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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "PingFang SC", "Microsoft YaHei", sans-serif;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  background: #1a1a2e;
  color: #fff;
  overflow: hidden;
  touch-action: none;
}

#app {
  width: 100%;
  height: 100vh;
  position: relative;
}

.screen {
  position: absolute;
  top: 0; left: 0;
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  animation: fadeIn 0.4s ease;
}

.hidden { display: none !important; }

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(16px); }
  to { opacity: 1; transform: translateY(0); }
}

/* 开始界面 */
#start-screen {
  background: linear-gradient(135deg, #0f0c29, #302b63, #24243e);
  padding: 20px;
}

#start-screen h1 {
  font-size: 2.8em;
  margin-bottom: 8px;
  text-shadow: 0 4px 12px rgba(0,0,0,0.4);
}

.subtitle {
  color: rgba(255,255,255,0.65);
  margin-bottom: 24px;
  font-size: 1.05em;
}

.rules {
  background: rgba(255,255,255,0.07);
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: 16px;
  padding: 16px 24px;
  margin-bottom: 20px;
  text-align: left;
}

.rules p {
  padding: 5px 0;
  font-size: 0.98em;
  color: rgba(255,255,255,0.8);
}

.high-score-display {
  font-size: 1.1em;
  color: #ffd200;
  margin-bottom: 20px;
}

button {
  padding: 14px 48px;
  font-size: 1.15em;
  font-weight: 700;
  border: none;
  border-radius: 14px;
  background: linear-gradient(135deg, #f7971e, #ffd200);
  color: #1a1a2e;
  cursor: pointer;
  transition: all 0.2s ease;
  box-shadow: 0 6px 20px rgba(247,151,30,0.3);
}

button:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 28px rgba(247,151,30,0.5);
}

button:active { transform: translateY(0); }

/* 游戏界面 */
#game-screen {
  background: #1a1a2e;
}

.hud {
  position: absolute;
  top: 0; left: 0; right: 0;
  display: flex;
  justify-content: center;
  gap: 20px;
  padding: 12px 16px;
  background: rgba(0,0,0,0.5);
  z-index: 10;
  font-size: 1.1em;
  font-weight: 700;
}

.hud-item span {
  color: #ffd200;
}

#game-canvas {
  display: block;
  width: 100%;
  height: 100%;
}

/* 结算界面 */
#result-screen {
  background: linear-gradient(135deg, #0f0c29, #302b63, #24243e);
  text-align: center;
  padding: 20px;
}

#result-icon { font-size: 4em; margin-bottom: 12px; }

#result-title {
  font-size: 1.8em;
  margin-bottom: 12px;
}

#result-score {
  font-size: 1.2em;
  color: rgba(255,255,255,0.8);
  margin-bottom: 8px;
}

#result-record {
  font-size: 1.1em;
  color: #ffd200;
  margin-bottom: 28px;
  min-height: 1.4em;
}