Here you go:
CSS, add this code in the header of your page or anywhere above the button.
1 2 3 4 5 | <style type="text/css"> .btn-huge{ padding:15px 20px 15px 20px; } </style> |
The bootstrap button should look like this:
2 | <button type="submit" name="processAddress" class="button btn btn-huge btn-default button-medium"> |
You can modify the values from css padding to have the button as big as you like.