.border_icon {
  cursor: pointer;
  padding: 10px 20px;
  background: white;
  font-size: 28px;
  border-top-right-radius: 10px;
  border-bottom-left-radius: 10px;
  transition: all 1s;
}
.border_icon:after, .border_icon:before {
  content: " ";
  width: 10px;
  height: 10px;
  position: absolute;
  border: 0px solid #fff;
  transition: all 1s;
}
.border_icon:after {
  top: -1px;
  left: -1px;
  border-top: 5px solid black;
  border-left: 5px solid black;
}
.border_icon:before {
  bottom: -1px;
  right: -1px;
  border-bottom: 5px solid black;
  border-right: 5px solid black;
}
.border_icon:hover {
  border-top-right-radius: 0px;
  border-bottom-left-radius: 0px;
}
.border_icon:hover:before, .border_icon:hover:after {
  width: 100%;
  height: 100%;
}