diff --git a/packages/dockview-core/src/theme.scss b/packages/dockview-core/src/theme.scss
index 0c3d3f17a..487c344f0 100644
--- a/packages/dockview-core/src/theme.scss
+++ b/packages/dockview-core/src/theme.scss
@@ -268,6 +268,8 @@
 @mixin dockview-design-replit-mixin {
     @include dockview-drop-target-no-travel();
 
+    box-sizing: border-box;
+
     .dv-resize-container:has(> .dv-groupview) {
         border-radius: 8px;
     }
diff --git a/packages/dockview-core/src/theme/_space-mixin.scss b/packages/dockview-core/src/theme/_space-mixin.scss
index 2482b6841..cec0c291b 100644
--- a/packages/dockview-core/src/theme/_space-mixin.scss
+++ b/packages/dockview-core/src/theme/_space-mixin.scss
@@ -5,6 +5,7 @@
     --dv-tabs-and-actions-container-height: 44px;
 
     --dv-border-radius: 20px;
+    box-sizing: border-box;
 
     .dv-resize-container:has(> .dv-groupview) {
         border-radius: 8px;