fix(design): the S3g conformance sweep — primitives at their rung (E28 S3g)

The probe re-run over the 15 pages at 1920x1080 found every button, icon
button, chip, field, tab, segment and menu row drawn by its primitive
except the S3h Plex picture, a div with the button role. It is a
Pressable now, and the button-primitive lint rule refuses an element
with role="button" outside the control primitives.

- SegmentedToggle defaults to the toolbar rung (28, text-xs): the old
  small default had put the pager's page sizes and the YouTube result
  count on 10px type beside 28px buttons. The Plex match toggle asks
  for the small rung explicitly.
- The language badge on the rail uses text-3xs (was an 8px one-off);
  the Plex playlist's watched mark and the Home hero's length use
  MEDIA_BADGE instead of hand-copied classes.
- A media picture shows the pointer whether it is a link or a button.
- DESIGN.md: a Conformance chapter (the four-step check before a UI
  change is done, with the S3g baseline), the segmented rung, two log
  rows. CLAUDE.md points at the check.

CLAUDE.md

@@ -52,7 +52,7 @@ how it gets built. Concretely:
 - **Challenge unsound requests.** If a request is technically ill-advised and you can back it with real
   arguments, push back or propose an alternative — don't comply blindly.
 - **Verify UI in the browser before calling it done.** tsc/unit/DOM tests miss visual and interaction
-  bugs; do a real visual check of any UI change.
+  bugs; do a real visual check of any UI change, and run DESIGN.md's four-step Conformance check.
 - **Be terse everywhere else.** Outside those decision points, lead with the answer or decision. During
   implementation and debugging especially: no restating the same point reworded, no filler.
 

docs/DESIGN.md

@@ -18,6 +18,27 @@ owner settles it.
 - A rule stated here should also be enforced in code (an eslint rule, a primitive's type, a test). A rule
   that lives only in prose drifts. That is the finding that started this document.
 
+## Conformance — the check before a UI change is done
+
+A screen is measured against this document, not against taste. Every change that renders something new
+runs this check before it is called done (E28 S3g):
+
+1. **Primitives at a named rung.** Each control goes through its primitive (lint refuses the raw element,
+   and a `<div role="button">` with it), at a rung or role this document names: a `Button` size, an
+   `IconButton` size, a `Chip` size, the `SegmentedToggle` rung, a `SURFACE` role. The lint holds the
+   element, not the rung, so the rung is checked by eye and by measure.
+2. **The pattern's chapter, re-read.** The change matches the chapter of every pattern it touches, or it
+   opens a **Pending** item and a log row. It never quietly adds a second look.
+3. **Measured.** On the changed pages, the rendered elements are grouped by kind (button, icon button,
+   chip, field, tab, segment, menu row, surface) and by their computed look (radius, height, type, fill,
+   edge). Each distinct look maps to a rung or role named here; a look that maps to none is a violation
+   or a new decision. The S3g baseline across the 15 pages at 1920 × 1080: every button, icon button,
+   chip, field, tab, segment and menu row is drawn by its primitive. What the measure still counts as
+   hand-drawn is by design: text links (no primitive), surfaces painted by their `SURFACE` role (a class,
+   which the measure cannot trace to a component) and the playlist table's own rows.
+4. **Seen.** A screenshot of every changed state, thin edges at 1:1; the tablet widths (1024 × 768, a
+   narrow split screen) when the layout can reflow. Phones are the E29 epic's, not this check's.
+
 ## The design lab
 
