diff --git a/source/css/_common/scaffolding/base.styl b/source/css/_common/scaffolding/base.styl
index e9a9f99..0042acb 100644
--- a/source/css/_common/scaffolding/base.styl
+++ b/source/css/_common/scaffolding/base.styl
@@ -9,6 +9,7 @@ html, body {
 
 body {
   background: var(--body-bg-color);
+  box-sizing: border-box;
   color: var(--text-color);
   font-family: $font-family-base;
   font-size: $font-size-base;