Found by Martin in https://gitlab.com/inkscape/inbox/-/issues/3268#note_378199615 #### Summary: Inkscape should handle invalid property names like those that begin with `--` or a number, e.g. `0color`. Note that in SVG2/CSS3, some of these are [now valid](https://www.w3.org/TR/css-syntax-3/#ident-token-diagram). https://www.w3.org/TR/CSS21/syndata.html#declaration > A user agent must ignore a declaration with an invalid property name or an invalid value. Every CSS property has its own syntactic and semantic restrictions on the values it accepts. where ignore links to https://www.w3.org/TR/CSS21/syndata.html#ignore, which treats `h1 { color: red; rotation: 70minutes }` as `h1 { color: red }` #### Steps to reproduce: - open [inkscape-css-invalid-ident.svg](/uploads/9e0bd5f2aafe86f517c1f346670fbe0c/inkscape-css-invalid-ident.svg) in Inkscape  ```xml <?xml version="1.0" encoding="UTF-8" standalone="no"?> <svg height="100" width="100" viewBox="0 0 100 100" xmlns="http://www.w3.org/2000/svg" xmlns:svg="http://www.w3.org/2000/svg"> <style> rect { fill:red; 0color:green; stroke:blue; } </style> <rect width="50" height="50" /> </svg> ``` #### What happened? - style tag is ignored and rect remains unset #### What should have happened? - only the invalid property is ignored Note: https://www.w3.org/TR/CSS21/syndata.html#value-def-identifier defines invalid properties in CSS2.1, https://www.w3.org/TR/css-syntax-3/#ident-token-diagram defines invalid properties for CSS syntax 3 (laxer rules) #### Version Info: - Inkscape 0.92.3 (2405546, 2018-03-11) Linux Mint 19.1 - Inkscape 1.1-dev (bd77302e35, 2020-07-12, custom) Linux Mint 19.1 Search terms for duplicate search: `css` and `style`