create-theme

# Create a theme A theme is a house style that workbooks link to with `meta.theme`. It lives as markdown so it is readable by both people and agents. ## The file `themes/<id>.md`: ```markdown --- name: corporate-neutral description: Near-white, one blue accent, sans throughout. --- # Corporate neutral ## Palette | Token | Value | Used for | | --- | --- | --- | | ink | #0f172a | body text, table header fill | | accent | #1d4ed8 | KPI values, data bars | | band | #f8fafc | total rows, key-value fills | | rule | #cbd5e1 | hairlines | ## Formats Currency `#,##0` · Percent `0.0%` · Dates `yyyy-mm-dd` ## Paste-ready design const ```tsx export const design: DesignSystem = { … } ``` ## Conventions - Assumptions always on their own sheet, key-value - Data bars on the primary magnitude column only - Column widths: labels 24, figures 14 ``` Optionally add `themes/<id>.demo.tsx` — a small workbook exercising the theme, so the gallery has something to show. ## Rules that matter for print and Excel alike - **One accent colour.** A second one competes; a third is decoration. - **White or near-white background.** Anything darker costs toner and makes Excel's own selection highlight unreadable. - **Body text no smaller than 10pt.** Spreadsheets get printed and squinted at. - **Number formats are part of the theme.** A house style that leaves ratios unformatted has not done its job. - Keep the `design` const a plain object literal so the Design panel can rewrite it.