DRY pass #2, batch 8: the web's leftovers (#5372)

- notes/datetime.ts formatLocalDay had no caller; removed.
- style.css set body in two consecutive blocks; they are one.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/src/notes/datetime.ts

@@ -50,12 +50,6 @@ export function addLocalDays(d: Date, days: number): Date {
   return new Date(d.getFullYear(), d.getMonth(), d.getDate() + days);
 }
 
-// Format a local Date as "YYYY-MM-DD" (the shape an <input type="date"> reads).
-export function formatLocalDay(d: Date): string {
-  const pad = (n: number) => String(n).padStart(2, "0");
-  return `${d.getFullYear()}-${pad(d.getMonth() + 1)}-${pad(d.getDate())}`;
-}
-
 // --- Trash retention. The server permanently deletes a trashed note once it's older
 // than `trash_retention_days` (0 = keep forever). Counting down from the note's own
 // deleted_at is what turns that from a surprise into a policy: a card in Trash can