fix(map): the popup never took the dark theme

leaflet.css paints `background: white; color: #333` on the popup card and its
tip. LeafletMapInner binds themed content into it — the school name and the
headline figure are var(--text-primary) — so in dark mode #E9EEF0 landed on
#FFFFFF at 1.17:1. The two things the popup exists to say were the two least
readable things on the page.

Every other foreground in that popup failed too, from the same cause: the
muted phase line at 2.90:1, the vs-national delta at 1.94:1, the Ofsted badge
at 1.74:1. Moving the surface onto --bg-card fixes all of them at once —
13.52, 5.45, 8.14 and 9.11:1 respectively. In light mode --bg-card is #FFFFFF,
so the popup renders exactly as it did.

globals.css already pulls the rest of Leaflet's chrome onto the tokens, and
says why: "this matters most in dark mode, where Leaflet's white attribution
bar would otherwise sit on a near-black page." The popup was simply missed.

The View Details button needed its own fix. It pairs background:var(--status-
above) with a literal white label, which theming the card does not reach:
--status-above is #36743F in light but #7FCB8A in dark, taking the label from
5.63:1 to 1.94:1. --text-inverse is the token for ink on a saturated fill, and
the popup's own Ofsted badge already uses it.

darkThemeSafety already guards this defect class, but only inside .module.css.
Neither half of this one lives there — the surface is a third party's, the
text is inline in a TSX template — so it scanned clean throughout. Two rules
added for the layer it could not see. Fixing the grouped-selector blind spot
in its rules() helper was needed to write them: taking only a selector's last
line discarded every selector in a grouped rule but the final one, which makes
a safety guard fail open.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FuPUioHpxtaiDNagQvjxyM

nextjs-app/__tests__/components/darkThemeSafety.test.ts

@@ -32,10 +32,17 @@ function stylesheets(dir: string): string[] {
 }
 
 /** Innermost `selector { body }` pairs. Nested at-rules never match as rules,
- *  because their body contains braces. */
+ *  because their body contains braces.
+ *
+ *  Comments are stripped before matching rather than after, so that the whole
+ *  selector survives. Taking only its last line — which is what stripping a
+ *  leading comment used to require — silently discarded every selector in a
+ *  grouped rule but the final one, and a safety guard that cannot see half its
+ *  input fails open. */
 function rules(css: string): Array<{ selector: string; body: string }> {
-  return Array.from(css.matchAll(/([^{}]+)\{([^{}]*)\}/g), (m) => ({
-    selector: m[1].trim().split('\n').pop()!.trim(),
+  const bare = css.replace(/\/\*[\s\S]*?\*\//g, '');
+  return Array.from(bare.matchAll(/([^{}]+)\{([^{}]*)\}/g), (m) => ({
+    selector: m[1].trim().replace(/\s*\n\s*/g, ' '),
     body: m[2],
   }));
 }
@@ -45,6 +52,15 @@ const THEMED_COLOR = /(?:^|[^-])color:\s*var\(--/;
 
 const files = stylesheets(COMPONENTS);
 
