I was using the jqGrid (4.5.2) in one of my html web resources for CRM 2011. To adjust the font size of the td of the jqGrid table, we can set the value for the following style element in ui.jqgrid.css style sheet
Or we can using the following style in the html page where we are using the jqGrid
.ui-widget-content td {font-size:1.1em;}
Hope it helps.