:root {
  --bg-color: #f0f0f0;
  --text-color: #333;
  --ui-bg: rgba(255, 255, 255, 0.9);
  --accent-color: #ff0055;
}

[data-theme="dark"] {
  --bg-color: #1a1a1a;
  --text-color: #f0f0f0;
  --ui-bg: rgba(0, 0, 0, 0.8);
  --accent-color: #00ffaa;
}

body, html {
  margin: 0;
  padding: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  background-color: var(--bg-color);
  color: var(--text-color);
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  user-select: none;
  -webkit-user-select: none;
}

#game-container {
  width: 100%;
  height: 100%;
  position: absolute;
  top: 0;
  left: 0;
  z-index: 1;
}

#ui-layer {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 10;
  pointer-events: none; /* Let clicks pass through to game when not interacting with UI */
}

.screen {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background: var(--ui-bg);
  padding: 2rem;
  border-radius: 1rem;
  text-align: center;
  box-shadow: 0 4px 6px rgba(0,0,0,0.1);
  pointer-events: auto;
  display: none;
  min-width: 300px;
}

.screen.active {
  display: block;
}

h1 {
  margin-top: 0;
  font-size: 2.5rem;
  color: var(--accent-color);
  text-transform: uppercase;
  letter-spacing: 2px;
}

button {
  background: var(--accent-color);
  color: #fff;
  border: none;
  padding: 1rem 2rem;
  font-size: 1.2rem;
  border-radius: 0.5rem;
  cursor: pointer;
  margin-top: 1rem;
  transition: transform 0.1s, opacity 0.2s;
}

button:hover {
  opacity: 0.9;
  transform: scale(1.05);
}

button:active {
  transform: scale(0.95);
}

#hud {
  position: absolute;
  top: 1rem;
  left: 1rem;
  right: 1rem;
  display: flex;
  justify-content: space-between;
  pointer-events: none;
  font-size: 1.5rem;
  font-weight: bold;
}

#theme-toggle {
  pointer-events: auto;
  background: none;
  border: 2px solid var(--text-color);
  color: var(--text-color);
  padding: 0.5rem;
  font-size: 1rem;
  margin: 0;
}

.score-value {
  color: var(--accent-color);
}