Analysis of GitHub's Primer Design SystemAnalysis of GitHub's Primer Design System

I reverse-engineered GitHub's Primer design system to learn how a mature one is actually built. Working in three phases — interface inventory, foundations, and component architecture — I rebuilt key parts in Figma, using local variables to wire tokens, states, and themes together. The point was to see, firsthand, how Primer holds up across contexts and color modes.

I like how Primer looks and how it behaves, and I wanted to learn from a real production system instead of theorizing about one. Rebuilding it in Figma was the most direct way to study how decisions, tokens, and reuse get structured at that scale. It also forced me to get sharper at Figma variables for dark/light, states, and variants.

I started with a UI audit across GitHub's product, pulling out the core elements — buttons, links, inputs, nav — and documenting how each one looks, how its states change, and how it shifts between themes. The audit gave me a baseline of what was actually in the system before I tried to rebuild any of it.

Before rebuilding components I mapped the underlying tokens: color, spacing, typography, and the relationships between them that power light/dark switching.

I rebuilt the basics first: buttons, links, and inputs. For each one, I worked through every property, variation, and theme combination (light and dark). The lever that made it scale was Figma local variables — wiring component properties to variables meant a single change at the token layer cascaded through every state and theme, instead of needing to be re-applied to each variant by hand.

All primary, secondary, and invisible button variants recreated with semantic controls for icon toggles and modes.

Built adaptive text inputs with full state coverage (rest, hover, disabled, error) and token-based layout.

Captured usage across interactions and modes, and tokenized typography and color handling for scale.

Working up from the atoms, I built molecular components — icon buttons, nav items — that combine multiple atoms with their own behavioral logic. The toggles for these live in Figma's right-hand panel, so a designer can switch a state without digging into the component itself.

To go beyond surface-level components, I rebuilt GitHub's tables — probably the most complex UI in the product. Labels, icons, and status tags became repeatable patterns inside a single table component, with style tokens cascading from the top so the same table works across many different contexts without forking it.

To check that the system actually held together, I rebuilt a full section of GitHub's UI using only the components I'd made. That's the test that catches the gaps — what nests inside what, how layout flexes, where assumptions break down. It's also where the value of a real system shows up: less time on layout, more on the parts that matter.

This wasn't just a practice exercise. Pulling a production-grade system apart and putting it back together changed how I think about systems work — sharper instincts on token structure, more confidence in Figma variables, and a clearer sense of what holds up when a design system has to survive real use.