01
The three surfaces
- Visual editor — approximate WYSIWYG on the left. Good for headings, lists, and clicking into formulas. It is not the PDF.
- Code editor — the
.texsource. Exact commands, packages, and comments. - PDF viewer — the compiled document. This is what print and download look like.
If something “didn’t show,” check which surface you are looking at. The PDF viewer is appearance truth.