun Gothic", system-ui, sans-serif; --font-serif: "Newsreader", "AppleMyungjo", Georgia, serif; }
:lang(zh) body, body:lang(zh), :lang(ko) body, body:lang(ko) { line-height: 1.85; font-size: 16px; }

a { color: var(--var); text-decoration: none; }
a:hover { text-decoration: underline; }

code, kbd {
  font-family: var(--font-mono);
  font-size: 0.88em;
}

code {
  padding: 0.1em 0.4em;
  border-radius: 5px;
  background: var(--var-soft);
  color: var(--var);
}

kbd {
  display: inline-block;
  min-width: 1.8em;
  padding: 0.05em 0.45em;
  border-radius: 6px;
  background: var(--surface-2);
  box-shadow: inset 0 -2px 0 rgb(0 0 0 / 0.35);
  color: var(--text);
  text-align: center;
}

.skip {
  position: absolute;
  left: -9999px;
}
.skip:focus { left: 16px; top: 12px; z-index: 10; }

.wrap {
  width: 100%;
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 24px;
}

/* header */
.top {
  position: sticky;
  top: 0;
  z-index: 5;
  background: rgb(1 5 12 / 0.82);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line);
}
.top .wrap {
  display: flex;
  align-items: center;
  gap: 24px;
  height: 60px;
}
.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  font-weight: 600;
  letter-spacing: -0.01em;
}
.logo:hover { text-decoration: none; }
.logo img { width: 28px; height: 28px; }
.nav {
  display: flex;
  align-items: center;
  gap: 20px;
  margin-left: auto;
  font-size: 14px;
}
.nav a { color: var(--text-2); }
.nav a:hover { color: var(--text); text-decoration: none; }
/* 下の汎用の details / summary の装飾を打ち消す */
.lang { position: relative; max-width: none; margin: 0; padding: 0; border: 0; }
.lang summary {
  padding: 4px 10px;
  font-size: inherit;
  font-weight: 400;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--text-2);
  cursor: pointer;
  list-style: none;
}
.lang summary::-webkit-details-marker { display: none; }
.lang summary::after { content: " ▾"; font-size: 0.8em; }
.lang summary:hover { color: var(--text); }
.lang ul {
  position: absolute;
  right: 0;
  top: calc(100% + 8px);
  min-width: 140px;
  margin: 0;
  padding: 6px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--surface);
  list-style: none;
}
.lang ul a {
  display: block;
  padding: 4px 10px;
  border-radius: 6px;
  white-space: nowrap;
}
.lang ul a:hover { background: var(--surface-2); }
.lang ul a[aria-current] { color: var(--text); }

/* hero */
.hero {
  position: relative;
  padding: 96px 0 48px;
  text-align: center;
  overflow: hidden;
}
.hero::before {
  content: "";
  position: absolute;
  inset: -20% -10% auto;
  height: 520px;
  background: radial-gradient(closest-side, rgb(46 233 255 / 0.16), transparent);
  pointer-events: none;
}
.hero > * { position: relative; }
.hero-icon { width: 96px; height: 96px; margin-bottom: 20px; }
.eyebrow {
  margin: 0 0 16px;
  color: var(--var);
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}
h1 {
  margin: 0 auto;
  overflow-wrap: anywhere;
  max-width: 14em;
  font-family: var(--font-serif);
  font-size: clamp(40px, 7vw, 72px);
  font-weight: 500;
  line-height: 1.08;
  letter-spacing: -0.02em;
}
:lang(ja) h1, :lang(zh) h1, :lang(ko) h1 { font-size: clamp(26px, 5.6vw, 56px); line-height: 1.3; letter-spacing: 0; }
.lede {
  max-width: 36em;
  margin: 24px auto 0;
  color: var(--text-2);
  font-size: 19px;
}
:lang(ja) .lede, :lang(zh) .lede, :lang(ko) .lede { font-size: 17px; }

.cta {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
  margin-top: 36px;
}
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 20px;
  border-radius: 10px;
  font-weight: 600;
  font-size: 15px;
  transition: transform 0.15s, background 0.15s;
}
.btn:hover { text-decoration: none; transform: translateY(-1px); }
.btn-primary { background: var(--var); color: var(--var-ink); }
.btn-primary:hover { background: #8ff6ff; }
.btn-ghost { background: var(--surface); color: var(--text); }
.btn-ghost:hover { background: var(--surface-2); }
.btn small { font-weight: 400; opacity: 0.75; }
.meta {
  margin-top: 14px;
  color: var(--text-3);
  font-size: 13px;
}

.shot {
  margin: 56px auto 0;
  max-width: 1040px;
  border-radius: var(--radius);
  box-shadow: 0 40px 100px -30px rgb(46 233 255 / 0.25), 0 24px 64px -16px rgb(0 4 12 / 0.9);
  border: 1px solid var(--line);
  overflow: hidden;
}
.shot img { display: block; width: 100%; height: auto; }
/* 宣伝用画像は明るい地なので、暗いページの中でポスターのように浮かせる。ヒーローのボタンの下で機能をひと目で見せ、画面写真と幅をそろえる */
.poster {
  max-width: 1040px;
  margin: 56px auto 0;
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: 0 0 0 1px rgb(255 255 255 / 0.08), 0 40px 100px -30px rgb(46 233 255 / 0.35), 0 24px 64px -16px rgb(0 4 12 / 0.9);
}
.poster img, .poster video { display: block; width: 100%; height: auto; }

/* sections */
section { padding: 88px 0; }
section + section { border-top: 1px solid var(--line); }

