diff --git a/src/screens/RunReviewScreen.tsx b/src/screens/RunReviewScreen.tsx
index 6fba93a..35d3bd7 100644
--- a/src/screens/RunReviewScreen.tsx
+++ b/src/screens/RunReviewScreen.tsx
@@ -21,14 +21,36 @@ import { shortDate } from '../format';
  * the same thing; anchored before the August spike, a run can genuinely come
  * back "nothing to report" — which is what most mornings look like.
  */
+function ModeCard({ active, onClick, title, body }: { active: boolean; onClick: () => void; title: string; body: string }) {
+  return (
+    <button
+      type="button"
+      onClick={onClick}
+      aria-pressed={active}
+      className={`rounded-lg border px-3.5 py-3 text-left transition-colors ${
+        active ? 'border-brand bg-brand/10 ring-1 ring-brand ring-inset' : 'border-line hover:border-brand/60'
+      }`}
+    >
+      <span className="block text-sm font-semibold text-ink">{title}</span>
+      <span className="mt-1 block text-xs leading-relaxed text-muted">{body}</span>
+    </button>
+  );
+}
+
 export function RunReviewScreen() {
   const navigate = useNavigate();
   const { client } = useZino();
   const [busy, setBusy] = useState<'now' | 'custom' | null>(null);
   const [err, setErr] = useState<string | null>(null);
-  const [asOf, setAsOf] = useState('');
-  const [from, setFrom] = useState('');
-  const [to, setTo] = useState('');
+  // Two custom runs, never mixed. "Replay" = one date, the morning to stand on;
+  // "Period" = from–to, the span to analyse. Each sends only its own fields.
+  const [mode, setMode] = useState<'replay' | 'period'>('replay');
+  const [asOfInput, setAsOf] = useState('');
+  const [fromInput, setFrom] = useState('');
+  const [toInput, setTo] = useState('');
+  const asOf = mode === 'replay' ? asOfInput : '';
+  const from = mode === 'period' ? fromInput : '';
+  const to = mode === 'period' ? toInput : '';
 
   // The data's own span, so a window cannot be set where there is nothing to
   // compare: a start before the first claim leaves no baseline, and a run on
@@ -47,9 +69,9 @@ export function RunReviewScreen() {
   const baseTo = recentFrom ? addDays(recentFrom, -1) : '';
   const dateErr =
     from && effectiveTo && from > effectiveTo
-      ? 'The window must start before it ends.'
-      : to && asOf && to > asOf
-        ? '"Window to" cannot be after "data as of".'
+      ? 'The period must start before it ends.'
+      : mode === 'period' && (!from || !to)
+        ? null
         : dataFrom && baseFrom && baseFrom < dataFrom
           ? `The 8-week baseline before ${shortDate(recentFrom)} needs data from ${shortDate(baseFrom)}, but the data begins ${shortDate(dataFrom)}. Start the window on or after ${shortDate(addDays(dataFrom, 56))}.`
           : null;
@@ -61,11 +83,10 @@ export function RunReviewScreen() {
       // Every field on the activity is optional; send only the ones the
       // reviewer set, so a plain run is a genuinely empty submission.
       const data: Record<string, string> = {};
-      if (custom) {
-        // "Window to" is the ceiling; "data as of" only matters when no window end is given.
-        if (asOf && !to) data.review_as_of__review = asOf;
-        if (from) data.review_from__review = from;
-        if (to) data.review_to__review = to;
+      if (custom && mode === 'replay') data.review_as_of__review = asOf;
+      if (custom && mode === 'period') {
+        data.review_from__review = from;
+        data.review_to__review = to;
       }
       const res = await client.startInstance(WORKFLOW, ACT.REVIEW, data);
       if (res.instance_id) navigate(`/c/${res.instance_id}`);
@@ -137,31 +158,48 @@ export function RunReviewScreen() {
           <div className="min-w-0 flex-1">
             <p className="font-semibold text-ink">Custom run</p>
             <p className="mt-0.5 text-sm text-muted">
-              Replay a past morning, or point the review at a specific period. Leave a date blank to
-              use the default.
+              Choose one of the two.
               {dataFrom && dataTo ? ` Data available ${shortDate(dataFrom)} – ${shortDate(dataTo)}, ${dataTo.slice(0, 4)}.` : ''}
             </p>
           </div>
         </div>
 
-        <div className="mt-4 grid gap-3 sm:grid-cols-3">
-          <div>
-            <Label>Data as of</Label>
-            <Input type="date" value={asOf} onChange={setAsOf} />
-            <p className="mt-1 text-[11px] text-faint">Ignore anything after this date. Try {shortDate(QUIET_MORNING_AS_OF)} for a quiet morning.</p>
-          </div>
-          <div>
-            <Label>Window from</Label>
-            <Input type="date" value={from} onChange={setFrom} />
-            <p className="mt-1 text-[11px] text-faint">Start of the period Ava analyses.</p>
-          </div>
-          <div>
-            <Label>Window to</Label>
-            <Input type="date" value={to} onChange={setTo} />
-            <p className="mt-1 text-[11px] text-faint">End of the period. Defaults to "data as of".</p>
-          </div>
+        <div className="mt-4 grid gap-3 sm:grid-cols-2">
+          <ModeCard
+            active={mode === 'replay'}
+            onClick={() => setMode('replay')}
+            title="Replay a past morning"
+            body="One date. The review runs as if it were that morning: the 6 weeks before it, compared with the 8 weeks before those. Anything after the date is ignored."
+          />
+          <ModeCard
+            active={mode === 'period'}
+            onClick={() => setMode('period')}
+            title="Analyse a specific period"
+            body="A start and an end. That span is compared with the 8 weeks before it starts. Anything after the end is ignored."
+          />
         </div>
 
+        {mode === 'replay' ? (
+          <div className="mt-4 sm:max-w-xs">
+            <Label>Review as of</Label>
+            <Input type="date" value={asOfInput} onChange={setAsOf} />
+            <p className="mt-1 text-[11px] text-faint">Try {shortDate(QUIET_MORNING_AS_OF)} for a morning with no findings.</p>
+          </div>
+        ) : (
+          <div className="mt-4 grid gap-3 sm:grid-cols-2">
+            <div>
+              <Label>From</Label>
+              <Input type="date" value={fromInput} onChange={setFrom} />
+              <p className="mt-1 text-[11px] text-faint">First day of the period.</p>
+            </div>
+            <div>
+              <Label>To</Label>
+              <Input type="date" value={toInput} onChange={setTo} />
+              <p className="mt-1 text-[11px] text-faint">Last day. Up to 12 weeks after "From".</p>
+            </div>
+          </div>
+        )}
+
         <p className="mt-3 text-xs text-muted">
           {dateErr ? (
             <span className="text-bad">{dateErr}</span>
@@ -184,7 +222,7 @@ export function RunReviewScreen() {
             kind="secondary"
             onClick={() => run(true)}
             busy={busy === 'custom'}
-            disabled={busy !== null || !!dateErr || (!asOf && !from && !to)}
+            disabled={busy !== null || !!dateErr || (mode === 'replay' ? !asOf : !from || !to)}
           >
             <CalendarRange className="h-4 w-4" />
             Run with these dates