:root {
  color-scheme: dark;
  --bg: #050816;
  --panel: rgba(9, 15, 38, 0.74);
  --line: rgba(116, 232, 255, 0.25);
  --cyan: #74e8ff;
  --violet: #b683ff;
  --text: #f6fbff;
  --muted: #9eacc5;
}

* { box-sizing: border-box; }
html, body { width: 100%; height: 100%; margin: 0; overflow: hidden; background: var(--bg); }
body { font-family: Inter, "Noto Sans JP", system-ui, -apple-system, sans-serif; color: var(--text); }
button { font: inherit; }

#app { position: fixed; inset: 0; width: 100%; height: 100%; display: block; }

#landing {
  position: fixed;
  inset: 0;
  display: grid;
  grid-template-columns: minmax(320px, 720px) minmax(250px, 360px);
  gap: clamp(24px, 6vw, 96px);
  align-items: center;
  justify-content: center;
  padding: clamp(24px, 6vw, 88px);
  background: radial-gradient(circle at 65% 28%, rgba(81, 83, 255, .12), transparent 32%),
              linear-gradient(90deg, rgba(5,8,22,.94), rgba(5,8,22,.55));
  pointer-events: none;
}

.hero, .feature-card { pointer-events: auto; }
.eyebrow { margin: 0 0 12px; letter-spacing: .28em; color: var(--cyan); font-size: 12px; font-weight: 800; }
h1 { margin: 0; font-size: clamp(52px, 9vw, 124px); line-height: .9; letter-spacing: -.07em; }
h1 span { color: var(--violet); }
.lead { max-width: 560px; margin: 24px 0 34px; color: #dbe7f7; font-size: clamp(18px, 2vw, 27px); line-height: 1.6; }

.mode-row, .action-row { display: flex; gap: 10px; flex-wrap: wrap; }
.mode-row { margin-bottom: 14px; }
button { border: 0; cursor: pointer; }
.mode {
  padding: 10px 15px;
  border: 1px solid rgba(255,255,255,.13);
  border-radius: 999px;
  color: var(--muted);
  background: rgba(255,255,255,.04);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: .09em;
}
.mode.active { color: #07101c; background: var(--cyan); border-color: var(--cyan); }
.primary, .secondary {
  min-height: 52px;
  padding: 0 24px;
  border-radius: 14px;
  font-weight: 850;
  transition: transform .15s ease, filter .15s ease;
}
.primary { color: #07101c; background: linear-gradient(135deg, var(--cyan), #bdf7ff); box-shadow: 0 14px 40px rgba(65, 218, 255, .22); }
.secondary { color: var(--text); background: rgba(255,255,255,.08); border: 1px solid rgba(255,255,255,.13); }
.primary:hover, .secondary:hover { transform: translateY(-2px); filter: brightness(1.08); }
.primary:disabled { opacity: .45; cursor: not-allowed; transform: none; }
.status { color: var(--muted); font-size: 13px; margin: 15px 0 0; }
.safety { max-width: 620px; margin-top: 22px; padding: 14px 16px; border-left: 2px solid var(--violet); background: rgba(182,131,255,.07); color: #b8c3d7; font-size: 13px; line-height: 1.65; }

.feature-card {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  padding: 1px;
  border: 1px solid var(--line);
  border-radius: 24px;
  overflow: hidden;
  background: var(--line);
  box-shadow: 0 30px 90px rgba(0,0,0,.35);
}
.feature-card > div { padding: 23px 12px; text-align: center; background: var(--panel); }
.feature-card b { display: block; color: var(--cyan); font-size: 26px; }
.feature-card span { display: block; margin-top: 4px; color: var(--muted); font-size: 11px; }
.feature-card p { grid-column: 1 / -1; margin: 0; padding: 20px; background: var(--panel); color: #b9c4d7; font-size: 13px; line-height: 1.7; }

#desktop-hud {
  position: fixed;
  top: 16px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 3;
  align-items: center;
  gap: 14px;
  padding: 9px 12px 9px 16px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(5,8,22,.78);
  backdrop-filter: blur(16px);
  font-size: 13px;
}
#desktop-hud:not([hidden]) { display: flex; }
#desktop-hud button { padding: 7px 12px; border-radius: 999px; color: #07101c; background: var(--cyan); font-weight: 800; }

@media (max-width: 850px) {
  #landing { grid-template-columns: 1fr; align-content: center; overflow-y: auto; }
  .feature-card { display: none; }
  h1 { font-size: clamp(58px, 19vw, 98px); }
}