Html 如何在一个div中心字体图标

body {
  background-color: #333;
  font-size: 1.5em;
  padding: 0;
}

.buttons {
  display: flex;
  gap: 25px;
  justify-content: center;
  align-items: center;
  text-align: center;
  line-height: 50px;
  vertical-align: bottom;
  float: center;
}

.button {
  padding 5px;
  font-size: 20px;
  color: black;
  height: 50px;
  width: 50px;
  border: 15px solid #2b2b2b;
  background-color: #2b2b2b;
  border-radius: 100%;
  transition: all ease-in-out 0.5s;
}

.button:hover {
  transform: scale(1.1) rotate(360deg);
  box-shadow: 0 0 15px #111;
  cursor: pointer
}

.button:active {
  animation: clicked ease 0.25s
}

@keyframes clicked {
  from {
    background-color: #2b2b2b;
    border: 15px solid #2b2b2b;
    scale: 1;
  }
  to {
    background-color: #333;
    border: 15px solid #333;
    scale: 1.05;
  }
}

<div class="buttons">
  <div class="button"><i class="fa fa-fw fa-dice fa-2xl"></i></div>
  <div class="button"><i class="fa fa-fw fa-code fa-2xl"></i></div>
  <div class="button"><i class="fa fa-fw fa-smile fa-2xl"></i></div>
</div>

<script src="https://kit.fontawesome.com/4fc295af45.js" crossorigin="anonymous"></script>