I have a JavaScript API guide that already covers the technical details well, yet its Introduction and Overview still need a thorough sweep for grammar and spelling. Everything must conform to American English conventions—no British variants or mixed usage. You will receive the source files in Markdown. I simply want the language tightened and any typos or punctuation slips fixed; the code blocks and method reference tables should stay untouched unless you spot a clear typo inside a comment or string. Deliverables: • One copy with tracked changes or inline comments so I can see exactly what was edited. • One clean, publication-ready copy. Acceptance criteria: zero grammar or spelling errors remain, terminology is consistent across the edited sections, and formatting is preserved. A quick turnaround is appreciated, but accuracy takes priority.