These are the custom field settings, btw.
Font size
Choose your preferred font size. Examples of valid input are "14px" and "100%".
/^[0-9]{1,3}(\.[0-9]{1,2})?(em|pt|px|%)$/
To me it'd be more efficient and much more powerful to just have a custom CSS field, but this way it's easy to understand for everyone.
Another thing in there is some beloved (by one member in any case 
) SMF bb codes:
public static function bbc_codes(&$codes, &$no_autolink_tags, &$itemcodes)
{
$codes[] = array(
'tag' => 'glow',
'type' => 'unparsed_commas',
'test' => '[#0-9a-zA-Z\-]',
'before' => '<span style="text-shadow: $1 0 0 4px">',
'after' => '</span>',
);
$codes[] = array(
'tag' => 'shadow',
'type' => 'unparsed_commas',
'test' => '[#0-9a-zA-Z\-]{3,12},(left|right|top|bottom|[0123]\d{0,2})\]',
'before' => '<span style="text-shadow: $1 $2">',
'after' => '</span>',
'validate' => function(&$tag, &$data, $disabled)
{
if ($data[1] == 'top' || (is_numeric($data[1]) && $data[1] < 50))
$data[1] = '0 -2px 1px';
elseif ($data[1] == 'right' || (is_numeric($data[1]) && $data[1] < 100))
$data[1] = '2px 0 1px';
elseif ($data[1] == 'bottom' || (is_numeric($data[1]) && $data[1] < 190))
$data[1] = '0 2px 1px';
elseif ($data[1] == 'left' || (is_numeric($data[1]) && $data[1] < 280))
$data[1] = '-2px 0 1px';
else
$data[1] = '1px 1px 1px';
},
);
}
Of course there's also the pictureFill JS:
// Add Picturefill for DnD logo
addInlineJavascript('
// Picture element HTML5 shiv
document.createElement(\'picture\');', true);
loadJavascriptFile('picturefill.min.js', array('async' => true));
And besides some other minor adjustments to $context['html_headers'] and $forum_copyright, one ultimate edit through integrate_buffer. That way the source files are all vanilla Elk, which I love 'cause that way I don't have to worry about anything. 
Right, sorry, totally off topic. But Elk rocks! 
Modern, Free, Powerful