body {
  margin: 0;
  padding: 0;
  overflow: hidden;
  background: #111;
}

#game-canvas {
  display: block;
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  z-index: 0;
}

#start-screen,
#game-over-screen {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  background: rgba(0, 0, 0, 0.5);
  z-index: 10;
}

.menu-help-btn {
  position: absolute;
  top: 16px;
  right: 16px;
}

#start-screen.hidden,
#game-over-screen.hidden {
  display: none;
}

.btn {
  padding: 15px 40px;
  font-size: 24pt;
  font-family: "Roboto", Arial, sans-serif;
  background: #e67e22;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  margin-top: 20px;
  color: #000;
  font-weight: bold;
  transition: background 0.2s;
}

.btn:hover {
  background: #d35400;
}

h1 {
  color: #fff;
  font-size: 48pt;
  margin-bottom: 10px;
  font-family: "Roboto", Arial, sans-serif;
}

p {
  color: #eee;
  font-size: 18pt;
  font-family: "Roboto", Arial, sans-serif;
}

#score-display {
  position: absolute;
  bottom: 20px;
  left: 0;
  width: 100%;
  display: flex;
  justify-content: space-between;
  padding: 0 40px;
  box-sizing: border-box;
  pointer-events: none;
  z-index: 5;
  color: #fff;
  font-family: "Roboto", Arial, sans-serif;
  font-size: 24pt;
  font-weight: 700;
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.5);
}

#current-score,
#best-score {
  display: inline-block;
}

.help-btn {
  width: 40px;
  height: 40px;
  border: none;
  border-radius: 50%;
  background: rgba(0, 0, 0, 0.45);
  color: #fff;
  font-family: "Roboto", Arial, sans-serif;
  font-size: 22pt;
  font-weight: 700;
  line-height: 1;
  cursor: pointer;
  transition: background 0.2s;
}

.help-btn:hover {
  background: rgba(230, 126, 34, 0.85);
}

#help-screen {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  background: rgba(0, 0, 0, 0.55);
  z-index: 15;
}

#help-screen.hidden {
  display: none;
}

.help-panel {
  position: relative;
  max-width: 420px;
  margin: 0 20px;
  padding: 28px 32px;
  background: #1a1a1a;
  border: 1px solid #333;
  border-radius: 12px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.45);
}

.help-panel h2 {
  margin: 0 0 16px;
  color: #fff;
  font-size: 28pt;
  font-family: "Roboto", Arial, sans-serif;
}

.help-panel p {
  margin: 0 0 10px;
  color: #ddd;
  font-size: 16pt;
  line-height: 1.4;
}

.help-panel p:last-child {
  margin-bottom: 0;
}

.help-close {
  position: absolute;
  top: 10px;
  right: 12px;
  border: none;
  background: none;
  color: #aaa;
  font-size: 28pt;
  line-height: 1;
  cursor: pointer;
  padding: 0;
}

.help-close:hover {
  color: #fff;
}

#final-score {
  font-size: 32pt;
  font-weight: 700;
}