diff --git a/static/src/styles/components/overlays/_overlays.scss b/static/src/styles/components/overlays/_overlays.scss
index 191336a..88b3636 100644
--- a/static/src/styles/components/overlays/_overlays.scss
+++ b/static/src/styles/components/overlays/_overlays.scss
@@ -1736,6 +1736,8 @@
 .mobile-panel-sheet--conversation,
 .mobile-panel-sheet--workspace {
     background: var(--claude-left-rail);
+    width: min(420px, 65vw);
+    max-width: 65vw;
 }
 
 .mobile-panel-sheet--focus {