Styling titles in blog content block

Site URL: https://sprout-tuna-swnf.squarespace.com

On my site homepage I have a block that shows, titles and excerpts of my blog. I'm trying to style the titles, and have been able to make some changes to the style, such as color and weight, using the CSS selector "a.summary-title-link " - however when I try to change the size of the title, it doesn't respond. Does anyone know what I need to do to adjust this?

The page is https://sprout-tuna-swnf.squarespace.com/ the section I'm trying to change are the titles under "Projects" halfway down the homepage

Use this CSS

a.summary-title-link {
    font-size: 1em !important;
    font-weight: bold;
    color: #343637;
}