* {
  font-family:  sans-serif;
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  background: #262626;
}
a {
 position: absolute;
 top: 50%;
 left: 50%;
 transform: translate(-50%,-50%);
 padding: 15px 30px;
 text-transform: uppercase;
 text-decoration: none;
 color: #fff;
 letter-spacing: 2px;
 font-size: 20px;
}

a::before{
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: #03e9f4;
  z-index: -1;
  transition: transform 0.5s;
  transform-origin: bottom right;
  transform: scale(0);
}
a:hover::before{
  transition: transform 0.5s;
  transform-origin: top left;
  transform: scale(1);
}

a::after{
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: transparent;
  border: 2px solid #fff;
  box-sizing: border-box;
  z-index: -1;
  transition: transform 0.5s;
  transform-origin: top left;
  transform: scale(1);
}

a:hover::after{
  transition: transform 0.5s;
  transform-origin: bottom right;
  transform: scale(0);
}