Any button, input[type="button"], input[type="submit"] and .button-sq will be styled by defalut like this:
<button>Button</button>
<input type="button" value="Button">
<input type="submit">
In button-sq.variables file, you will find the variables that change default button styling.
You use .small-sq class.
Small Button
<a href="" class="button-sq small-sq">Small Button</a>
You use .see-through-sq class
See Through Button See Through Small Button
<a href="" class="button-sq see-through-sq">See Through Button</a>
<a href="" class="button-sq small-sq see-through-sq">See Through Small Button</a>
You use .link-sq class.
Link Button Link Small Button
<a href="" class="button-sq link-sq">Link Button</a>
<a href="" class="button-sq small-sq link-sq">Link Small Button</a>
For other particular styles you can use the following classes:
<a href="" class="button-sq cancel-sq">Cancel Button</a>
<a href="" class="button-sq facebook-button"><i class="icon icon-logo-facebook2"></i>Facebook Button</a>
<a href="" class="button-sq google-button"><i class="icon icon-logo-circle-google-plus-22"></i>Google Button</a>