 `npm run dev`, then open **`http://localhost:5173/design-lab`**. The lab renders each open decision's variants
@@ -189,7 +210,9 @@ Also in force:
 - **Unavailable with a reason** stays focusable: `aria-disabled` plus the reason in the label or tooltip,
   never native `disabled`, which drops it from the tab order with its explanation. [WCAG 2.1.1]
 - A choice between a few values is `SegmentedToggle`; a long list or a user's own list is `FilterSelect`.
-  Never a native `<select>` (lint-enforced).
+  Never a native `<select>` (lint-enforced). Its rung is the toolbar's, 28 with `text-xs`, so it lines up
+  with the triggers and the pager's buttons; the 24 rung with the smallest type is only a side panel's
+  captioned match toggle (S3g: the old small default had put a pager and a toolbar count on 10px type).
 - A single-select row of filter chips goes through `FilterChipGroup` (its options are `Chip`s).
 - A button that starts slow work shows `loading` (a spinner, `aria-busy`) and can't be pressed twice.
   [Nielsen #1]
@@ -564,3 +587,5 @@ pick a density step; it never changes the anatomy or loses an action. [Nielsen #
 | 2026-09-27 | C2 as built                                      | The side panel's drawer is `ui/Modal` `drawer-start`; drawer = a coarse pointer or below 768; the pin offered in its header ≥ 1024                                                                                                                                      | A drawer of its own inside `SidePanel`                                                                                                                                                                 | Esc, Back, the scrim, the trap and the scroll lock are the dialog's; a second implementation is how two shells drift                                                                          |
 | 2026-09-27 | Narrow rows by container                         | The download row, the playlist table and the Channels tag row stack by a container query; a fact line never wraps                                                                                                                                                       | Breakpoints on the window                                                                                                                                                                              | The iPad zoomed in, split screen and a column beside a rail are narrow while the window is not; the zoomed download row broke "18.9 / MB" apart                                               |
 | 2026-09-27 | Phones deferred                                  | A phone-only layout (the hamburger nav, a folded feed band) waits for its own epic; E28 stays desktop + tablet                                                                                                                                                          | Fix the phone views inside E28                                                                                                                                                                         | Principle 2; the first phone attempts made the feed worse, and the epic's review grows with every sprint                                                                                      |
+| 2026-09-27 | Conformance check (S3g)                          | A four-step check before a UI change is done: primitive at a named rung, the chapter re-read, the rendered page measured by kind and look, every state seen                                                                                                             | A reviewer's eye per sprint                                                                                                                                                                            | The S1 probe found 69 button looks; after S3 every control kind is drawn by its primitive, and the check keeps a new look from arriving unnoticed                                             |
+| 2026-09-27 | Segmented rung                                   | `SegmentedToggle` defaults to the toolbar rung (28, `text-xs`); 24 only for a panel's captioned match toggle                                                                                                                                                            | The small default                                                                                                                                                                                      | Two toolbars had inherited 10px type from the default beside 28px buttons                                                                                                                     |

frontend/eslint.config.js

@@ -109,6 +109,7 @@ const buttonPrimitive = {
     type: "problem",
     messages: {
       raw: "A raw <{{name}}> outside the control primitives: use ui/Button (a labelled action), IconButton (a glyph), Pressable (a card or row that is the control), Chip or DragHandle.",
+      role: 'A <{{name}} role="button"> is a hand-built button (its own Enter/Space, no focus-safe disabled, no touch target): use ui/Pressable for a surface that is the control.',
     },
   },
   create(context) {
@@ -121,6 +122,19 @@ const buttonPrimitive = {
         const name = node.name.name;
         if (name === "button" || name === "FocusSafeButton")
           context.report({ node, messageId: "raw", data: { name } });
+        // S3g: the same button spelled as a div with a role slipped past the rule above (my own
+        // S3h Plex picture). A component (capitalised) may take a role for its own reasons.
+        else if (
+          /^[a-z]/.test(name) &&
+          node.attributes.some(
+            (a) =>
+              a.type === "JSXAttribute" &&
+              a.name.name === "role" &&
+              a.value?.type === "Literal" &&
+              a.value.value === "button",
+          )
+        )
+          context.report({ node, messageId: "role", data: { name } });
       },
     };
   },

