Extend/fix theme fonts

After reviewing font-size and style assignments to different text categories with Alina, these have been revised and the difference in text options is now more observable and dramatic. These changes will effect text in existing stories, so only merge when ready. 

Also, changes in the other repos have been made along side this, so those pull requests will need to be merged alongside this one. 

These style changes will also need to be reflected in the text element in the composer.