:root {
  color-scheme: dark;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: #061014;
  color: #f7fcff;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(circle at top, rgba(112, 240, 208, 0.20), transparent 34rem),
    radial-gradient(circle at bottom right, rgba(92, 135, 255, 0.18), transparent 30rem),
    #061014;
}

.demo-shell {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 24px;
}

.screen {
  display: none;
  width: min(760px, 100%);
  min-height: min(760px, calc(100vh - 72px));
  place-items: center;
  align-content: center;
  gap: 22px;
  text-align: center;
}

.screen.active { display: grid; }

.eyebrow {
  margin: 0;
  color: #70f0d0;
  font-weight: 900;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  font-size: 0.82rem;
}

h1 {
  max-width: 820px;
  margin: 0;
  font-size: clamp(3.1rem, 12vw, 7.5rem);
  line-height: 0.88;
  letter-spacing: -0.08em;
}

.subhead {
  max-width: 680px;
  margin: 0;
  color: #cde5ec;
  font-size: clamp(1.25rem, 3.5vw, 1.85rem);
  line-height: 1.35;
}

button {
  appearance: none;
  border: 0;
  border-radius: 999px;
  padding: 18px 28px;
  min-width: 220px;
  font-size: 1.05rem;
  font-weight: 900;
  color: #031113;
  background: linear-gradient(135deg, #70f0d0, #91b8ff);
  box-shadow: 0 20px 70px rgba(112, 240, 208, 0.22);
  cursor: pointer;
}

button:disabled {
  opacity: 0.55;
  cursor: wait;
}

video {
  width: min(560px, 100%);
  aspect-ratio: 4 / 3;
  border-radius: 32px;
  background: #020609;
  object-fit: cover;
  border: 1px solid rgba(255,255,255,0.12);
  box-shadow: 0 30px 100px rgba(0,0,0,0.36);
}

.biometric-mark {
  width: 150px;
  height: 150px;
  display: grid;
  place-items: center;
  border-radius: 44px;
  border: 4px solid #70f0d0;
  color: #70f0d0;
  font-size: 7rem;
  animation: pulse 0.8s ease-in-out infinite alternate;
}

.timer {
  margin: -8px 0 0;
  color: #70f0d0;
  font-size: clamp(2.4rem, 9vw, 5rem);
  font-weight: 950;
  letter-spacing: -0.06em;
}

.details-link {
  position: fixed;
  left: 50%;
  bottom: 18px;
  transform: translateX(-50%);
  min-width: 0;
  padding: 10px 14px;
  border-radius: 999px;
  color: #cde5ec;
  background: rgba(255,255,255,0.08);
  box-shadow: none;
  font-size: 0.9rem;
}

.details {
  position: fixed;
  inset: auto 16px 64px 16px;
  max-width: 680px;
  margin: 0 auto;
  padding: 22px;
  border-radius: 24px;
  background: rgba(6, 16, 20, 0.96);
  border: 1px solid rgba(255,255,255,0.14);
  box-shadow: 0 30px 90px rgba(0,0,0,0.5);
  color: #d7edf3;
}

.details h2 { margin-top: 0; }

.details-close {
  float: right;
  min-width: 0;
  padding: 8px 12px;
  font-size: 0.85rem;
  background: rgba(255,255,255,0.12);
  color: #f7fcff;
  box-shadow: none;
}

@keyframes pulse {
  from { transform: scale(0.96); opacity: 0.72; }
  to { transform: scale(1.04); opacity: 1; }
}

@media (max-width: 640px) {
  .demo-shell { padding: 16px; }
  .screen { min-height: calc(100vh - 72px); }
  button { width: min(100%, 360px); }
}