Improve contrast ratio in contributor card and search results message

[yuanLeeMidori]

Issue This PR Addresses

Fixes: #2049
Fixes: #2168

Type of Change

• Bugfix: Change which fixes an issue
• New Feature: Change which adds functionality
• Documentation Update: Change which improves documentation
• UI: Change which improves UI

Description

Current contributor card in about page (dark mode) doesn't meet AAA rating in WCAG. I change the color to make it meet the requirement.
Before

After

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The messages in search result, "No more posts" and "No results found" has same font and background color, which makes it invisible. I change the font color to make it visible. Please let me know if you have other suggestion of the color choosing, appreciate it.

No more posts

No results found

Checklist

• Quality: This PR builds and passes our npm test and works locally
• Tests: This PR includes thorough tests or an explanation of why it does not
• Screenshots: This PR includes screenshots or GIFs of the changes made or an explanation of why it does not (if applicable)
• Documentation: This PR includes updated/added documentation to user exposed functionality or configuration variables are added/changed or an explanation of why it does not(if applicable)

[izhuravlev]

Good job! You can probably squash those commits and LGTM!

[chrispinkney]

Very nice!