* { margin: 0; padding: 0; box-sizing: border-box; }
html, body { height: 100%; }
body {
  background: #ffffff;
  color: #000000;
  font-family: -apple-system, "Segoe UI", system-ui, sans-serif;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}
#root { text-align: center; width: 100%; padding: 0 5vw; }
.hidden { display: none !important; }

#heading {
  font-size: 3vw;
  font-weight: 600;
  letter-spacing: 0.04em;
  margin-bottom: 2vh;
  user-select: none;
}

#age {
  font-size: 11vw;
  font-weight: 700;
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
  line-height: 1.1;
  user-select: none;
}

#setup .prompt { font-size: 22px; font-weight: 500; margin-bottom: 20px; color: #111; }
#setup input {
  font-size: 18px;
  padding: 10px 14px;
  border: 1px solid #ccc;
  border-radius: 8px;
}
#setup button {
  display: block;
  margin: 16px auto 0;
  font-size: 18px;
  padding: 10px 28px;
  border: none;
  border-radius: 8px;
  background: #000;
  color: #fff;
  cursor: pointer;
}
.change {
  position: fixed;
  bottom: 18px;
  right: 20px;
  font-size: 12px;
  color: #bbb;
  cursor: pointer;
}
.change:hover { color: #666; }