fix(ci): keep index.css and useAtlas.ts within their size baselines

The opening pan now measures the north edge through a function chromePan
calls only where there is chrome to clear, so useAtlas needs no branch of
its own. index.css loses the long note on the dark field rule to one line,
and a .dark .bg-slate-100 rule that two later rules always overrode.

client/src/index.css

@@ -1290,7 +1290,6 @@ img[alt="TREK"] {
 
 /* ── Dark-Mode: Tailwind-Klassen ─────────────── */
 .dark .bg-slate-50 { background-color: #131316 !important; }
-.dark .bg-slate-100 { background-color: #1c1c21 !important; }
 .dark .bg-white { background-color: #09090b !important; }
 .dark .bg-gray-50 { background-color: #131316 !important; }
 .dark .bg-gray-100 { background-color: #1c1c21 !important; }
@@ -1307,10 +1306,7 @@ img[alt="TREK"] {
 .dark .bg-slate-100 { background-color: #27272a !important; }
 .dark .bg-slate-900 { background-color: #e4e4e7 !important; color: #09090b !important; }
 .dark .hover\:bg-slate-700:hover { background-color: #d4d4d8 !important; color: #09090b !important; }
-/* Not inside the touch shell (.m-root): its fields state their own fill, a
-   transparent input inside a rounded wrapper above all, and this rule outweighs
-   every utility class, so it painted a dark box inside each of them. The
-   :where() keeps the desktop's weight exactly as it was. */
+/* Not in the touch shell (.m-root), whose fields set their own fill; :where() keeps the desktop's weight. */
 .dark input:not(:where(.m-root *)), .dark textarea:not(:where(.m-root *)), .dark select:not(:where(.m-root *)) {
   background-color: #1c1c21;
   color: #f4f4f5;

client/src/pages/atlas/atlasChrome.test.ts

@@ -1,4 +1,4 @@
-import { describe, expect, it } from 'vitest';
+import { describe, expect, it, vi } from 'vitest';
 import { chromeFitPadding, chromePan } from './atlasChrome';
 
 // FE-ATLAS-CHROME-001 onwards: the atlas camera beside the touch shell's rail and header.
@@ -11,6 +11,14 @@ describe('atlas chrome insets', () => {
     expect(chromePan({ top: 62, start: 0 }, 83, false)).toBeNull();
   });
 
+  it('FE-ATLAS-CHROME-005: the north edge is measured only where there is chrome to clear', () => {
+    const measure = vi.fn(() => -77);
+    expect(chromePan(undefined, measure, false)).toBeNull();
+    expect(measure).not.toHaveBeenCalled();
+    expect(chromePan({ top: 62, start: 0 }, measure, false)).toEqual([0, -139]);
+    expect(measure).toHaveBeenCalledTimes(1);
+  });
+
   it('FE-ATLAS-CHROME-002: the world moves away from the rail, in either reading direction', () => {
     expect(chromePan({ top: 62, start: 100 }, 83, false)).toEqual([-50, 0]);
     expect(chromePan({ top: 62, start: 100 }, 83, true)).toEqual([50, 0]);

client/src/pages/atlas/atlasChrome.ts

@@ -23,16 +23,17 @@ export const NORTH_EDGE_LAT = 75;
  * inhabited top (NORTH_EDGE_LAT, at `northEdgeY` in the map's own pixels) needs
  * to clear the header: a tall window shows it below the header anyway, a phone
  * had the stars of the far north under it. Leaflet pans the camera, so the
- * numbers point the other way from the world's move.
+ * numbers point the other way from the world's move. `northEdgeY` may be a
+ * measurement, taken only where there is chrome: the desktop atlas has none.
  */
 export function chromePan(
   insets: AtlasChromeInsets | undefined,
-  northEdgeY: number,
+  northEdgeY: number | (() => number),
   rtl = documentRtl()
 ): [number, number] | null {
   if (!insets) return null;
   const x = insets.start ? (rtl ? 1 : -1) * (insets.start / 2) : 0;
-  const y = Math.min(0, northEdgeY - insets.top);
+  const y = Math.min(0, (typeof northEdgeY === 'function' ? northEdgeY() : northEdgeY) - insets.top);
   return x || y ? [x, y] : null;
 }
 

client/src/pages/atlas/useAtlas.ts

@@ -373,10 +373,8 @@ export function useAtlas(options: { chromeInsets?: () => AtlasChromeInsets } = {
     map.getPane('regionPane')!.style.zIndex = '401'
 
     mapInstance.current = map
-    // The opening view centres the world beside the screen's chrome, not behind the rail and under the header.
-    // Measured only where there is chrome to clear: the desktop atlas opens exactly as before.
-    const insets = chromeInsetsRef.current?.()
-    const pan = insets ? chromePan(insets, map.latLngToContainerPoint([NORTH_EDGE_LAT, 0]).y) : null
+    // The opening view clears the touch shell's rail and header; the desktop atlas has none and opens as before.
+    const pan = chromePan(chromeInsetsRef.current?.(), () => map.latLngToContainerPoint([NORTH_EDGE_LAT, 0]).y)
     if (pan) map.panBy(pan, { animate: false })
     // Both renderers live as long as the map does (see the note on the refs); map.remove()
     // disposes them along with every other layer it holds.