fix: white background when content overflows viewport

[adi-ray]

Fixes #3563

Changes: Changed the height property to allow the container to grow with content while maintaining min-height: 100vh.

Pages verified after this change:

• /about,
• /signup,
• /terms-of-use,
• /privacy-policy,
• /code-of-conduct

I have verified that this pull request:

• has no linting errors (npm run lint)
• has no test errors (npm run test)
• is from a uniquely-named feature branch and is up to date with the develop branch.
• is descriptively named and links to an issue number, i.e. Fixes #123
• meets the standards outlined in the accessibility guidelines

[raclim]

Thanks so much for your interest in this issue and for outlining out your proposed solution and testing process!

This overall looks good to me!