frontend/src/components/Feed.tsx

@@ -482,6 +482,7 @@ export default function Feed({
             <div className="ml-auto flex items-center gap-1.5 text-xs text-muted shrink-0">
               <span aria-hidden="true">{t("feed.yt.show")}</span>
               <SegmentedToggle
+                size="md"
                 ariaLabel={t("feed.yt.show")}
                 title={t("feed.yt.showHint")}
                 value={String(ytCount)}

frontend/src/components/Home.tsx

@@ -57,6 +57,7 @@ import { MediaResumeButtons } from "./MediaResumeButtons";
 import { MediaCard, MediaPlayGlyph } from "./ui/MediaCard";
 import {
   MEDIA_BAR,
+  MEDIA_BADGE,
   MEDIA_HOVER_LAYER,
   MEDIA_IMG,
   MEDIA_PICTURE,
@@ -559,7 +560,7 @@ function Hero({
       >
         <Pressable
           onClick={() => onPlay(card)}
-          className="relative block h-full w-full overflow-hidden rounded-lg border border-border bg-card"
+          className="relative block h-full w-full cursor-pointer overflow-hidden rounded-lg border border-border bg-card"
           aria-label={`${started ? t("home.hero.continue") : t("home.hero.play")}: ${card.title}`}
         >
           {card.thumb ? (
@@ -567,9 +568,7 @@ function Hero({
           ) : null}
           {card.duration_seconds != null && (
             // It steps aside while the hover row covers its corner, as a card's length does.
-            <span
+            <span className={`${MEDIA_BADGE} bottom-1.5 right-1.5 ${HOVER_YIELD}`}>
-              className={`absolute bottom-1.5 right-1.5 rounded-sm bg-black/80 px-1.5 py-0.5 text-2xs font-medium text-white tabular-nums ${HOVER_YIELD}`}
-            >
               {formatDuration(card.duration_seconds)}
             </span>
           )}

frontend/src/components/LanguageSwitcher.tsx

@@ -60,10 +60,12 @@ export default function LanguageSwitcher({
       >
         {rail ? (
           /* A rail row (F32), with the current-language badge (HU/EN) on the glyph's corner so the
-             active language reads at a glance. The ring matches the page to detach it from the icon. */
+             active language reads at a glance. The ring matches the page to detach it from the icon;
+             its type is the rail count badge's (text-3xs), the smallest step on the scale (it was an
+             8px one-off). */
           <span className="relative">
             <Globe className={RAIL_GLYPH} />
-            <span className="absolute -bottom-1.5 -right-2.5 text-[0.5rem] font-bold leading-none px-1 py-px rounded-sm bg-accent text-accent-fg ring-2 ring-bg">
+            <span className="absolute -bottom-1.5 -right-2.5 text-3xs font-bold leading-none px-1 py-px rounded-sm bg-accent text-accent-fg ring-2 ring-bg">
               {current.code.toUpperCase()}
             </span>
           </span>

frontend/src/components/PlexPlaylistView.tsx

@@ -53,6 +53,7 @@ import { Input } from "./ui/Input";
 import { useReturnFocus } from "./ui/useReturnFocus";
 import { SURFACE } from "./ui/surfaces";
 import { PageHeading } from "./ui/Headings";
+import { MEDIA_BADGE } from "./ui/mediaCardStyles";
 
 // A playlist's items, grouped for readability: movies stay standalone, while a run of episodes from the
 // same show collapses into a season/show group so a whole series doesn't sprawl into an endless flat
@@ -199,11 +200,7 @@ function EpisodeRow({ ep, ctx, dense }: { ep: PlexCard; ctx: Ctx; dense: boolean
           className={`relative shrink-0 overflow-hidden rounded-sm border border-border bg-surface ${dense ? "aspect-video w-14" : "aspect-video w-20"}`}
         >
           <img src={ep.thumb} alt="" loading="lazy" className="h-full w-full object-cover" />
-          {ep.status === "watched" && (
+          {ep.status === "watched" && <span className={`${MEDIA_BADGE} right-0.5 top-0.5`}>✓</span>}
-            <span className="absolute right-0.5 top-0.5 rounded-sm bg-black/70 px-1 text-[0.5625rem] text-white">
-              ✓
-            </span>
-          )}
           {inProgress && <div className="absolute inset-x-0 bottom-0 h-0.5 bg-accent" />}
           <div className="absolute inset-0 grid place-items-center bg-black/40 opacity-0 transition group-hover/thumb:opacity-100">
             <Play className="h-4 w-4 text-white" fill="currentColor" />

