diff --git a/flex/07-flex-layout-2/solution/solution.css b/flex/07-flex-layout-2/solution/solution.css
index 3ca1867..6355f53 100644
--- a/flex/07-flex-layout-2/solution/solution.css
+++ b/flex/07-flex-layout-2/solution/solution.css
@@ -19,6 +19,7 @@ body {
 .sidebar {
   width: 300px;
   background: royalblue;
+  box-sizing: border-box;
 }
 
 .card {
diff --git a/flex/07-flex-layout-2/style.css b/flex/07-flex-layout-2/style.css
index 7516f6b..6caf04c 100644
--- a/flex/07-flex-layout-2/style.css
+++ b/flex/07-flex-layout-2/style.css
@@ -19,6 +19,7 @@ body {
 .sidebar {
   width: 300px;
   background: royalblue;
+  box-sizing: border-box;
 }
 
 .card {