message: fix(theme): fix page nav icon
diff: transition: border-top var(--color-transition);
  }
  - .prev .icon,
  - .next .icon {
  + .prev-icon,
  + .next-icon {
  position: relative;
  top: 0.125em;
  width: 1em;
  color: var(--theme-color);
  }
  + .nav-link .icon {
  + margin-right: 0.25em;
  + }
  +
  .next {
  float: right;
  }
  