Size of Font on Form

So to increase the font size of the inputs you would add the following to your themes style.css

.gform_wrapper input[type=text], .gform_wrapper input[type=url], .gform_wrapper input[type=email], .gform_wrapper input[type=tel], .gform_wrapper input[type=number], .gform_wrapper input[type=password], .gform_wrapper textarea, .gform_wrapper select {
font-size: 30px;
}

The above will also target and increase the font size in the dropdown select field but if you don't want that to happen just remove this from the above

, .gform_wrapper select

And for future reference if you wanted to increase the size of the name and address field sub labels for example you would use the following

.gform_wrapper .ginput_complex label, .gform_wrapper .gfield_time_hour label, .gform_wrapper .gfield_time_minute label, .gform_wrapper .gfield_date_month label, .gform_wrapper .gfield_date_day label, .gform_wrapper .gfield_date_year label, .gform_wrapper .instruction {
font-size: 20px;
}

Regards,
Richard
--
Just another member of the community helping out where I can

When you first tried to adjust the font size where did you enter the css, it kinda looks like it was entered on the actual page just after the form embed code.