body {
  margin: 0;
  overflow: hidden;
  background-color: #000;
}
#gameCanvas {
  display: block;
  width: 100vw;
  height: 100vh;
  max-width: 100vw;
  max-height: 100vh;
  touch-action: none;
  background: #000;
}

/* On-screen controls for mobile */
#mobileControls {
  position: fixed;
  bottom: 0;
  left: 0;
  width: 100vw;
  display: flex;
  justify-content: space-between;
  padding: 10px;
  box-sizing: border-box;
  z-index: 10;
  pointer-events: none;
}
.mobile-btn {
  width: 80px;
  height: 80px;
  background: rgba(255,255,255,0.15);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2em;
  color: #fff;
  margin: 0 10px;
  pointer-events: auto;
  border: 2px solid #fff;
  user-select: none;
}
@media (max-width: 600px) {
  #gameCanvas {
    height: 100dvh;
  }
  .mobile-btn {
    width: 60px;
    height: 60px;
    font-size: 1.5em;
  }
}