I built a Markdown resume builder for the AI-paste workflow — here's everything that broke

There's a workflow that basically didn't exist three years ago and now half the job-seekers I know use it: ask ChatGPT, Claude, Gemini, or any AI to write your resume bullets, get back beautifully structured text… and then spend forty minutes mangling it into Word or a drag-and-drop resume builder, fixing bullet indentation and font sizes by hand. Here's the thing that bugged me: LLMs already speak Markdown. Ask any chatbot for a resume and you get ## Experience , **Senior Engineer** , - Shipped X — clean, structured Markdown. Then every resume tool on earth makes you throw that structure away and re-enter it into form fields. So I built ResumeMD: a split-pane editor where you paste Markdown on the left, see a typeset resume on the right, pick a template, and download a PDF. No signup to start, everything in localStorage by default. This post is about the parts that fought back. Decision 1: Markdown is the source of truth Most resume builders store your resume as a proprietary JSON blob mapped to form fields. I wanted the document itself to be portable text. That means the entire product is "just" a Markdown renderer with opinions: h2 = section headers (Experience, Education) — these get the decorative treatment per template: uppercase, border, background, prefix glyphs. h3 = job titles — plain, bold, primary color. One weird trick I'm genuinely fond of: the sidebar template splits a single Markdown document into main column and sidebar using an HTML comment ( <!-- sidebar --> ) as the split marker. Content above the marker is the main column; below is the sidebar. It keeps the document valid Markdown everywhere else. The preview is react-markdown + remark-gfm with a 300ms debounce, styled by a template system that turned out to need three parallel implementations of every template: CSS classes for the live preview, inline-style functions shared between preview and template cards, and pure-JS styles for the PDF renderer. Thirty-two templates, three layers each. When