fix(map): the hero map's fade to the header was hardcoded white

The fade between the map band and the school header ramped through
rgba(255,255,255,...) and landed on var(--bg-card). In the light theme
that is white into white and invisible, as designed. In the dark theme
it climbed to 95% WHITE and then met a near-black card, putting a bright
band across the full width exactly where the map should dissolve into
the title.

Fading to the colour the gradient lands on is the whole trick, and it
only works if that colour is a token — so --bg-card-rgb now exists in
both theme blocks, matching the --hero-ground-rgb precedent.

Two more defects in the same file, same cause, found while in there:

The controls floating over the map paired a hardcoded white background
with color: var(--text-primary), which resolves to #E9EEF0 in dark —
near-white text on a near-white button. These deliberately do NOT follow
the theme, because the map tiles are light in both, so the ink is now
literal too and says why. A themed token is the wrong tool for a surface
that never changes.

The loading skeleton swept 50% white across var(--bg-secondary), which
is a bright flash every 1.4s on a dark page. It now sweeps toward the
card colour, a shade lighter than the ground in both themes.

The guard is a stylesheet test rather than a render test, because the
bug is invisible in the theme it was written for. Verified by reverting
each fix in turn: it names .fade and .openHint exactly.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015mWQnpye9F299NVRCCSRvj

docs/DEPLOY.md

@@ -206,11 +206,30 @@ registry is orphaned and nothing reads it.
    variable, and set `UNLEASH_URL` to `http://<UNLEASH_IP>:4242/api`.
 5. Redeploy the application stacks.
 
+### Adding a flag to Unleash
+
+**Unleash does not create flags by itself.** The SDK reads definitions from the
+server and never registers anything, and metrics for a flag the server has
+never heard of are discarded. So a flag declared in `backend/flags.py` will be
+evaluated on every request, stay `False` forever, and never appear in the UI
+until someone creates it there by hand.
+
+For each flag in the registry, create one in Unleash with:
+
+- **Name** — character for character what `backend/flags.py` declares.
+  snake_case, no hyphens or spaces. A typo produces a flag that looks correct
+  in the UI and is read by nothing.
+- **Type** — Release. No strategies, constraints or variants: these are plain
+  on/off switches, by design.
+
 ### Turning a feature on
 
-Toggle the flag in the environment you want. Flags appear in the Unleash UI
-after the backend has evaluated them once, so a newly declared flag shows up
-shortly after the deploy that introduced it.
+Toggle the flag in the environment matching the stack you mean: **development**
+for staging, **production** for prod. The token in each stack is scoped to one
+environment, so toggling the other one has no visible effect.
+
+The SDK refreshes every 15 seconds, so the API reflects the change almost at
+once; the pages follow on their own schedule, below.
 
 A flip reaches school pages within about five minutes and place pages within
 the hour. Next's ISR does the propagating — it revalidates a route at the

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

@@ -0,0 +1,78 @@
+import fs from 'fs';
+import path from 'path';
+
+/**
+ * Guards against light-theme-only CSS.
+ *
+ * The site themes entirely through tokens redefined under
+ * `@media (prefers-color-scheme: dark)`. A hardcoded colour therefore does not
+ * fail loudly — it renders perfectly in the theme it was written for and
+ * quietly wrongly in the other, which nobody sees unless they happen to be in
+ * dark mode when they look.
+ *
+ * Both rules below are drawn from real defects in SchoolHeroMap.module.css,
+ * found by eye rather than by any test:
+ *
+ *  - the map's fade to the header ramped through hardcoded white and landed on
+ *    `var(--bg-card)`. Invisible in light; a bright band across the full width
+ *    of a near-black card in dark.
+ *  - the controls floating over the map paired a hardcoded white background
+ *    with `color: var(--text-primary)`, which resolves to #E9EEF0 in dark —
+ *    near-white text on a near-white button.
+ */
+
+const COMPONENTS = path.join(__dirname, '..', '..', 'components');
+
+function stylesheets(dir: string): string[] {
+  return fs.readdirSync(dir, { withFileTypes: true }).flatMap((entry) => {
+    const full = path.join(dir, entry.name);
+    if (entry.isDirectory()) return stylesheets(full);
+    return entry.name.endsWith('.module.css') ? [full] : [];
+  });
+}
+
+/** Innermost `selector { body }` pairs. Nested at-rules never match as rules,
+ *  because their body contains braces. */
+function rules(css: string): Array<{ selector: string; body: string }> {
+  return Array.from(css.matchAll(/([^{}]+)\{([^{}]*)\}/g), (m) => ({
+    selector: m[1].trim().split('\n').pop()!.trim(),
+    body: m[2],
+  }));
+}
+
+const HARDCODED_WHITE_BG = /background[^;]*(?:255,\s*255,\s*255|#fff\b|#ffffff\b)/i;
+const THEMED_COLOR = /(?:^|[^-])color:\s*var\(--/;
+
+const files = stylesheets(COMPONENTS);
+
+describe('dark-theme safety', () => {
+  it('finds stylesheets to check', () => {
+    expect(files.length).toBeGreaterThan(0);
+  });
+
+  it('never pairs a hardcoded white background with a themed text colour', () => {
+    const offenders = files.flatMap((file) =>
+      rules(fs.readFileSync(file, 'utf8'))
+        .filter((r) => HARDCODED_WHITE_BG.test(r.body) && THEMED_COLOR.test(r.body))
+        .map((r) => `${path.relative(COMPONENTS, file)}  ${r.selector}`));
+
+    // Either the surface follows the theme and so should the text, or it does
+    // not and the text must be literal too. Mixing them is how near-white text
+    // ends up on a near-white button.
+    expect(offenders).toEqual([]);
+  });
+
+  it('never fades to a themed colour through a hardcoded one', () => {
+    const offenders = files.flatMap((file) =>
+      rules(fs.readFileSync(file, 'utf8'))
+        .filter((r) => /linear-gradient/.test(r.body)
+          && /var\(--bg-(card|primary|secondary)\)/.test(r.body)
+          && /255,\s*255,\s*255|#fff\b/i.test(r.body))
+        .map((r) => `${path.relative(COMPONENTS, file)}  ${r.selector}`));
+
+    // A gradient that lands on a token has to be made of that token, or the
+    // ramp and its destination disagree in one theme. Use the matching
+    // `--*-rgb` token for the transparent stops.
+    expect(offenders).toEqual([]);
+  });
+});

