piano-midi-monitor/public/style.css

html {
  width: 100%;
  height: 100%;
}

body {
  margin: 0;
  width: 100%;
  height: 100%;
}

#root {
  width: 100%;
  height: 100%;
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: stretch;
}

:root {
  --size-scale-factor: 2;
}