How to center multiple buttons in css?

Question

I am a beginner. How can I get those buttons centered in css? Buttons contain svg images. Any help will be appreciated.

#twitter-icon {
  border: none;
  color: none;
  text-decoration: none;
  cursor: pointer;
  display: inline-block;
  backface-visibility: hidden;
  background-color: none;
  width: 0px;
  height: 0px;
  display: inline-block;
  margin-right: 70px;
  margin-top: 150px;
}

#facebook-icon {
  border: none;
  color: none;
  text-decoration: none;
  cursor: pointer;
  display: inline-block;
  backface-visibility: hidden;
  background-color: none;
  width: 0px;
  height: 0px;
  display: inline-block;
  margin-right: 70px;
}

<div class="buttons" id="buttons">
  <button type="button" id="twitter-icon">
        <img src="img/twitter-icon.svg">
    </button>
  <button type="button" id="facebook-icon">
        <img src="img/facebook-icon.svg">
    </button>
</div>

Thank you for your time.