How can I change the font size and text background of the text under each photo in a "Summary" section on my website?

Just trying to improve my homepage and the font sizes are too small under each picture in the summary, they're not very eye-catching which is why I also want to add a background color. ultimately to make them look more engaging.

Site: https://mauve-fish-8e4l.squarespace.com/

Password: square123

@hsoweid Add to Home > Design > Custom CSS

.homepage .layout-caption-below .image-caption p {
    font-size: 20px;
}
.homepage .layout-caption-below .image-caption {
    background: #f1f2f3;
}