High contrast conditional classes - #2127

Changed pages include:

• index.html - view
• brand/colors/index.html - view
• brand/data-visualization/index.html - view
• brand/logo/index.html - view
• brand/principles/index.html - view
• brand/typography/index.html - view
• brand/copywriting/concepts/index.html - view
• brand/copywriting/naming/index.html - view
• content/examples/alt-text/index.html - view
• content/examples/error-messages/index.html - view

There are more changes not included in the list