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

html, body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: #87ceeb;
  font-family: 'Segoe UI', Arial, sans-serif;
}

canvas {
  display: block;
}

#hud {
  position: fixed;
  top: 16px;
  left: 16px;
  color: #fff;
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.5);
  font-size: 22px;
  font-weight: bold;
  z-index: 10;
  user-select: none;
}

#highscore {
  font-size: 16px;
  opacity: 0.9;
  margin-top: 4px;
}

#instructions {
  position: fixed;
  bottom: 16px;
  left: 50%;
  transform: translateX(-50%);
  color: #fff;
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.5);
  font-size: 14px;
  z-index: 10;
  user-select: none;
}

#game-over {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: rgba(0, 0, 0, 0.55);
  color: #fff;
  text-align: center;
  z-index: 20;
}

#game-over h1 {
  font-size: 48px;
  margin-bottom: 12px;
}

#game-over p {
  font-size: 18px;
  margin-top: 6px;
}

.hidden {
  display: none !important;
}