/* 物理弹跳小球 - 复刻参考图样式 */
.bounce-physics-ball {
  position: fixed;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  cursor: grab;
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
  z-index: 99999;
  user-select: none;
  touch-action: none;
  background-color: transparent; /* 强制背景透明 */
}
.bounce-physics-ball:active {
  cursor: grabbing;
}
.bounce-floating-tip {
  position: fixed;
  background: #ffd966;
  color: #2c3e50;
  padding: 6px 12px;
  border-radius: 40px;
  font-size: 13px;
  font-weight: bold;
  box-shadow: 0 3px 8px rgba(0,0,0,0.2);
  z-index: 10000;
  cursor: pointer;
  border: 1px solid #fff;
  white-space: nowrap;
  animation: fadeIn 0.2s ease;
}
@keyframes fadeIn {
  from { opacity:0; transform:translateY(4px) }
  to { opacity:1; transform:translateY(0) }
}