SOURCE CODE: Uize.Widgets.Button.Square.Icon.Css (view docs)

.`icon` {
  position: absolute;
  background-position: center center;
  background-repeat: no-repeat;
  background-size: 90%;
}

/*** different sizes ***/
<%
  function _sizeStyleProperties (_sizeNo) {
    var _pos = _sizeNo + 2;
    %>
    left: <%= _pos %>px;
    top: <%= _pos %>px;
    right: <%= _pos %>px;
    bottom: <%= _pos %>px;
    <%
  }
%>
  .`tiny` .`icon` {
    <% _sizeStyleProperties (0) %>
  }

  .`small` .`icon` {
    <% _sizeStyleProperties (1) %>
  }

  .`medium` .`icon` {
    <% _sizeStyleProperties (2) %>
  }

  .`large` .`icon` {
    <% _sizeStyleProperties (3) %>
  }