.label {
  margin: 0 0 12px;
  color: var(--var);
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
}
h2 {
  margin: 0 0 20px;
  overflow-wrap: anywhere;
  font-family: var(--font-serif);
  font-size: clamp(30px, 4.4vw, 44px);
  font-weight: 500;
  line-height: 1.15;
  letter-spacing: -0.015em;
}
:lang(ja) h2, :lang(zh) h2, :lang(ko) h2 { font-size: clamp(26px, 3.8vw, 36px); line-height: 1.4; letter-spacing: 0; }
.intro { max-width: 40em; margin: 0 0 40px; color: var(--text-2); }

h3 { margin: 0 0 8px; font-size: 18px; font-weight: 600; }
p { margin: 0 0 12px; }

/* prompt syntax showcase */
.syntax {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}
.card {
  padding: 24px;
  border-radius: var(--radius);
  background: var(--bg-2);
  border: 1px solid var(--line);
}
.card p { color: var(--text-2); font-size: 15px; }
.card pre {
  margin: 0 0 16px;
  padding: 14px 16px;
  border-radius: 10px;
  background: var(--surface);
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.6;
  white-space: pre-wrap;
  word-break: break-word;
  color: var(--text);
}
.v { color: var(--var); background: var(--var-soft); border-radius: 4px; padding: 0 2px; }
.m { color: var(--text-3); }

/* split feature */
.split {
  display: grid;
  grid-template-columns: 1fr 1.1fr;
  gap: 56px;
  align-items: center;
}
.split .shot { margin: 0; }
.points { list-style: none; margin: 24px 0 0; padding: 0; }
.points li { padding: 12px 0; border-top: 1px solid var(--line); color: var(--text-2); font-size: 15px; }
.points strong { color: var(--text); font-weight: 600; }

/* feature grid */
.grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}
.grid > div { padding: 28px; background: var(--bg); }
.grid p { color: var(--text-2); font-size: 15px; margin: 0; }

/* keys */
.keys {
  width: 100%;
  border-collapse: collapse;
  font-size: 15px;
}
.keys td { padding: 12px 0; border-top: 1px solid var(--line); vertical-align: top; }
.keys td:first-child { width: 42%; padding-right: 16px; white-space: nowrap; }
.keys td:last-child { color: var(--text-2); }
.keys-cols { display: grid; grid-template-columns: 1fr 1fr; gap: 0 48px; }

/* download */
.download { text-align: center; }
.download .intro { margin-left: auto; margin-right: auto; }
.notes {
  max-width: 40em;
  margin: 40px auto 0;
  padding: 0;
  list-style: none;
  text-align: left;
  color: var(--text-2);
  font-size: 15px;
}
.notes li { padding: 10px 0 10px 24px; position: relative; }
.notes li::before { content: "❯"; position: absolute; left: 0; color: var(--var); font-size: 13px; top: 12px; }

details {
  max-width: 40em;
  margin: 24px auto 0;
  text-align: left;
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 0 18px;
}
summary { cursor: pointer; padding: 14px 0; font-weight: 600; font-size: 15px; }
details pre {
  margin: 0 0 18px;
  padding: 14px 16px;
  border-radius: 8px;
  background: var(--bg-2);
  font-family: var(--font-mono);
  font-size: 13px;
  overflow-x: auto;
}

/* faq */
.faq { max-width: 44em; }
.faq dt { margin-top: 28px; font-weight: 600; }
.faq dd { margin: 6px 0 0; color: var(--text-2); font-size: 15px; }

/* privacy policy */
.doc { padding: 72px 0 88px; }
.doc .wrap { max-width: 760px; }
.doc h1 { margin: 0; max-width: none; font-size: clamp(34px, 5vw, 48px); }
:lang(ja) .doc h1, :lang(zh) .doc h1, :lang(ko) .doc h1 { font-size: clamp(26px, 4vw, 36px); }
.doc .meta { margin: 8px 0 40px; }
.doc h2 { margin: 48px 0 12px; font-size: 24px; }
:lang(ja) .doc h2, :lang(zh) .doc h2, :lang(ko) .doc h2 { font-size: 22px; }
.doc p, .doc li { color: var(--text-2); }
.doc strong { color: var(--text); font-weight: 600; }
.doc ul { margin: 0 0 12px; padding-left: 1.2em; }
.doc li { margin-bottom: 8px; }
.doc code { overflow-wrap: anywhere; }

/* footer */
.foot {
  padding: 40px 0 56px;
  border-top: 1px solid var(--line);
  color: var(--text-3);
  font-size: 14px;
}
.foot .wrap { display: flex; flex-wrap: wrap; gap: 16px 24px; align-items: center; }
.foot .logo { font-size: 15px; }
.foot nav { display: flex; gap: 20px; margin-left: auto; }
.foot a:not(.logo) { color: var(--text-2); }
.foot .langs { flex-basis: 100%; display: flex; flex-wrap: wrap; gap: 6px 16px; margin-left: 0; font-size: 13px; }

@media (max-width: 860px) {
  .syntax, .grid { grid-template-columns: minmax(0, 1fr); }
  .split { grid-template-columns: minmax(0, 1fr); gap: 32px; }
  .keys-cols { grid-template-columns: minmax(0, 1fr); }
  .nav > a:not(.gh) { display: none; }
}

@media (max-width: 520px) {
  .wrap { padding: 0 16px; }
  .hero { padding-top: 64px; }
  section { padding: 64px 0; }
  .btn { width: 100%; justify-content: center; }
  .keys td:first-child { white-space: normal; }
  :lang(ja) h2 br, :lang(ja) h1 br { display: none; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .btn { transition: none; }
}

.nw { display: inline-block; }
code, kbd, pre { font-variant-ligatures: none; }