Website: Make it easier to differentiate component from the background on component pages

[mcarrano]

When viewing component examples, it's sometimes hard to tell what's the component and what's the workspace background. Below is an example:

In this case it's easy to mistaken that example title/heading from the Card header.

Want to identify some styling options to restyle these pages to make it clear what's a component and what's part of the workspace background.

[mcarrano]

@beccaglass I am going to grab this one as part of a larger initiative to make our documentation pages more usable.

[maryshak1996]

Reviewed these designs with @mcarrano and I think that we are comfortable with this design for now.
I've mocked up the component pages in the context of the 'Card component page' and the 'Accordion component page'.
Marvel doc here | Sketch file here

[mcarrano]

I've opened patternfly/patternfly-org#2843 to address both this and the TOC issue and will close this one out. Thanks for your efforts on this @maryshak1996 !