You can style the visual editor. Simply create your new CSS file – something like editor-style.css and then include the following snippet in your functions
function change_editor_font(){ echo "<style type='text/css'> #editorcontainer textarea#content { font-family: Monaco, Consolas, \"Andale Mono\", \"Dejavu Sans Mono\", monospace; font-size:14px; color:#333; } </style>"; } add_action("admin_print_styles", "change_editor_font");