Multi Column form for a checklist box Questionnaire

Site URL: https://www.kristinelizabethmua.com/covid19questionnaire

Hi! I have a questionnaire that I have to send to my clients for them to fill before they're able to receive services & it has a few checklist box items and I was wondering if there was any type of code or design that I could input in my site to make that happen. So far I haven't been able to figure anything out and I'm not entirely sure where to even be putting it. 

I tried a code I found in the forum, but 1. it didn't work and 2. I kept getting a syntax error in my custom code, so I'm assuming I'm going to need to use a code box. I've attached a screenshot of the checklist items in the questionnaire. 

The link is HERE

Thank you in advance for all of your help! Y'all are literally the best!

Warmly,

Kristin

You mean like this?

YES @tuanphan  that's exactly it!

@tuanphan where/how do I implement code to update my form like that? And does it just apply to those checklist items or anything below that line? Thank you so much for your help. I've been trying to figure this out and I just can't seem to get this one.

Add to Page Settings > Advanced > Header

<style>
  @media screen and (min-width:901px) {
  fieldset:nth-child(n+8) {
    width: 30% !important;
    float: left !important;
}
    .form-item:nth-child(n+18) {
    clear: left !important;
    width: 100% !important;
}
  }
</style>