Change font size on blog title

I found a custom CSS here to change the font size on my blog page, but it did not work. Can anyone offer me assistance with this? I am really not tech savvy and have looked everywhere and tried everything I could to change the font size of the title on the blog page (not individual blogs). I need to make the title smaller so that it reflects the size of the blog titles on the home page. That when I post blogs with longer titles they line up correctly on the page with the masonry (grid style) layout I am using. Please help!!! Or if there’s another way to go about this I am open to that as well.

Hopefully, I was clear.

Here is my website:

Hello there,

Thank you for reaching out to us here.

To change it to look as small as the latest news widget, apply the following CSS code into your site’s additional CSS option which resides under the Appearance > Customize > Additional CSS.

.hentry .title-post {
   font-size: 16px;