body {
  -webkit-user-select: none; /* Safari/Chrome */
  -moz-user-select: none;    /* Firefox */
  -ms-user-select: none;     /* IE/Edge */
  user-select: none;         /* 标准语法 */
}
.protected-content::after {
  content: "";
  position: absolute;
  top: 0; left: 0; 
  width: 100%; height: 100%;
  z-index: 999;
}