diff --git a/BACKLOG.md b/BACKLOG.md
index 70c9e2c..600a877 100644
--- a/BACKLOG.md
+++ b/BACKLOG.md
@@ -15,15 +15,6 @@ In dark mode the "Clear" button text lightens on hover, giving visual feedback.
 mode and Dan mode it currently does nothing visible. Should have a matching subtle
 highlight (e.g. text darkens, underline appears, or border darkens).
 
-### Admin: allow renaming unit and group IDs
-The edit forms do not currently expose the `id` field for existing units or groups.
-
-- **Units:** straightforward — update `units[].id` and save.
-- **Groups:** update `groups[].id` and rewrite every `units[].group` reference in the
-  same atomic `saveData()` call.
-
-Validate that the new ID is unique and kebab-safe before committing in both cases.
-
 ### Admin: tooltips / descriptions for units
 Allow users to attach an optional `description` string to each unit. On the front end,
 show it as a tooltip when hovering over the unit name or symbol. A single `description`
diff --git a/src/lib/config.ts b/src/lib/config.ts
index b4c43c6..fd6f88c 100644
--- a/src/lib/config.ts
+++ b/src/lib/config.ts
@@ -11,12 +11,12 @@ export const FRACTIONAL_DIGITS: number = 8;
 
 /**
  * Output grid layout configuration.
- * Grid uses CSS Grid repeat(auto-fill, minmax(MIN_COLUMN_WIDTH, 1fr)).
- * Column count is automatic — determined by available width ÷ (MIN_COLUMN_WIDTH + GRID_GAP).
+ * Grid uses CSS media-query breakpoints for responsive column counts:
+ *   <480px  → 1 column
+ *   480–899px → 2 columns
+ *   ≥900px  → 3 columns
+ * See app.css .results-grid for the actual CSS.
  */
 
-/** Minimum tile width for the output grid. Controls automatic column count. */
-export const MIN_COLUMN_WIDTH: string = '160px';
-
 /** Gap between output grid tiles. Used for both row and column gaps. */
 export const GRID_GAP: string = '1rem';