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

html, body {
  height: 100%;
  overflow: hidden;
  background: #0b0f14;
}

#scene {
  display: block;
  width: 100%;
  height: 100%;
}

.back {
  position: fixed;
  top: 16px;
  left: 16px;
  padding: 8px 14px;
  background: rgba(18, 24, 32, 0.85);
  border: 1px solid #1e2833;
  border-radius: 8px;
  color: #e6edf3;
  text-decoration: none;
  font-size: 14px;
  font-family: -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;
  transition: border-color 0.2s;
}

.back:hover {
  border-color: #4da3ff;
}

.hint {
  position: fixed;
  bottom: 16px;
  left: 50%;
  transform: translateX(-50%);
  color: #8b98a5;
  font-size: 12px;
  font-family: -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;
}