Modal: Add css classes to allow styling through external stylesheets

[bsbeeks]

This should be a fairly straight forward change and should not effect the UI or functionality of the component. It's what we'd consider a "no harm" change. Here's what you need to do:

• Fork the repo
• run npm install
• run npm run demo. This will open up a new browser window with demos of each component. It will refresh whenever you save changes to the files in the src directory.
• open up src/components/Modal
• On line 23, add className='mx-modal' before the style prop declaration.
• On line 24, add className='mx-modal-scrim' before the onClick prop declaration.
• On line 25, add className='mx-modal-content' before the style prop declaration.
• On line 27, add className='mx-modal-close' on it's own line, before the onClick prop declaration.
• Open the demo and make sure your changes didn't break the Modal component.
• run eslint src to check for syntax and style errors. Fix the errors as needed.
• Commit your changes to the src/ directory
• Push your changes to your fork
• Create a PR and include Fixes #31 in the message
• Get merged and celebrate 🎉

[varjmes]

Hi @bsbeeks. I just wanted to take the time to say thank you for this awesome list. It's really encouraging for me (creator of @yourfirstpr) to keep going, and I've scheduled this issue for a tweet for today at 1PM (GMT).

🙏🏼