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>
console
<div class="d1"></div>
.d1 {
  width: 50%;
  height: 100px;
  background: #eee;
  user-select: none;
  margin: 0 auto 50px auto;
  position: relative;
}

.d1::after {
  content: '';
  border-bottom: 2px solid #107ed8;
  width: 0;
  position: absolute;
  bottom: 0;
  left: 100%;
  transition: width .35s, left .35s;
}
.d1:hover::after {
  left: 0;
  width: 100%;
  transition: width .35s;
}