nextjs-app/app/globals.css

@@ -28,6 +28,9 @@
     --bg-primary: #FAFAF8;      /* Warm White */
     --bg-secondary: #F5EFE6;    /* Sand — hero panels, sunken rows */
     --bg-card: #FFFFFF;
+    /* For gradients that have to fade to the card colour. A hardcoded white
+       ramp reads as a bright band against a dark card. */
+    --bg-card-rgb: 255, 255, 255;
     --surface-inverse: #0F766E;
 
     /* ── Ink ────────────────────────────────────────────────────────── */
@@ -234,6 +237,7 @@
         --bg-primary: #111A20;
         --bg-secondary: #16222A;
         --bg-card: #18242C;
+        --bg-card-rgb: 24, 36, 44;
         --surface-inverse: #E9EEF0;
 
         --text-primary: #E9EEF0;

nextjs-app/components/SchoolHeroMap.module.css

@@ -47,7 +47,13 @@
     width: 100%;
     height: 100%;
     background:
-        linear-gradient(100deg, rgba(255, 255, 255, 0) 40%, rgba(255, 255, 255, .5) 50%, rgba(255, 255, 255, 0) 60%) var(--bg-secondary);
+        /* Sweeps toward the card colour, which is a shade lighter than this
+           ground in both themes. Hardcoded white was a bright flash across a
+           dark page every 1.4s while the tiles loaded. */
+        linear-gradient(100deg,
+            rgba(var(--bg-card-rgb), 0) 40%,
+            rgba(var(--bg-card-rgb), .5) 50%,
+            rgba(var(--bg-card-rgb), 0) 60%) var(--bg-secondary);
     background-size: 200% 100%;
     animation: shimmer 1.4s infinite;
 }
@@ -76,6 +82,15 @@
     justify-content: center;
 }
 
+/*
+ * Controls that float ON the map.
+ *
+ * The map tiles are light in both themes, so these deliberately do NOT follow
+ * the theme — they follow the map. The literal ink below is the point: paired
+ * with a hardcoded white background, `color: var(--text-primary)` resolved to
+ * #E9EEF0 in the dark theme and put near-white text on a near-white button.
+ * A themed token is the wrong tool for a surface that never changes.
+ */
 .openHint {
     display: inline-flex;
     align-items: center;
@@ -85,7 +100,8 @@
     border-radius: 999px;
     font-size: 13px;
     font-weight: 600;
-    color: var(--text-primary);
+    /* See "Controls that float ON the map" above. */
+    color: #1C2731;
     background: rgba(255, 255, 255, .85);
     -webkit-backdrop-filter: blur(6px);
     backdrop-filter: blur(6px);
@@ -113,11 +129,18 @@
        on top of the blend. */
     z-index: 450;
     pointer-events: none;
+    /* The card colour, not white.
+       This ramp was hardcoded white and ended at var(--bg-card). In the light
+       theme that is white into white and invisible, as intended. In the dark
+       theme it climbed to 95% WHITE and then met a near-black card — a bright
+       band across the full width, right where the map is supposed to dissolve
+       into the header. Fading to the same colour the gradient lands on is the
+       whole trick, and it only works if that colour is a token. */
     background: linear-gradient(to bottom,
-            rgba(255, 255, 255, 0) 0%,
-            rgba(255, 255, 255, .35) 35%,
-            rgba(255, 255, 255, .75) 62%,
-            rgba(255, 255, 255, .95) 82%,
+            rgba(var(--bg-card-rgb), 0) 0%,
+            rgba(var(--bg-card-rgb), .35) 35%,
+            rgba(var(--bg-card-rgb), .75) 62%,
+            rgba(var(--bg-card-rgb), .95) 82%,
             var(--bg-card) 100%);
 }
 
@@ -134,7 +157,8 @@
     border: none;
     border-radius: 8px;
     background: rgba(255, 255, 255, .92);
-    color: var(--text-primary);
+    /* See "Controls that float ON the map" above. */
+    color: #1C2731;
     cursor: pointer;
     box-shadow: 0 2px 10px rgba(var(--shadow-rgb), .2);
 }