diff --git a/less/main.less b/less/main.less
index 819d480a1f1..05d436c7eba 100644
--- a/less/main.less
+++ b/less/main.less
@@ -9,6 +9,14 @@ body {
   background-color: @bodyBG;
 }
 
+html {
+  box-sizing: border-box;
+}
+
+*, *:before, *:after {
+  box-sizing: inherit;
+}
+
 #windowContainer {
   color: @windowContainerFG;
 }