[csswg-drafts] [css-backgrounds][css-overflow] Is viewport's background painted behind viewport's scrollbars? (#12744)

Loirooriol has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-backgrounds][css-overflow] Is viewport's background painted behind viewport's scrollbars? ==
If both the background and the overflow get propagated to the viewport, what happens?

https://drafts.csswg.org/css-backgrounds-3/#body-background
https://drafts.csswg.org/css-overflow-3/#overflow-propagation

```html
<!DOCTYPE html>
<iframe width="100" height="100" srcdoc="
  <style>
  :root {
    background: cyan;
    scrollbar-color: rgb(255, 0, 255, 0.5) rgb(255, 0, 255, 0.5);
    overflow: scroll;
  }
  ::-webkit-scrollbar { background-color: rgb(255, 0, 255, 0.5); width: 12px; height: 12px; }
  </style>
"></iframe>
```

| Gecko | Blink | WebKit |
| - | - | - |
| <img width="115" height="114" src="https://github.com/user-attachments/assets/e1701283-3eeb-4d3b-94a7-9a4941d37f89" /> | <img width="115" height="114" src="https://github.com/user-attachments/assets/36e8ae63-e5d6-48a9-b9c9-74d39cef019d" /> | <img width="115" height="114" src="https://github.com/user-attachments/assets/6586acd2-7926-4153-9531-ee7181ff97db" /> |

I would expect the background to be painted below the scrollbar like in a normal element, and be able to change that with `background-clip: content-box` (but that never works, see #11169)

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/12744 using your GitHub account


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Received on Saturday, 6 September 2025 12:25:43 UTC