FYI - ChatGPT came to the rescue.  The first response it gave me didn’t work, and I told it so.  So it provided another response - and it worked!  For anyone else looking to do this:

In the look and feel:

/* Force FONT NAME on all survey elements */
html, body, .Skin, .Skin * {
 font-family: 'FONT NAME', sans-serif !important;
}

Excellent! Thanks for returning to the community to share what worked!

In order to ensure that all elements are using the correct font-family the Admin > Themes > Style > Custom CSS section will ensure any future surveys will be using the same styling/fonts.

I would recommend removing the !important rule as it isn’t necessary and it will override standard css rules.

For example in your initial code you added the !important to the google font import to ensure the font was applied and the font-weight to 300. While initially it make work, headings <h1 - h6> and bold <b or strong> tags use other font-weights to differentiate themselves.

The following code will work to ensure your Rich Text fields and custom HTML will display correctly. It will also ensure you can embed other custom fonts on sub-elements/questions, otherwise your existing code will overwrite every attempt to change font-family.

/* Imports Roboto Font-Family from Google Fonts (Including Italics and Weights)*/
@import url('https://fonts.googleapis.com/css2?family=Roboto:ital,wght@0,100;0,300;0,400;0,500;0,700;0,900;1,100;1,300;1,400;1,500;1,700;1,900&display=swap');

/* Will default all elements to start with the correct font and weight.*/
* {
 font-family: 'Roboto', sans-serif;
 font-weight: 300;
}

If everything is important, nothing is

~ Patrick M. Lencioni

In order to ensure that all elements are using the correct font-family the Admin > Themes > Style > Custom CSS section will ensure any future surveys will be using the same styling/fonts.

I would recommend removing the !important rule as it isn’t necessary and it will override standard css rules.

For example in your initial code you added the !important to the google font import to ensure the font was applied and the font-weight to 300. While initially it make work, headings <h1 - h6> and bold <b or strong> tags use other font-weights to differentiate themselves.

The following code will work to ensure your Rich Text fields and custom HTML will display correctly. It will also ensure you can embed other custom fonts on sub-elements/questions, otherwise your existing code will overwrite every attempt to change font-family.

/* Imports Roboto Font-Family from Google Fonts (Including Italics and Weights)*/
@import url('https://fonts.googleapis.com/css2?family=Roboto:ital,wght@0,100;0,300;0,400;0,500;0,700;0,900;1,100;1,300;1,400;1,500;1,700;1,900&display=swap');

/* Will default all elements to start with the correct font and weight.*/
* {
 font-family: 'Roboto', sans-serif;
 font-weight: 300;
}

If everything is important, nothing is

~ Patrick M. Lencioni

Thanks for your very detailed guidance, this is really helpful.