feat!: Use box-sizing: border-box by default #9556
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maribethb
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Jan 19, 2026
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LGTM, I added instructions to the PR description, please double check them for me :)
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The basics
The details
Resolves
Fixes #9205
Proposed Changes
This PR updates Blockly's CSS to use
box-sizing: border-boxby default for the core Blockly elements.Breaking Changes
If you add custom elements as children of the blockly containers, ensure that your custom elements' styling is compatible with
box-sizing: border-box. If you do not add custom elements as children of the blockly containers (such as the injection div) then this change is unlikely to affect you.