# Developer guide > Implement the projectious.work design system with semantic tokens, documented patterns, and reproducible checks. ## Build from roles, not screenshots Start with semantic roles such as `--bg`, `--surface`, `--fg-1`, `--border`, `--tag-bg`, and the semantic status triples. Primitive scale steps support those roles. A screenshot is verification evidence, not a source file. ## Select the appearance explicitly ```html ``` Use `data-theme="dark"` for navy dark, the default dark appearance. Add `data-surface="deep"` for deep dark. Review all three because elevation, borders, and page/surface separation change even when typography and status roles do not. ## Use the three type roles ```css .heading { font-family: var(--font-heading); } .copy { font-family: var(--font-body); } .system-output { font-family: var(--font-code); } ``` Self-hosted builds must ship all specified weights. IBM Plex Mono needs 400, 500, 600, and 700 in upright and italic because syntax meaning is carried by weight and style as well as hue. ## Compose interfaces Use a 12-column desktop grid, 8 columns at medium widths, and 4 at the base. Two-column layouts begin at 768 px; persistent sidebars begin at 1024 px. Keep the reading measure at 65ch and every touch target at least 44 px. Solid accent controls use `--color-accent-solid` with `--fixed-control-text`. Semantic tints use their matching `-fg`. On dark surfaces, pair `--shadow-N` with `--elevated-N`; the surface step carries the visible elevation. ## Code and terminal surfaces Code is dark by default on `--code-panel-surface` (`#131e2b`). A terminal is deeper on `--terminal-surface` (`#0e1720`). A light code or terminal specimen is an explicit opt-in and must use the complete light companion set, including selection colours and chrome. ## Verify before release ```sh ./scripts/verify.sh ``` The verification contract includes generated-token parity, font and manifest integrity, Hugo output, AI discovery, MCP protocol behavior, contrast across appearances, and internal links. Add fit tests for any fixed-size card, slide, or export under loose text spacing and 200% text. --- Source: https://projectious-work.github.io/brand/docs/developer-guide/index.md