<form>
  <p><input type="text"></p>
  <p><input class="btn-3d" type="submit" value="送信する"></p>
  <p><input class="btn-3d-shadow" type="submit" value="送信する"></p>
</form>

.btn-3d {
  border-bottom: solid 3px gray;
  border-radius: 3px;
}

.btn-3d-shadow {
  border-bottom: solid 3px gray;
  border-radius: 3px;
  box-shadow: 0px 3px 5px lightgray;
}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.