From 5b58952e1e9c78a6f94ebaf13844f4101da03c2e Mon Sep 17 00:00:00 2001
From: Aaron Dodson <aaron.dodson@raspberrypi.org>
Date: Thu, 8 Jan 2026 10:18:55 -0800
Subject: [PATCH] feat!: Use box-sizing: border-box by default

---
 core/css.ts | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/core/css.ts b/core/css.ts
index 503b6362ba2..37de8e761e1 100644
--- a/core/css.ts
+++ b/core/css.ts
@@ -59,6 +59,15 @@ export function inject(hasCss: boolean, pathToMedia: string) {
  * The CSS content for Blockly.
  */
 let content = `
+:is(
+  .injectionDiv,
+  .blocklyWidgetDiv,
+  .blocklyDropdownDiv,
+  .blocklyTooltipDiv,
+) * {
+  box-sizing: border-box;
+}
+
 .blocklySvg {
   background-color: #fff;
   outline: none;