如何使用CSS在圆角边框HTML表格的边缘添加额外的空间

I am trying to add some extra space at the edges of a rounded HTML Table. Here is a picture of what I want to achieve (Notice the extra space on the edges of the table):
https://i.stack.imgur.com/JAm64.jpg
For the extra space on the edges, I tried to add a border with the same colour as the inside, but for some reason, the rounded corners did not come.

Here is my code:

table{
  background-color: #FBF85D;
  border: 25px solid #FBF85D;
  border-radius: 25px;
  box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2), 0 6px 20px 0 rgba(0, 0, 0, 0.19);
}
<table class="board" cellpadding="15px">
  <tr>
      <!-- I am using Bootstrap buttons -->
      <td><button class="btn btn-secondary btn-circle btn-circle-xl"></button></td>
      <td><button class="btn btn-secondary btn-circle btn-circle-xl"></button></td>
      <td><button class="btn btn-secondary btn-circle btn-circle-xl"></button></td>
      <td><button class="btn btn-secondary btn-circle btn-circle-xl"></button></td>
      <td><button class="btn btn-secondary btn-circle btn-circle-xl"></button></td>
      <td><button class="btn btn-secondary btn-circle btn-circle-xl"></button></td>
      <td><button class="btn btn-secondary btn-circle btn-circle-xl"></button></td>
  </tr>
  <tr>
      <td><button class="btn btn-secondary btn-circle btn-circle-xl"></button></td>
      <td><button class="btn btn-secondary btn-circle btn-circle-xl"></button></td>
      <td><button class="btn btn-secondary btn-circle btn-circle-xl"></button></td>
      <td><button class="btn btn-secondary btn-circle btn-circle-xl"></button></td>
      <td><button class="btn btn-secondary btn-circle btn-circle-xl"></button></td>
      <td><button class="btn btn-secondary btn-circle btn-circle-xl"></button></td>
      <td><button class="btn btn-secondary btn-circle btn-circle-xl"></button></td>
  </tr>
</table>