Hi,
Add a html id to your footer block and use that to address your css.
To change the css of your dynamic text you can add this to your custom stylesheet
#YOUR-ID span.acym_dynamic.mceNonEditable {
font-size: 20px !important;
}
You can use the same principle for your other css styling. In case you need to find the selectors used by Acymailing you can view the block's htm with the button just below the html-id you entered.