Hi all,
I am constructing my survey (its an important one!) on Limesurvey which has been purchased via my Uni, so I think the limesurvey I am dealing with is different to if I were to purchase the subscription now myself. However, poor uni student, using my Uni's access is all that is available to me. I am having difficulty in navigating this platform, because it seems that I can't change font size across all questions (I have over 150 questions, it will take me sooo long to go through 1 by 1 to change font size). I would also like to make ALL questions mandatory, but do not know if it is possible to do either of these things without doing it question by question? I will attach a picture of what I see in 'theme' section, but I can see that other people have been able to do this by altering themes. 

I think I am restricted to using my Unis specific template. 

Regarding the font-size, etc., it is not done in the survey theme options. You will need to extend the theme and modify the custom.css file. www.limesurvey.org/manual/New_Template_System_in_LS3.x

Regarding mandatory questions, click on "List questions" in the left panel. After selecting questions, there is a dropdown at the bottom to perform bulk actions.

Thanks a bunch! I have another question.... my survey times out if I am inactive for around 10 minutes, is there a way to change this so the survey can be completed over time, without creating an account? Thanks!

survey times out if I am inactive for around 10 minutes, is there a way to change this so the survey can be completed over time, without creating an account? Thanks!

The session expiration is controlled via the PHP settings. So it depends on your hosting environment and is not controlled via LimeSurvey settings.
www.php.net/manual/session.configuration...ssion.gc-maxlifetime