diff --git a/packages/theme-chalk/src/container.scss b/packages/theme-chalk/src/container.scss
index 3432a728c..df7b2aff3 100644
--- a/packages/theme-chalk/src/container.scss
+++ b/packages/theme-chalk/src/container.scss
@@ -4,6 +4,7 @@
   display: flex;
   flex-direction: row;
   flex: 1;
+  flex-basis: auto;
   box-sizing: border-box;
   min-width: 0;
 
diff --git a/packages/theme-chalk/src/main.scss b/packages/theme-chalk/src/main.scss
index ac5f785fc..48f7ff3bb 100644
--- a/packages/theme-chalk/src/main.scss
+++ b/packages/theme-chalk/src/main.scss
@@ -3,6 +3,7 @@
 
 @include b(main) {
   flex: 1;
+  flex-basis: auto;
   overflow: auto;
   box-sizing: border-box;
   padding: $--main-padding;