In the Better Proposals editor, you have the option of adding plain text blocks or feature blocks.
Plain text blocks will only display black fonts, unless you want to edit the HTML directly. However, if you add a feature block you can play with font colour to your heart's content as both the background and text colour can be changed.
Note: A feature block with a white background and dark text will appear exactly like a plain text block in a proposal.
Step 1: Choose a feature block with the green Add To This Page icon.
Step 2: Once you have added the Feature Block, click on it. The options for font colour can be found by clicking on the settings icon.
Step 3: Change your background and text colour to any HEX value you like, then click Save and Update. Here we turned the background of the Feature block a dark green, and selected white for the text:
Here's how it would look in the proposal:
Note: Here we added a second Feature block underneath the first. With a white background, a Feature block displays exactly like a plain block of text, but you can change the text colour - here it is the same dark green as the background of the block above.