src/css/fa-icons.css

.doc .admonitionblock .icon {
  border-radius: 1rem;
}

i.fa[class^='icon-'],
i.fa[class*=' icon-']::before {
  content: "";
  height: 1.25rem;
  width: 1.25rem;
  margin-right: 0.25rem;
  margin-left: -0.5rem;
}

i.fa.icon-note::before {
  background: no-repeat url("../img/note.svg");
}

i.fa.icon-tip::before {
  background: no-repeat url("../img/tip.svg");
}

i.fa.icon-important::before {
  background: no-repeat url("../img/important.svg");
}

i.fa.icon-warning::before {
  background: no-repeat url("../img/warning.svg");
}

i.fa.icon-caution::before {
  background: no-repeat url("../img/caution.svg");
}