.mouse-menu
{
  display: none;
  z-index: 1000;
  position: absolute;
  overflow: hidden;
  border: 1px solid #CCC;
  white-space: nowrap;
  font-family: sans-serif;
  background: #FFF;
  color: #333;
  border-radius: 5px;
  padding: 0;
}

  .mouse-menu li
  {
    padding: 8px 12px;
    cursor: pointer;
    list-style-type: none;
    transition: all .3s ease;
    user-select: none;
  }

    .mouse-menu li:hover
    {
      background-color: #DEF;
    }