Change theme colors

[kprosise]

Marketing requested change to the colors of the expand icon and the section headers in the sidebar.

Testing: Viewed rendered output in browser. No changes made to links or content.

This commit has no associated issue, quick fix.

PR Template and Checklist

Please complete as much as possible to speed up the reviewing process.

Readiness and adding reviewers as appropriate is required.

All PRs should be reviewed by a technical writer/documentation team and a peer.
If effecting customers—which is a majority of content changes—a member of Customer Success must also review.

Readiness

• Merge (pending reviews)
• Merge after date or event
• Draft

Overview

Minor tweaks to the theme.

Checklist

• Match tone and style of page/section.
• View HTML in a browser to check rendering.
• follow best practices for commits.
  • Descriptive title written in the imperative.
  • Include brief overview of QA steps taken.
  • Mention any related issues numbers.
  • End message with sign off/DCO line (-s, --signoff).
  • Sign commit with your gpg key (-S, --gpg-sign).
  • Squash commits if needed.
• Request PR review by a technical writer and at least one peer.

Comments

Any thing else that a maintainer/reviewer should know.
This could include potential issues, rational for approach, etc.

[doanac]

Docs for 3a0cc2a are browsable at: https://ci.foundries.io/projects/fio-docs/builds/2769/docs/artifacts/html/index.html