I can just select the element with the extension but it only grabs the canvas and not the style. The canvas is self modulating / gets replaced meaning it just opens a new ad after a while, or after a refresh. However on this particular site most of the style from the start is the same only the end changes, meaning you can just block the style with "style*" and enter the start of the style in order to block it.
site.com##div[style*="display: block; position: fixed; z-index: 2147483647;"] should block every style starting with "display: block; position: fixed; z-index: 2147483647;". however nothing happens.
Im on a quest trying to block those pesky self evolving advertisements that are baked into sites. Some (all? unless the script handles more then one thing) are running with scripts that can be blocked, however iv not found a extension that allows block per content, they just lump every type by url.