Developed a Rustdoc customization feature for the bazelbuild/rules_rust repository, enabling users to inject custom HTML and Markdown CSS into generated documentation. This work extended the existing rustdoc pipeline to support new configuration options, such as html_in_header, html_before_content, html_after_content, and markdown_css, allowing for enhanced branding and contextual content directly within documentation outputs. The implementation required a deep understanding of Rust, rustdoc internals, and Bazel-based build system configuration. By integrating these capabilities, the developer streamlined the documentation process, reducing the need for post-generation modifications and improving the overall user experience for teams relying on automated documentation workflows.