frontend/src/components/PlexSidebar.tsx

@@ -55,6 +55,7 @@ function MatchToggle({
   const { t } = useTranslation();
   return (
     <SegmentedToggle
+      size="sm"
       label={t("plex.filter.matchLabel")}
       ariaLabel={t("plex.filter.matchLabel")}
       options={[

frontend/src/components/plexCards.dom.test.tsx

@@ -270,7 +270,10 @@ describe("Plex cards in a keyboard-walkable list", () => {
     const root = container.firstElementChild as HTMLElement;
     expect(root.getAttribute("data-nav-index")).toBe("3");
     const open = root.querySelector<HTMLElement>("[data-nav-open]")!;
-    expect(open.getAttribute("role")).toBe("button");
+    // A real button (ui/Pressable), not a div wearing its role: Enter/Space and the touch target
+    // come from the primitive (S3g found the S3h picture hand-built).
+    expect(open.tagName).toBe("BUTTON");
+    expect(open.getAttribute("type")).toBe("button");
     fireEvent.click(open);
     expect(onOpen).toHaveBeenCalledTimes(1);
   });

frontend/src/components/plexCards.tsx

@@ -209,27 +209,14 @@ function PlexPicture({
   const started = plays && pct > 0 && !!onRestart;
   return (
     <div className={mediaPictureBox(aspect)}>
-      <div
+      <Pressable onClick={onOpen} aria-label={label} data-nav-open="" className={MEDIA_PICTURE}>
-        onClick={onOpen}
-        role="button"
-        tabIndex={0}
-        aria-label={label}
-        data-nav-open=""
-        onKeyDown={(e) => {
-          if (e.key === "Enter" || e.key === " ") {
-            e.preventDefault();
-            onOpen();
-          }
-        }}
-        className={clsx(MEDIA_PICTURE, "cursor-pointer")}
-      >
         <img src={thumb} alt="" loading="lazy" decoding="async" className={MEDIA_IMG} />
         {children}
         <div className={MEDIA_HOVER_LAYER}>
           {plays && !started && <MediaPlayGlyph small={small} />}
         </div>
         <MediaProgress pct={pct} />
-      </div>
+      </Pressable>
       {started && (
         <div
           className={clsx(

frontend/src/components/ui/Pager.tsx

@@ -113,6 +113,7 @@ export default function Pager({
           </span>
           {/* A handful of fixed sizes plus "All": segmented, the house control for a short fixed set. */}
           <SegmentedToggle
+            size="md"
             ariaLabel={sizeLabel}
             value={String(size)}
             onChange={(v) => {

frontend/src/components/ui/SegmentedToggle.dom.test.tsx

@@ -32,6 +32,17 @@ describe("SegmentedToggle", () => {
     expect(onChange).toHaveBeenCalledWith("and");
   });
 
+  it("sits on the toolbar rung unless a panel's caption asks for the small one (S3g)", () => {
+    render(<SegmentedToggle options={OPTS} value="or" onChange={vi.fn()} ariaLabel="Default" />);
+    const plain = screen.getByRole("group", { name: "Default" });
+    expect(plain.className).toContain("text-xs");
+    expect(plain.querySelector("button")!.className).toContain("h-7");
+    render(
+      <SegmentedToggle options={OPTS} value="or" onChange={vi.fn()} ariaLabel="Small" size="sm" />,
+    );
+    expect(screen.getByRole("group", { name: "Small" }).className).toContain("text-3xs");
+  });
+
   it("exposes the group aria-label", () => {
     render(<SegmentedToggle options={OPTS} value="or" onChange={vi.fn()} ariaLabel="Match mode" />);
     expect(screen.getByRole("group", { name: "Match mode" })).toBeTruthy();

