Роман Дворянов

.nav {
  ...
  left: -320px;
}

.nav-toggle {
  ...
  left: 320px;
}

.nav {
  ...
  right: -320px;
}

.nav-toggle {
  ...
  right: 320px;
}

.elem {
  ...
  position: relative;
}

.elem::before {
  content: '';
  display: block; 
  height: 100%;
  padding-top: 100%;
}

<table class="table">
  <tbody>
    <tr>
      <td></td>
      <td></td>
    </tr>
  </tbody>
</table>

<table class="table table-striped">
  <tbody>
    <tr>
      <td></td>
      <td></td>
    </tr>
  </tbody>
</table>

<table class="table table-bordered">
  <tbody>
    <tr>
      <td></td>
      <td></td>
    </tr>
  </tbody>
</table>

<table class="table table-hover">
  <tbody>
    <tr>
      <td></td>
      <td></td>
    </tr>
  </tbody>
</table>

<table class="table table-condensed">
  <tbody>
    <tr>
      <td></td>
      <td></td>
    </tr>
  </tbody>
</table>