:root {
  color-scheme: light;
  font-family: "Nunito", "Avenir", "Helvetica", sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: #0b0f1e;
  color: #f8f8ff;
  height: 100vh;
  overflow: hidden;
  touch-action: none;
}

.app {
  position: relative;
  width: 100vw;
  height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
}

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

.hud {
  position: absolute;
  top: 1.5rem;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 0.75rem;
  padding: 0.5rem 0.75rem;
  border-radius: 999px;
  background: rgba(8, 12, 24, 0.55);
  backdrop-filter: blur(10px);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease;
}

.hud.is-visible {
  opacity: 1;
  pointer-events: auto;
}

.hud-button {
  width: 3rem;
  height: 3rem;
  border-radius: 50%;
  border: none;
  background: rgba(255, 255, 255, 0.15);
  color: inherit;
  font-size: 1.4rem;
  display: grid;
  place-items: center;
  cursor: pointer;
}

.hud-button.is-active {
  background: rgba(255, 255, 255, 0.35);
  box-shadow: 0 0 12px rgba(255, 255, 255, 0.35);
}

.hud-button:active {
  transform: scale(0.96);
}

.start-overlay {
  position: absolute;
  inset: 0;
  border: none;
  background: radial-gradient(circle at center, rgba(24, 32, 64, 0.9), rgba(7, 8, 18, 0.95));
  color: #f9f5ff;
  font-size: 1.6rem;
  letter-spacing: 0.03em;
  display: grid;
  place-items: center;
  cursor: pointer;
  transition: opacity 0.4s ease;
}

.start-overlay.is-hidden {
  opacity: 0;
  pointer-events: none;
}

@media (prefers-reduced-motion: reduce) {
  .hud {
    transition: none;
  }

  .start-overlay {
    transition: none;
  }
}