diff --git a/public/index.html b/public/index.html
index 638be38..809b414 100644
--- a/public/index.html
+++ b/public/index.html
@@ -3961,6 +3961,7 @@ <h2 id="gwTitle" style="font-size:14px;display:flex;align-items:center;gap:7px">
 
 <!-- Settings-only layout and keyboard affordances. -->
 <style>
+#cfgModal .modal { width:min(1180px,96vw);max-width:96vw;height:88vh;height:88dvh;max-height:88dvh }
 #cfgModal .settings-note { padding:10px 20px;color:var(--muted);font-size:12px;line-height:1.5 }
 #cfgModal #cfgTabs { overflow-x:auto;flex-shrink:0 }
 #cfgModal #cfgTabs button { white-space:nowrap;font:inherit }
diff --git a/test/responsive-ui.test.js b/test/responsive-ui.test.js
index 7dd5d03..0afafd8 100644
--- a/test/responsive-ui.test.js
+++ b/test/responsive-ui.test.js
@@ -52,5 +52,10 @@ check('kanban.html mobile media query forces card-actions display on touch scree
   assert.ok(/\.card-actions\s*\{[^}]*display:\s*flex\s*!important/.test(media800), 'missing display: flex !important for card-actions in mobile query');
 });
 
+check('configuration modal uses the available screen (#136)', () => {
+  assert.ok(idxSrc.includes('width:min(1180px,96vw)'), 'configuration modal should use the available width');
+  assert.ok(idxSrc.includes('height:88dvh'), 'configuration modal should use the available height');
+});
+
 if (failed) { console.log(`\n${failed} test(s) failed`); process.exit(1); }
 console.log('\nAll responsive-ui tests passed');