html,
body {
  margin: 0;
  padding: 0;
  width: 100%;
  height: 100%;
  background: #000;
  overflow: hidden;
  font-family: Arial, Helvetica, sans-serif;
}

#game {
  position: relative;
  width: 100vw;
  height: 100vh;
}

canvas {
  display: block;
  width: 100%;
  height: 100%;
}

#game-header {
  position: absolute;
  top: 18px;
  left: 20px;
  right: 20px;
  z-index: 30;
  display: flex;
  justify-content: space-between;
  align-items: center;
  pointer-events: none;
  transition: opacity 0.5s ease;
}

#back-link {
  pointer-events: auto;
  color: rgba(255, 255, 255, 0.72);
  text-decoration: none;
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

#back-link:hover {
  color: rgba(255, 255, 255, 0.95);
}

#header-title {
  color: rgba(255, 255, 255, 0.45);
  font-size: 12px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

#ui {
  position: absolute;
  top: 58px;
  left: 24px;
  z-index: 20;
  color: rgba(255, 255, 255, 0.92);
  pointer-events: none;
}

#title {
  font-size: 24px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  opacity: 0.88;
}

#instruction {
  margin-top: 8px;
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  opacity: 0.58;
}

#score {
  margin-top: 14px;
  font-size: 18px;
  opacity: 0.9;
}