Tweak Me v2 - How to Change the Post Title Font
The post title font settings are in two locations.
1: Font for the homepage and blog archives.
To change how the post title is displayed on the homepage and/or blog archive pages, go to Appearance > Theme Settings, click on "Layouts", followed by the "Blog Archive" link.
Scroll far down to the "Styling" section. The first setting under there is for "Post Title Font". That's where you can adjust the colour, size, and typeface.
2: Font for individual post pages.
There's a separate setting for controlling the font style on individual post pages.
Still in the "Layouts" tab, click the "Single Posts" link at the top.
Scroll down again to the "Styling" section and look for the "Post Title Font" section. That's where you can adjust the style and size for the single post page template.