丸くて立体的な赤色ボタンです（ホバーでアニメーションあり）

<div class="push-button_box">
  <a href="#" class="push-button">PUSH!</a>
</div>

.push-button_box{
  margin:50px auto;
  width:30%;
}
.push-button {
  display: inline-block;
  background-color: #d60000;
  color: #fff;
  font-weight: bold;
  font-size: 1.5rem;
  text-decoration: none;
  padding: 16px 40px;
  border-radius: 999px;
  position: relative;
  box-shadow: 0 8px 0 #a10000;
  transition: all 0.1s ease;
  text-align: center;
  width: 100%;
}

.push-button:hover {
  transform: translateY(4px);
  box-shadow: 0 4px 0 #a10000;
}