<div class="container">
  <a class="btn-surround" href="#">
    <span>PUSH ME</span>
  </a>
</div>
/* ここはコピーしなくてOK */
.container {
  @import url('https://fonts.googleapis.com/css2?family=Noto+Sans+JP:wght@700&display=swap');
  font-family: 'Noto Sans JP', sans-serif;
  text-align: center;
  padding-top: 40px;
}

/* ここから下がボタンのCSS */
.btn-surround {
  display: inline-block;
  text-decoration: none;
  color: #FFF;
  font-weight: 700;
  background-color: #65A04D;
  text-align: center;
  width: inherit;
  min-width: 250px;
  padding: 16px 16px;
  position: relative;
  opacity: 1 !important;
  transition: all 0.3s;
}
.btn-surround:before,
.btn-surround:after {
  content: "";
  display: block;
  position: absolute;
  background-color: #65A04D;
  top: 0;
  pointer-events: none;
}
.btn-surround:before {
  left: 0;
  width: 0;
  height: 2px;
}
.btn-surround:after {
  right: 0;
  width: 2px;
  height: 0;
}
.btn-surround:hover {
  background-color: #FFF;
  color: #65A04D;
}
.btn-surround:hover:before {
  width: 100%;
  transition: width 0.2s 0.2s;
}
.btn-surround:hover:after {
  height: 100%;
  transition: height 0.1s 0.4s;
}
.btn-surround:hover span:before {
  width: 100%;
  transition: width 0.2s 0.5s;
}
.btn-surround:hover span:after {
  height: 100%;
  transition: height 0.1s 0.7s;
}
.btn-surround span:before,
.btn-surround span:after {
  content: "";
  display: block;
  position: absolute;
  background-color: #65A04D;
  bottom: 0;
  pointer-events: none;
}
.btn-surround span:before {
  right: 0;
  width: 0;
  height: 2px;
}
.btn-surround span:after {
  left: 0;
  width: 2px;
  height: 0;
}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

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