frontend/src/components/ui/SegmentedToggle.tsx

@@ -21,7 +21,7 @@ export default function SegmentedToggle<T extends string>({
   label,
   title,
   fullWidth = false,
-  size = "sm",
+  size = "md",
   className,
 }: {
   options: readonly SegmentedOption<T>[];
@@ -37,7 +37,9 @@ export default function SegmentedToggle<T extends string>({
   title?: string;
   // Full-width track with flex-1 buttons (the scope bar); default is intrinsic width.
   fullWidth?: boolean;
-  // sm = text-3xs, compact padding (the captioned match toggles); md = text-xs (the scope bar).
+  // md (28, text-xs) is the toolbar rung: it lines up with the search pill, the triggers and an `sm`
+  // Button (DESIGN B1). sm (24, text-3xs) is only a side panel's captioned match toggle. md is the
+  // default because the old sm default slid a pager and a toolbar count onto 10px type (S3g).
   size?: "sm" | "md";
   className?: string;
 }) {

frontend/src/components/ui/mediaCardStyles.ts

@@ -4,9 +4,11 @@ import { HOVER_REVEAL } from "./reveal";
 // The one media card's classes (ui/MediaCard): the pieces a caller builds its picture from, kept in
 // a module of their own so the component file exports only components (fast refresh).
 
-/** The picture's own box: rounded inside the frame, edged, lifting its shadow on hover. */
+/** The picture's own box: rounded inside the frame, edged, lifting its shadow on hover. It is always
+ *  the card's open control, so it shows the hand whether it is a link (a video) or a button (a Plex
+ *  title, a shelf tile), which a button would not by itself. */
 export const MEDIA_PICTURE =
-  "relative block h-full w-full overflow-hidden rounded-xl border border-border bg-surface shadow-md transition-shadow group-hover:shadow-2xl";
+  "relative block h-full w-full cursor-pointer overflow-hidden rounded-xl border border-border bg-surface shadow-md transition-shadow group-hover:shadow-2xl";
 
 /** The picture's image: covers the box and zooms a little on hover. */
 export const MEDIA_IMG =

frontend/src/components/ui/pressableSelectable.contract.test.ts

@@ -32,6 +32,7 @@ const PLAIN: Record<string, [number, string]> = {
   "PlexPlaylistAdd.tsx": [1, "a checkbox row in a picker"],
   "PlexPlaylistView.tsx": [1, "a show's poster stack (aria-hidden)"],
   "PlexSearchBox.tsx": [1, "a listbox option"],
+  "plexCards.tsx": [1, "a card's picture (named by aria-label; its title is the caption)"],
   "Scheduler.tsx": [1, "the interval editor trigger"],
   "SettingsPanel.tsx": [1, "a colour swatch"],
   "SyncStatus.tsx": [1, "the status pill trigger"],

frontend/src/lib/buttonPrimitive.contract.test.ts

@@ -42,4 +42,15 @@ describe("a hand-rolled button", () => {
       ),
     ).toBe(0);
   });
+
+  it("is refused spelled as an element with the button role; a component's role is its own", async () => {
+    expect(await hits('export const F = () => <div role="button" tabIndex={0}>x</div>;\n')).toBe(1);
+    expect(await hits('export const G = () => <span role="button">x</span>;\n')).toBe(1);
+    expect(await hits('export const H = () => <div role="group">x</div>;\n')).toBe(0);
+    expect(
+      await hits(
+        'import { Pressable } from "./ui/Pressable";\nexport const I = () => <Pressable role="button">x</Pressable>;\n',
+      ),
+    ).toBe(0);
+  });
 });