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

html,
body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: #000;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  -webkit-user-select: none;
  user-select: none;
  -webkit-touch-callout: none;
}

#background {
  position: fixed;
  inset: 0;
  background-position: center;
  background-size: cover;
  background-repeat: no-repeat;
  z-index: 0;
}

#unity-canvas {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
  z-index: 10;
  background: transparent;
  touch-action: none;
}

#back-button {
  position: fixed;
  top: max(0.5rem, env(safe-area-inset-top));
  left: max(0.5rem, env(safe-area-inset-left));
  width: 3rem;
  height: 3rem;
  display: none;
  align-items: center;
  justify-content: center;
  border: none;
  background: transparent;
  cursor: pointer;
  z-index: 20;
}

#back-button.visible {
  display: flex;
}

#back-button svg {
  width: 1.5rem;
  height: 1.5rem;
  color: #fff;
  filter: drop-shadow(0 1px 2px rgba(0, 0, 0, 0.4));
}

#loading {
  position: fixed;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1.25rem;
  z-index: 30;
  transition: opacity 0.3s ease;
}

#loading.hidden {
  opacity: 0;
  pointer-events: none;
}

.spinner {
  width: 3rem;
  height: 3rem;
  border: 3px solid rgba(255, 255, 255, 0.25);
  border-top-color: #fff;
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

.progress-track {
  width: 12rem;
  height: 0.375rem;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.25);
  overflow: hidden;
}

.progress-bar {
  height: 100%;
  width: 0%;
  background: #fff;
  border-radius: 999px;
  transition: width 0.2s ease;
}

#error {
  position: fixed;
  inset: 0;
  display: none;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  padding: 2rem;
  text-align: center;
  color: #fff;
  z-index: 40;
}

#error.visible {
  display: flex;
}