Injected on every turn while mounted. Shown verbatim — a pack's rules are public by design.
Block theme, not classic: `style.css` (header comment), `theme.json`, `templates/index.html`. No `index.php`, `header.php`, `footer.php`, `wp_head()`, or hand-written loop. Missing `templates/index.html` makes it a classic theme silently, with no site editor.
style.css opens with a valid header: `Theme Name` minimum, plus Version, Requires at least, Requires PHP, License, Text Domain — inside the first 8 KB.
Declare presets, then APPLY them under styles: The defect that makes a correct theme look unstyled. `settings` says what is *available*; `styles` says what is *used*. `fontFamilies` without `styles.typography.fontFamily` renders in Times New Roman and reports no error. Minimum `styles`: typography fontFamily, fontSize, lineHeight; color background and text; `elements.link` colour; `spacing.blockGap`.
line-height is set explicitly: Unset computes to `normal` (~1.2), too tight for body copy. Root 1.5–1.7; display 1.05–1.2 via `styles.elements.h1`/`h2`.
One type ratio, whole scale fluid: Five to seven steps from a single ratio (1.2, 1.25, 1.333), never arbitrary values. `settings.typography.fluid: true` so every step gets a clamp. Display travels between viewports; body copy barely moves.
contentSize is a measure, and content is actually constrained: Target 45–75 characters per line — about 34–42rem, not 1200px. It only applies inside a group with `{"layout":{"type":"constrained"}}`, so templates wrap their content in one. `wideSize` for media and section furniture.
Colour is chosen, not defaulted to the extremes: Near-black on off-white, never `#000` on `#fff` — 21:1 is glare. Four roles named by role, not hue: base, contrast, primary, secondary, so a style variation can swap the theme by redefining four values. AA (4.5:1 body, 3:1 large) is the floor, not the target.
CSS reads presets through their custom properties: `var(--wp--preset--color--primary)`, `var(--wp--preset--spacing--50)`, `var(--wp--preset--font-size--large)` — never a repeated hex or rem. `settings.custom` tokens read as `var(--wp--custom--…)` with camelCase keys kebab-cased.
Spacing comes from the scale; blockGap is set once: Section padding uses `var(--wp--preset--spacing--N)`, never a fixed rem. `styles.spacing.blockGap` set at the root is worth more than any per-block margin.
Sections carry rhythm: Alternate full-bleed bands (`{"align":"full"}` with a background), a constrained reading column, and wide media. Identical spacing throughout reads as a list, not a design.
Interactive elements get hover and focus: Every link and button declares `:hover` and `:focus-visible`. Hover colours come from `color-mix()` against a preset so they track the palette. Never `outline: none` without a visible replacement.
Optical corrections are applied: `letter-spacing: -0.02em` and `text-wrap: balance` on display headings, `text-wrap: pretty` on body copy, about `0.08em` positive tracking on all-caps labels.
Header and footer contain real content: Header: site title or logo plus navigation in a `flex` group with `justifyContent: space-between`. Footer: site title, tagline or copyright, usually navigation. An empty part reads as broken, not simple.
Never put PHP in a template or part: `templates/*.html` and `parts/*.html` are not executed. PHP in them is emitted as literal text, which leaves an attribute unterminated and swallows the rest of the document — a catastrophically broken page with no PHP error and a 200 response. Dynamic values come from blocks (`wp:site-title`, `wp:site-tagline`, `wp:navigation`). Only `patterns/*.php` are PHP.
Block markup uses correct delimiters: `<!-- wp:group -->`…`<!-- /wp:group -->` with content, `<!-- wp:post-title /-->` self-closing, valid JSON attributes. Template parts referenced as `<!-- wp:template-part {"slug":"header","tagName":"header"} /-->` with the file present in `parts/` and an entry in `templateParts`.
Layout type is chosen deliberately: `constrained` for content, `default` for full-bleed wrappers, `flex` with `justifyContent` for rows, `grid` with `minimumColumnWidth` for cards. Never a hand-rolled `max-width` container.
Root padding uses root-padding-aware alignments: When the root has horizontal padding, `useRootPaddingAwareAlignments` is true and the padding is declared in `styles.spacing.padding`, so `.alignfull` reaches the edges.
functions.php stays minimal, and never duplicates theme.json: At most: enqueue `get_stylesheet_uri()` versioned by `wp_get_theme()->get('Version')`, `wp-block-styles`, `custom-logo`, `add_editor_style()`. No `editor-color-palette`, no `editor-font-sizes`, no `$content_width`, no `register_nav_menus`.
Modern CSS, and no !important against core: `clamp()` preferred terms include a `rem` component — never viewport units alone, which breaks zoom. `repeat(auto-fit, minmax(min(Xrem, 100%), 1fr))` and container queries over viewport breakpoints. Logical properties (`margin-inline`, `padding-block`) so RTL needs no second stylesheet. Global styles are wrapped in `:root :where(...)` and carry near-zero specificity, so a plain class already wins.
Accessibility is built in, not added later: Visible focus rings, a `prefers-reduced-motion` block, meaningful `alt`, a skip-link anchor on the main region, tap targets ≥ 24px.
Strings are translated; output is escaped: `__()` / `esc_html__()` with a literal text domain matching the header. `esc_html()`, `esc_attr()`, `esc_url()` on anything dynamic a PHP pattern or template prints.
Patterns and child themes follow their conventions: Patterns: files in `patterns/` with `Title` and a namespaced `Slug`, no `register_block_pattern()`. Child themes: `Template:` is the parent's directory name exactly, and theme.json merges rather than replaces.
Ship screenshot.png and readme.txt: 1200×900 screenshot, or the Appearance screen shows a grey placeholder. Readme carries licence attributions. Fonts are bundled locally and GPL-compatible, never fetched from a CDN.
YantrikDB