Feat: Change color of table headers in light mode

[MaximilianSoerenPollak]

📌 Description

Fixes #529

"Black" text is not possible, as the css selector of the table captions is shared with the nav elements. If we make it black you can not read the nav elements anymore.
=> Now looks like:

🚨 Impact Analysis

• This change does not violate any tool requirements and is covered by existing tool requirements
• This change does not violate any design decisions
• Otherwise I have created a ticket for new tool qualification

✅ Checklist

• Added/updated documentation for new or changed features
• Added/updated tests to cover the changes
• Followed project coding standards and guidelines

[github-actions]

License Check Results

🚀 The license check job ran with the Bazel command:

bazel run --lockfile_mode=error //src:license-check

Status: ⚠️ Needs Review

Click to expand output

[License Check Output]
Extracting Bazel installation...
Starting local Bazel server (8.4.2) and connecting to it...
INFO: Invocation ID: f9f4d971-62bf-4549-820b-1220edf642ea
Computing main repo mapping: 
Loading: 
Loading: 0 packages loaded
Loading: 0 packages loaded
WARNING: Target pattern parsing failed.
ERROR: Skipping '//src:license-check': no such target '//src:license-check': target 'license-check' not declared in package 'src' defined by /home/runner/work/docs-as-code/docs-as-code/src/BUILD
ERROR: no such target '//src:license-check': target 'license-check' not declared in package 'src' defined by /home/runner/work/docs-as-code/docs-as-code/src/BUILD
INFO: Elapsed time: 4.922s
INFO: 0 processes.
ERROR: Build did NOT complete successfully
ERROR: Build failed. Not running target

[github-actions]

The created documentation from the pull request is available at: docu-html

[MaximilianSoerenPollak]

#535 fixes this issue already.