/* Hover 边线流动 */

.hoverDrawLine {
  border: 0 !important;
  position: relative;
  border-radius: 5px;
  --border-color: #60daaa;
}
.hoverDrawLine::before,
.hoverDrawLine::after {
  box-sizing: border-box;
  content: '';
  position: absolute;
  border: 2px solid transparent;
  border-radius: 5px;
  width: 0;
  height: 0;
}
.hoverDrawLine::before {
  top: 0;
  left: 0;
  -webkit-transition: height 0.25s ease-out 0.5s, width 0.25s ease-out 0.75s,
    border-color 0s ease-in-out 1s;
  transition: height 0.25s ease-out 0.5s, width 0.25s ease-out 0.75s,
    border-color 0s ease-in-out 1s;
}
.hoverDrawLine::after {
  bottom: 0;
  right: 0;
  -webkit-transition: height 0.25s ease-out 0s, width 0.25s ease-out 0.25s,
    border-color 0s ease-in-out 0.5s;
  transition: height 0.25s ease-out 0s, width 0.25s ease-out 0.25s,
    border-color 0s ease-in-out 0.5s;
}

.hoverDrawLine:hover::before,
.hoverDrawLine:hover::after {
  width: 100%;
  height: 100%;
}
.hoverDrawLine:hover::before {
  border-top-color: var(--border-color);
  border-right-color: var(--border-color);
  -webkit-transition: width 0.25s ease-out, height 0.25s ease-out 0.25s;
  transition: width 0.25s ease-out, height 0.25s ease-out 0.25s;
}
.hoverDrawLine:hover::after {
  border-bottom-color: var(--border-color);
  border-left-color: var(--border-color);
  -webkit-transition: width 0.25s ease-out 0.5s, height 0.25s ease-out 0.75s;
  transition: width 0.25s ease-out 0.5s, height 0.25s ease-out 0.75s;
}

<div class="hoverDrawLine"></div>