diff --git a/CLAUDE.md b/CLAUDE.md
index 7a3c670..46cf9fc 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -3502,7 +3502,10 @@ would notice on 113 — the rule simply does not exist, there and nowhere
 else, which is how the bottom bar's `text-overflow: ellipsis` came to
 have never truncated on the device. `make css-check`
 (`frontend/scripts/check-css-nesting.mjs`, a pre-commit hook and a CI
-step) fails on one, over `index.css` and the `css` literals alike, and
+step) fails on one, over every `frontend/*.css` and the `css` literals
+alike — a glob rather than `index.css` by name, because the hook fires
+on `frontend/**/*.{ts,css}` and a sweep that names one file goes green
+over a stylesheet it never opened — and
 says the fix is a leading `&` — valid in both syntaxes, so no nested
 rule here has a reason to omit it. Two things it has to get right, and
 both follow from asking whether a *style* rule is anywhere above rather
diff --git a/frontend/scripts/check-css-nesting.mjs b/frontend/scripts/check-css-nesting.mjs
index 45daa76..6338793 100644
--- a/frontend/scripts/check-css-nesting.mjs
+++ b/frontend/scripts/check-css-nesting.mjs
@@ -18,10 +18,24 @@ import { findBareNestedRules } from './css-nesting.mjs';
 
 const problems = [];
 
-for (const { line, selector } of findBareNestedRules(
-  readFileSync('index.css', 'utf8'),
-)) {
-  problems.push({ file: 'index.css', line, selector });
+// Every stylesheet, not `index.css` by name: the hook that runs this
+// fires on `frontend/**/*.{ts,css}`, so naming one file promises a
+// coverage the sweep does not deliver -- a second stylesheet would be
+// silently unswept while the hook still went green over it. There is
+// only `index.css` today, which is exactly when this is free to fix.
+const stylesheets = globSync('*.css', { cwd: process.cwd() });
+
+if (stylesheets.length === 0) {
+  console.error('css-nesting-check: no stylesheet matched *.css');
+  process.exit(1);
+}
+
+for (const file of stylesheets) {
+  for (const { line, selector } of findBareNestedRules(
+    readFileSync(file, 'utf8'),
+  )) {
+    problems.push({ file, line, selector });
+  }
 }
 
 const sources = globSync('src/**/*.ts', { cwd: process.cwd() });
@@ -61,5 +75,5 @@ if (problems.length > 0) {
 }
 
 console.log(
-  `css-nesting-check: index.css + ${sources.length} files, no bare nested rules`,
+  `css-nesting-check: ${stylesheets.length} stylesheet(s) + ${sources.length} files, no bare nested rules`,
 );