allowlist: permit CSS hex color literals

Author: vekexasia

.pii-allowlist

@@ -1,6 +1,10 @@
 # Narrow allowlist for git-shield false positives in this repo.
 # One regex per line. See https://github.com/vekexasia/git-shield#allowlist
 
+# ── CSS hex color literals ──
+# 6-digit hex color values in palette definitions and test fixtures.
+#[0-9a-fA-F]{6}
+
 # ── Public URLs that aren't PII ──
 ^https?://(www\.)?keepachangelog\.com(/.*)?$
 ^https?://(www\.)?nextjs\.org(/.*)?$