Update the CSS file & fix documentation errors

[adelgadoj3]

The CSS file needs to be updated. In the top right hand corner of the page, similar to how it is displayed on the Micronaut documentation, there should be links to:

• Java docs (placeholder until material is finalized)
• API reference
• Community guidelines
• Contributor License Agreement
• TOC text is now staggered. Text should be aligned as it previously was. (see below)
• Make sure "Improve this doc" is next to the component name which is currently in the next line.
• Some of the "Improve this doc" are pointing to the develop branch, changed it to the main branch.

Optional:
For ease of use in future iterations of this project it may be recommended to re-design the CSS file with proper documentation. This will allow for easier changes and updates to the file.

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