docs: Fix code background-color in dark theme

[saforem2]

Description

Fix code background color in dark theme to match background

Screenshots

Before

After

Related Issue(s)

Type of Change

• Documentation content update (new page, formatting/typo changes, adding more info, etc.)
• Functionality bug fix
• New feature (mkdocs feature, mkdocs-material style changes, HTML/CSS/JS customization, developer or repo tool)

Checklist

• I have run make serve or make build-docs locally and verified that my changes render correctly
• I have added at least one Label to this PR

Copilot Summary

This pull request makes minor adjustments to the alcf-extra.css stylesheet, primarily refining the appearance of inline code blocks and navigation headers.

Styling updates:

• Updated the background and text color for inline code blocks within .md-typeset, improving contrast and readability. The old rule was commented out and replaced with a new one.
• Adjusted the padding for navigation header list items from 9px to 8px for a slightly more compact layout.

Other:

• Removed an unnecessary blank line for minor code cleanliness.

[Copilot]

Pull Request Overview

This PR fixes the code block background color in dark theme to improve visual contrast and readability. The changes update the CSS styling rules to ensure inline code blocks have appropriate colors that match the dark theme background.

• Updated inline code block styling to use darker background with lighter text in dark theme
• Made minor padding adjustment to navigation header list items for better spacing
• Removed unnecessary blank line for code cleanliness

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[saforem2]

@sbx-bnagle I fixed the code background in this if you want to see how it looks

[sbx-bnagle]

@saforem2 Looks good!

[atanikan]

LGTM!