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

body {
  background: #3e2723;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  font-family: Georgia, 'Times New Roman', serif;
  overflow: hidden;
}

#game-container {
  position: relative;
  width: 100%;
  max-width: 1200px;
  aspect-ratio: 16 / 9;
}

#game-canvas {
  width: 100%;
  height: 100%;
  display: block;
  border-radius: 8px;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.5);
}

/* --- HUD Bar --- */
#hud {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 50px;
  display: flex;
  align-items: center;
  padding: 0 20px;
  gap: 20px;
  pointer-events: none;
}

#hud > * {
  pointer-events: auto;
}

#wave-counter, #credits-display {
  color: #f5f0e8;
  font-size: 18px;
  font-weight: bold;
  text-shadow: 1px 1px 2px rgba(0,0,0,0.5);
}

#credits-display {
  color: #ffc107;
}

.hud-btn {
  margin-left: auto;
  padding: 8px 20px;
  background: #5d4037;
  color: #f5f0e8;
  border: 2px solid #8b7355;
  border-radius: 8px;
  font-family: Georgia, serif;
  font-size: 16px;
  font-weight: bold;
  cursor: pointer;
  transition: background 0.2s;
}

.hud-btn:hover {
  background: #795548;
}

/* --- Tower Panel --- */
.panel {
  position: absolute;
  background: #f5f0e8;
  border: 3px solid #8b7355;
  border-radius: 12px;
  padding: 16px;
  min-width: 180px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.3);
  z-index: 10;
}

#panel-title {
  font-size: 18px;
  font-weight: bold;
  color: #3e2723;
  margin-bottom: 8px;
}

#panel-info {
  font-size: 14px;
  color: #5d4037;
  margin-bottom: 12px;
}

#panel-actions {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.panel-btn {
  padding: 6px 12px;
  background: #8b7355;
  color: #f5f0e8;
  border: none;
  border-radius: 6px;
  font-family: Georgia, serif;
  font-size: 14px;
  cursor: pointer;
  transition: background 0.2s;
}

.panel-btn:hover {
  background: #a1887f;
}

.panel-btn:disabled {
  background: #bbb;
  cursor: not-allowed;
}

/* --- Overlay Screens (Menu, Wave End, Win/Lose) --- */
.overlay {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: rgba(62, 39, 35, 0.9);
  color: #f5f0e8;
  z-index: 20;
}

.overlay h1 {
  font-size: 48px;
  margin-bottom: 12px;
  text-shadow: 2px 2px 4px rgba(0,0,0,0.5);
}

.overlay h2 {
  font-size: 36px;
  margin-bottom: 12px;
}

.overlay p {
  font-size: 20px;
  margin-bottom: 24px;
  color: #d7ccc8;
}

.menu-btn {
  padding: 14px 40px;
  background: #8b7355;
  color: #f5f0e8;
  border: 3px solid #d4c5a0;
  border-radius: 12px;
  font-family: Georgia, serif;
  font-size: 22px;
  font-weight: bold;
  cursor: pointer;
  transition: background 0.2s, transform 0.1s;
}

#version {
  margin-top: 20px;
  font-size: 13px;
  color: #8d7b6e;
  letter-spacing: 1px;
}

.menu-btn:hover {
  background: #a1887f;
  transform: scale(1.05);
}