SOURCE CODE: Uize.Widgets.Buttons.Char.Css (view docs)

<%@
  required ('Uize.Widgets.CssUtil');
%><%
  var
    _cssUtil = Uize.Widgets.CssUtil,
    _boxBorderWidth = _cssUtil.box.border.width
  ;
%>.`text` {
  position: absolute;
  left: 0;
  top: 0;
  right: 0;
  bottom: 0;
  text-align: center;
  font-size: bold;
}

/*** styling for different sizes ***/
<%
  Uize.forEach (
    _cssUtil.sizes,
    function (_size,_sizeName) {
      var
        _sizeOuter = _size.outer,
        _widthHeight = _sizeOuter - _boxBorderWidth * 2
      ;
      %>.`<%= _sizeName %>` {
        font-size: <%= _widthHeight * .75 %>px;
        line-height: <%= _widthHeight %>px;
      }

      .`<%= _sizeName %>`.`doubleChar` {
        font-size: <%= _widthHeight * .55 %>px;
      }<%
    }
  );
%>