<h3 class="hover">Hover Me</h3>

.hover {
  --b: 0.1em;   /* the thickness of the line */
  --c: #1095c1; /* the color */
  
  color: #fff;
  padding-block: var(--b);
  background: linear-gradient(red 0 0) 0% var(--_p,0%)/var(--_p,0%) var(--b) no-repeat;
  position: relative;
  transition: .3s var(--_s,0s) linear,background-size .3s calc(.3s - var(--_s,0s));
}
.hover:before {
  content:"";
  position: absolute;
  z-index: -1;
  inset:-100% 0 0;
  background: linear-gradient(var(--c) 50%,#000 0);
  transition: .3s var(--_s,0s) linear;
}
.hover:hover {
  --_p: 100%;
  --_s: .3s;
}
.hover:hover:before {
  transform:translateY(50%);
}

body {
  height: 100vh;
  margin: 0;
  display: grid;
  place-content: center;
}
h3 {
  font-family: system-ui, sans-serif;
  font-size: 3rem;
  margin:0;
  cursor: pointer;
  padding: 0 .1em;
}