* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html, body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: #000;
  font-family: system-ui, -apple-system, sans-serif;
  touch-action: none;
  -webkit-touch-callout: none;
  -webkit-user-select: none;
  user-select: none;
  padding: env(safe-area-inset-top) env(safe-area-inset-right) env(safe-area-inset-bottom) env(safe-area-inset-left);
}

#gameContainer {
  width: 100%;
  height: 100%;
  max-width: 420px;
  margin: 0 auto;
  position: relative;
  background: #111;
}

@media (min-width: 421px) {
  #gameContainer {
    height: 100vh;
    border-left: 2px solid #222;
    border-right: 2px solid #222;
  }
}

#gameCanvas {
  display: block;
  width: 100%;
  height: 100%;
}

#muteBtn {
  position: absolute;
  bottom: 16px;
  right: 16px;
  width: 44px;
  height: 44px;
  background: rgba(0,0,0,0.4);
  border: 1px solid rgba(255,255,255,0.2);
  border-radius: 8px;
  color: #fff;
  font-size: 20px;
  cursor: pointer;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: center;
}

#muteBtn:active {
  background: rgba(255,255,255,0.2);
}

@media (orientation: landscape) and (max-height: 500px) {
  #gameContainer {
    max-width: none;
  }
}