Writes a sticky top bar (a link per data-type group) and a numbered two-column contents list: variable number and name on the left, its label on the right, grouped by data type. Call inside a `results = "asis"` chunk.
Arguments
- groups
A named list of DGF subsets, as returned by [rail_groups()]. Empty groups are skipped.
- brand
Text for the top bar. Defaults to `"Research Guide"`.
- glimpse
Characters of example data to show under each variable's label: the stabilized first values (`stable_first5`), or the preview values for a variable the stabilizer leaves alone. Whole values only — the glimpse stops before the value that would break the budget rather than cutting it — so the count varies by how long they are. `0` leaves the data out. Defaults to `48`.