diff --git a/apps/web/src/styles/base.css b/apps/web/src/styles/base.css
index 44ad026..f31836a 100644
--- a/apps/web/src/styles/base.css
+++ b/apps/web/src/styles/base.css
@@ -2793,6 +2793,15 @@ ul[data-type='task_list'] li p:last-of-type {
   height: auto;
 }
 
+/* Plugin-fallback SVGs (e.g. Excalidraw sketches inlined by the api's
+   fallback renderer) carry fixed pixel width/height attributes; without this
+   they overflow narrow viewports — the img rule above does not match inline
+   <svg> elements. */
+.dt-plugin-fallback svg {
+  max-width: 100%;
+  height: auto;
+}
+
 /* Effective-permissions inspector (issue #57) */
 .inspector__intro {
   color: var(--color-text-muted);