:root {
  --bg: #111;
  --fg: #eee;
  --accent: #0f0;
  --danger: #f33;
}

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

html, body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: var(--bg);
  color: var(--fg);
  font-family: 'Segoe UI', system-ui, sans-serif;
  user-select: none;
}

#gl {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
}

#ui {
  position: fixed;
  inset: 0;
  pointer-events: none;
}

#hud {
  position: absolute;
  top: 1rem;
  left: 1rem;
  right: 1rem;
  display: flex;
  gap: 1.5rem;
  font-size: 1.1rem;
  font-weight: 700;
  text-shadow: 0 2px 4px rgba(0,0,0,0.8);
}

#wave { color: var(--accent); }
#score { color: var(--fg); }
#ammo { color: #ffcc00; }
#health { color: var(--danger); margin-left: auto; }

#crosshair {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 2rem;
  color: rgba(255,255,255,0.8);
  text-shadow: 0 0 4px rgba(0,0,0,0.5);
}

#message {
  position: absolute;
  top: 35%;
  left: 50%;
  transform: translateX(-50%);
  font-size: 2.5rem;
  font-weight: 900;
  text-align: center;
  text-shadow: 0 4px 8px rgba(0,0,0,0.9);
  color: var(--accent);
}

#action {
  position: absolute;
  bottom: 2.5rem;
  left: 50%;
  transform: translateX(-50%);
  font-size: 1.1rem;
  font-weight: 700;
  color: #ffcc00;
  text-shadow: 0 2px 4px rgba(0,0,0,0.9);
  min-height: 1.5rem;
}

#message.hidden {
  display: none;
}

#start-screen {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: rgba(0,0,0,0.85);
  pointer-events: auto;
}

#start-screen h1 {
  font-size: 3rem;
  color: var(--accent);
  margin-bottom: 1rem;
}

#start-screen label,
#start-screen select {
  font-size: 1.1rem;
  margin-bottom: 1rem;
}

#start-screen select {
  background: #222;
  color: var(--fg);
  border: 1px solid var(--accent);
  padding: 0.3rem 0.6rem;
  border-radius: 4px;
  margin-bottom: 1rem;
}

#start-screen button {
  background: var(--accent);
  color: #000;
  border: none;
  padding: 0.6rem 1.5rem;
  font-size: 1.2rem;
  font-weight: 700;
  border-radius: 4px;
  cursor: pointer;
  margin-bottom: 1rem;
}

#start-screen button:hover {
  background: #00cc00;
}

#start-screen p {
  font-size: 1.2rem;
  margin-bottom: 0.5rem;
}

#start-screen small {
  color: #aaa;
}