diff --git a/src/storage/dao.ts b/src/storage/dao.ts
index 2ed586c..d544bf7 100644
--- a/src/storage/dao.ts
+++ b/src/storage/dao.ts
@@ -62,6 +62,47 @@ export function recordPR(ctx: PRContext, extras: { state?: string; closedAt?: st
   }
 }
 
+/**
+ * Record a PR close/merge from the webhook `pull_request.closed` event.
+ *
+ * This is the ONLY live path that persists `prs.merged_at`. The review path
+ * calls `recordPR(ctx, { state: "open" })` with no `mergedAt`, and that upsert
+ * always writes `merged_at = excluded.merged_at` (i.e. NULL), so a merge is
+ * never captured during review. A merge emits no further `synchronize` events,
+ * so setting `merged_at` here on close persists — which is what the Impact /
+ * Overview "caught before merge" and "merged PRs" metrics (they filter on
+ * `merged_at IS NOT NULL`) and cross-PR memory depend on.
+ *
+ * UPDATE-only by design: those metrics JOIN reviews → prs, so any PR that
+ * matters here already has a row from `recordPR` during its review. A PR the
+ * bot never reviewed no-ops harmlessly (it carries no findings anyway).
+ */
+export function markPRClosed(
+  owner: string,
+  repo: string,
+  number: number,
+  info: { merged: boolean; mergedAt?: string | null; closedAt?: string | null },
+): void {
+  const db = openDatabase();
+  if (!db) return;
+  try {
+    db.prepare(
+      `UPDATE prs
+         SET state = ?, closed_at = ?, merged_at = ?
+       WHERE owner = ? AND repo = ? AND number = ?`,
+    ).run(
+      info.merged ? "merged" : "closed",
+      info.closedAt ?? null,
+      info.merged ? info.mergedAt ?? null : null,
+      owner,
+      repo,
+      number,
+    );
+  } catch (err) {
+    logger.debug({ err }, "dao.markPRClosed failed");
+  }
+}
+
 /** Insert a review row, return its rowid. Returns null when persistence is disabled. */
 export function recordReview(opts: {
   ctx: PRContext;
diff --git a/src/webhook/dispatch.ts b/src/webhook/dispatch.ts
index ef89f85..5a9c57e 100644
--- a/src/webhook/dispatch.ts
+++ b/src/webhook/dispatch.ts
@@ -1,5 +1,5 @@
 import { logger } from "../logger.js";
-import { recordEvent } from "../storage/dao.js";
+import { markPRClosed, recordEvent } from "../storage/dao.js";
 import { bus } from "../realtime/bus.js";
 import { runReviewJob } from "../realtime/jobs.js";
 import { isPauseAll, isAutoReviewEnabled } from "../settings/overrides.js";
@@ -187,9 +187,18 @@ export async function dispatchWebhookEvent(
       return { status: 202, body: { status: "accepted" } };
     }
 
-    // closed — abort in-flight reviews
+    // closed — record the close/merge, then abort in-flight reviews
     if (action === "closed") {
-      logger.info({ owner, repo, pr: number, action }, "PR closed, aborting any in-flight review");
+      // Persist merge/close status. This is the only live path that sets
+      // prs.merged_at, which the Impact/Overview "caught before merge" and
+      // "merged PRs" metrics (and cross-PR memory) are gated on.
+      const pr = payload.pull_request;
+      const merged = !!pr.merged;
+      markPRClosed(owner, repo, number, { merged, mergedAt: pr.merged_at, closedAt: pr.closed_at });
+      logger.info(
+        { owner, repo, pr: number, action, merged },
+        merged ? "PR merged, recording merge and aborting any in-flight review" : "PR closed, aborting any in-flight review",
+      );
       reviewer.handlePRClose(owner, repo, number);
       return { status: 200, body: { status: "ok" } };
     }
diff --git a/web/src/styles/base.css b/web/src/styles/base.css
index 8930ece..062ad4c 100644
--- a/web/src/styles/base.css
+++ b/web/src/styles/base.css
@@ -1169,8 +1169,15 @@ label.field {
   display: flex;
   align-items: flex-end;
   gap: 3px;
-  flex: 1;
-  min-height: 140px;
+  /* `height` (not just min-height) so the bar has a *definite* height in any
+     layout context: percentage-based column/segment heights only resolve
+     against a definite ancestor. `flex: 1 1 auto` still lets the bar grow to
+     fill a taller stretched card (e.g. the Overview grid), but the explicit
+     height is the definite fallback when the card body is content-sized (e.g.
+     the standalone Impact "Findings by severity over time" card), which
+     otherwise collapsed every column to 0. */
+  flex: 1 1 auto;
+  height: 200px;
   padding: 6px 0;
 }
 .chart-bar .col {