.btn-one {
  color: #FFF;
  transition: all 0.3s;
  position: relative;
}

.btn-one span {
  transition: all 0.3s;
}

.btn-one::before {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
  opacity: 0;
  transition: all 0.3s;
  border-top-width: 1px;
  border-bottom-width: 1px;
  border-top-style: solid;
  border-bottom-style: solid;
  border-top-color: rgba(255,255,255,0.5);
  border-bottom-color: rgba(255,255,255,0.5);
  transform: scale(0.1, 1);
}

.btn-one:hover span {
  letter-spacing: 2px;
}

.btn-one:hover::before {
  opacity: 1;
  transform: scale(1, 1);
}

.btn-one::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
  transition: all 0.3s;
  /*background-color: rgba(255,255,255,0.1);*/
}

.btn-one:hover::after {
  opacity: 0;
  transform: scale(0.1, 1);
}