Rebrand in one pass with tokens

Before you change a pixel, check that components use tokens (--primary, text-muted-foreground) and not literal values. Ask the agent to find every hard-coded colour, font and radius and move them to the token sheet. That one refactor is what makes later changes cheap and safe.

Then the rebrand is: new palette with contrast ratios checked, new fonts, one radius, one spacing scale. Review it on three pages (home, a long article, a form) at 390px before rolling out.