+/** Component sources, for the third-party-surface rule below. */
+function sources(dir: string): string[] {
+  return fs.readdirSync(dir, { withFileTypes: true }).flatMap((entry) => {
+    const full = path.join(dir, entry.name);
+    if (entry.isDirectory()) return sources(full);
+    return entry.name.endsWith('.tsx') ? [full] : [];
+  });
+}
+
 describe('dark-theme safety', () => {
   it('finds stylesheets to check', () => {
     expect(files.length).toBeGreaterThan(0);
@@ -76,3 +92,73 @@ describe('dark-theme safety', () => {
     expect(offenders).toEqual([]);
   });
 });
+
+/**
+ * The same defect one stylesheet further out.
+ *
+ * The rules above scan our own CSS modules. They cannot see a surface painted
+ * by a third-party sheet: leaflet.css hardcodes `background: white` on
+ * `.leaflet-popup-content-wrapper` and `.leaflet-popup-tip`, and
+ * LeafletMapInner builds its popup as an HTML string with inline
+ * `color: var(--text-primary)`. Neither half lives in a .module.css, so the
+ * module scan passed while dark mode rendered #E9EEF0 on #FFFFFF — 1.17:1,
+ * with the school name and the headline figure effectively invisible.
+ *
+ * globals.css already pulls the rest of Leaflet's chrome onto the tokens (the
+ * attribution bar, the zoom controls) for exactly this reason. The popup was
+ * simply missed.
+ */
+describe('third-party surfaces under themed text', () => {
+  const GLOBALS = path.join(__dirname, '..', '..', 'app', 'globals.css');
+
+  /** Leaflet surfaces our own code writes token-coloured text onto. */
+  const LEAFLET_POPUP_SURFACES = [
+    '.leaflet-popup-content-wrapper',
+    '.leaflet-popup-tip',
+  ];
+
+  it('still finds a component painting themed text into a Leaflet popup', () => {
+    // Guards the rule below against passing vacuously if the popups are ever
+    // rewritten as React components rather than HTML strings.
+    const themed = sources(COMPONENTS).filter((file) => {
+      const src = fs.readFileSync(file, 'utf8');
+      return /bindPopup\(/.test(src) && /color:var\(--|color: var\(--/.test(src);
+    });
+
+    expect(themed.length).toBeGreaterThan(0);
+  });
+
+  it('themes the Leaflet popup surface, because the text on it is themed', () => {
+    const globals = rules(fs.readFileSync(GLOBALS, 'utf8'));
+
+    const unthemed = LEAFLET_POPUP_SURFACES.filter((surface) => {
+      const rule = globals.find((r) => r.selector.includes(surface));
+      return !rule || !/background[^;]*var\(--/.test(rule.body);
+    });
+
+    // Leaflet's white is not a colour this site owns. Either the surface
+    // follows the theme or the text on it must be literal — and the text is
+    // already themed.
+    expect(unthemed).toEqual([]);
+  });
+
+  it('never puts a literal white label on a themed fill', () => {
+    /*
+     * The mirror image of the module-CSS rule above, and the half of the popup
+     * that theming the card does not reach. "View Details" is
+     * `background:var(--status-above);color:white`; --status-above is #36743F
+     * in light but #7FCB8A in dark, so the label went from 5.63:1 to 1.94:1.
+     *
+     * --text-inverse is the token for ink on a saturated fill — #FFFFFF in
+     * light, #111A20 in dark — and the popup's Ofsted badge already uses it.
+     */
+    const offenders = sources(COMPONENTS).flatMap((file) => {
+      const src = fs.readFileSync(file, 'utf8');
+      return Array.from(
+        src.matchAll(/background:\s*var\(--[^;"']*;[^"']*?color:\s*(white|#fff\b|#ffffff\b)/gi),
+        () => path.relative(COMPONENTS, file));
+    });
+
+    expect(offenders).toEqual([]);
+  });
+});

nextjs-app/app/globals.css

@@ -588,6 +588,35 @@ html .leaflet-bar a:hover {
     color: var(--text-primary);
 }
 
+/*
+ * The popup, which leaflet.css paints `background: white; color: #333` on both
+ * the card and its tip. The content LeafletMapInner binds into it is themed —
+ * the school name and the headline figure are `var(--text-primary)` — so in
+ * dark mode that was #E9EEF0 on #FFFFFF, a contrast ratio of 1.17:1. The name
+ * and the number were the two least readable things on the page.
+ *
+ * Moving the surface onto --bg-card fixes every foreground at once rather than
+ * one at a time: the muted phase line goes 2.90:1 -> 5.45:1, the vs-national
+ * delta 1.94:1 -> 8.14:1, the Ofsted badge 1.74:1 -> 9.11:1. In light mode
+ * --bg-card is #FFFFFF, so the popup looks as it always did.
+ */
+html .leaflet-popup-content-wrapper,
+html .leaflet-popup-tip {
+    background: var(--bg-card);
+    color: var(--text-primary);
+}
+
+/* Leaflet's own selector is `.leaflet-container a.leaflet-popup-close-button`
+   at 0,2,1 — an `html` prefix alone would lose to it. */
+html .leaflet-container a.leaflet-popup-close-button {
+    color: var(--text-muted);
+}
+
+html .leaflet-container a.leaflet-popup-close-button:hover,
+html .leaflet-container a.leaflet-popup-close-button:focus {
+    color: var(--text-primary);
+}
+
 /* Main content column */
 .main {
     max-width: 1400px;

nextjs-app/components/LeafletMapInner.tsx

@@ -184,7 +184,7 @@ export default function LeafletMapInner({ schools, center, zoom, referencePoint,
     ${phaseLabel}${school.local_authority ? ` · ${escapeHtml(school.local_authority)}` : ''}${distanceStr}
   </div>
   ${metricHtml}
-  <a href="${slug}" style="display:block;text-align:center;padding:6px;background:var(--status-above);color:white;border-radius:5px;text-decoration:none;font-size:12px;font-weight:600;margin-top:8px">View Details →</a>
+  <a href="${slug}" style="display:block;text-align:center;padding:6px;background:var(--status-above);color:var(--text-inverse);border-radius:5px;text-decoration:none;font-size:12px;font-weight:600;margin-top:8px">View Details →</a>
 </div>`;
 
         marker.bindPopup(popupContent);