diff --git a/src/runtime-showcase/components/layout/layout.m.css b/src/runtime-showcase/components/layout/layout.m.css
index 16e6a71..f11ec84 100644
--- a/src/runtime-showcase/components/layout/layout.m.css
+++ b/src/runtime-showcase/components/layout/layout.m.css
@@ -72,7 +72,7 @@
 .presetFixedNav .aside {
   position: fixed;
   top: 0;
-  height: 100%;
+  height: calc(100% - var(--showcase-ui-header-height, 64px));
   max-height: 100vh;
   margin-top: var(--showcase-ui-header-height, 64px);
 }