First, you click on the Site Styles icon on the right of the Header
Next, you choose Fonts
Scroll down to the bottom and choose Assign Styles
Blog List
You can click on the Heading of Title like below.
And then, click on the Heading 3 of the Size option
Next, you choose Custom
Finally, change to the custom size you want and click Save on the left of the Header
Blog Detail Post
Scroll down a bit and click on Heading of Title – Blog Post
And then, click on the Heading 1 of the Size option
Next, you choose Custom
Finally, change to the custom size you want and click Save on the left of the Header
