Add subhead/one line of body text to the thumbnails of the portfolio page

Hi! Does anyone know how to add a line of text underneath the title text of the thumbnail images on the portfolio page. There is no space to do this in the individual project settings (which is where the title text populates from). Not sure if this is possible?

I'm not familiar with anything but Custom CSS so adding any code feels a bit dubious, but I'm willing to try if it's considered simple for a beginner. I can't share the site URL because it's for a client and unpublished. There are screenshots attached of what I'm talking about indicating where the ask to add a line of body text is. 

Thanks so much in advance for help/advice/pointing in the right direction.

Can you share link to Porfolio Page? We can give the code to achieve this

Unfortunately the site is not published yet. Will adding custom code make my client ineligible to receive squarespace support if she needs it in future? She will not have me on retainer so any future content updates will be made by her.

I was able to get permission to publish the site from the client. Here is the portfolio page https://fuchsia-celery-4wtw.squarespace.com/brand-strategy-insight

Will adding custom code make my client ineligible to receive squarespace support if she needs it in future? She will not have me on retainer so any future content updates will be made by her.


 @tuanphan thank you!! 

22 hours ago, hecinthecity said:

I was able to get permission to publish the site from the client. Here is the portfolio page https://fuchsia-celery-4wtw.squarespace.com/brand-strategy-insight

 

Will adding custom code make my client ineligible to receive squarespace support if she needs it in future? She will not have me on retainer so any future content updates will be made by her.


 @tuanphan thank you!! 

Add to Design > Custom CSS

a.grid-item[href="/brand-strategy-insight/project-one-5kysf"] h3:after {
    content: "adidas sub";
    display: block;
    font-size: 18px;
}
a.grid-item[href="/brand-strategy-insight/project-two-tj33s"] h3:after {
    content: "Foot sub";
    display: block;
    font-size: 18px;
}
a.grid-item[href="/brand-strategy-insight/project-three-fj3xd"] h3:after {
    content: "Dr.Martens sub";
    display: block;
    font-size: 18px;
}

@tuanphan thanks so much I will give this a try!