Content and design were refreshed to modernize the guide.
- Rewrites content in Markdown for easier maintenance and removes all _includes for code snippets.
- Rebuilds page layout using CSS Grid.
- Removed outdated JavaScript-generated markup section given the proliferation of numerous JS frameworks.
Remove outdated Prefixed properties section as most of the properties this applied to no longer require prefixes (e.g.,border-radius,box-shadow, etc). - Redesigns masthead and introduces a new project icon.