15 enforceable rules pulled verbatim from the spec
Do
Use Near-Black (`#212529`) for text — not pure black, it's warmer and more readable
Use OpenSans as the primary typeface — it defines the brand personality
Use #004488 (`#004488`) as the primary accent — it's the brand's signature interactive color
Style form inputs with a `1px solid rgb(222, 226, 230)` border — use border-based inputs, not floating labels or underline-only
Maintain nav height at 49px — consistent vertical space for the navigation bar
Respect the 4px–32px spacing range — the design uses a wide scale for visual breathing room
Each card uses an icon (not photo) — the visual language is illustrative, not photographic
Use a 4-column grid on desktop — density matters for this content type
Don't
Don't use pure black (`#000000`) for text — the near-black adds warmth
Don't substitute with generic sans-serif or serif — the custom font carries the brand
Don't introduce additional saturated accent colors — the palette is intentionally controlled
Don't remove the input border — the border is the primary affordance indicator for form fields
Don't collapse or hide the nav on scroll without an explicit scroll-triggered animation — the design uses fixed nav presence
Don't make the nav sticky — this design lets it scroll away to maximize content focus
Don't put a CTA button in the nav — this design uses links only at the top
10
Agent guide & export
Paste-ready prompt + the real files behind this page
Build a UI in the onetonline.org design system.
Canvas #ffffff · ink #212529 · accent #004488.
Type: OpenSans — respect the size/weight ladder in §3.
Radius, spacing, shadow: use only the extracted scales (no magic numbers).
Full spec follows — paste the DESIGN.md below into your agent.