html,
body {
  margin: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  background:
    radial-gradient(circle at 18% 12%, rgba(255, 111, 145, 0.32), transparent 28%),
    radial-gradient(circle at 82% 10%, rgba(24, 210, 209, 0.28), transparent 30%),
    linear-gradient(165deg, #171b32 0%, #212b42 45%, #162733 100%);
  color: #f8fbff;
  font-family: "Segoe UI", "Hiragino Kaku Gothic ProN", Meiryo, sans-serif;
  touch-action: none;
  user-select: none;
}

#game-shell {
  display: grid;
  place-items: center;
  height: 100%;
  height: 100dvh;
  padding: env(safe-area-inset-top) env(safe-area-inset-right) env(safe-area-inset-bottom) env(safe-area-inset-left);
  box-sizing: border-box;
}

#game {
  width: min(100vw, 720px);
  height: min(100vh, 1280px);
  height: min(100dvh, 1280px);
  display: grid;
  place-items: center;
}

canvas {
  display: block;
  max-width: 100%;
  max-height: 100%;
  border-radius: 8px;
  box-shadow: 0 22px 70px rgba(0, 0, 0, 0.45);
}