About "rigid" div

[ManasN]

Hello, I am thinking of using Unsemantic for my next big project. But before I proceed, I need to know the following:

How can I create three divs (33.33% wide both) or any combination which stays the same way no matter how small the screen becomes while keeping other divs unaffected?

[nathansmith]

<div class="grid-container">

  <div class="grid-33 tablet-grid-33 mobile-grid-33">
    This is always 33%
  </div>

  <div class="grid-33 tablet-grid-33 mobile-grid-33">
    This is always 33%
  </div>

  <div class="grid-33 tablet-grid-33 mobile-grid-33">
    This is always 33%
  </div>

</div>

[ManasN]

Thanks a lot :) Unsemantic is such a great tool I am to loving it more and more each day!