Usually the last font style you choose for your title and paragraph text blocks are the last one saved. So when you add a new title or paragraph text block, the text will be in the last chosen font style.
Copy/paste your font style
If you'd like to copy/past your font styles, you just need to type ⇧+⌘+C to copy the style, then ⇧+⌘+V to paste them to another text block. For our PC friends, just replace "⌘" by "Ctrl" to experience the same magic 🌟