html, body {
  margin: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: #151715;
  color: #fff;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Yu Gothic", sans-serif;
  touch-action: none;
  user-select: none;
}

.app {
  width: 100%;
  height: 100%;
  display: grid;
  place-items: center;
  position: relative;
}

#game {
  width: min(100vw, calc(100vh * 390 / 700));
  height: min(100vh, calc(100vw * 700 / 390));
  max-width: 430px;
  max-height: 100vh;
  background: #1d241d;
  display: block;
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.35);
  border-radius: 18px;
}