#content{
opacity: 0.65;
}
#post_detail a {
  position: relative;
  text-decoration: none;
  color: #00fff7;
}
#post_detail a::after {
  content: '';
  position: absolute;
  width: 100%;
  transform: scaleX(0);
  height: 2px;
  top: 100%;
  left: 0;
  background-color: #0087ca;
  transform-origin: bottom right;
  transition: transform 0.5s cubic-bezier(0.22, 0.61, 0.36, 1);
}
#post_detail a:hover::after {
  transform: scaleX(1);
  transform-origin: bottom left;
}