IE11 does not support (Custom Properties) or CSS Grid (it uses an older, prefixed version).
To develop and test features specifically for build 9600.16428 : internet-explorer-11-0-9600-16428-final-kuyhaa
Always provide a static fallback value for CSS variables. For example: Use code with caution. Copied to clipboard 3. Emulation and Testing IE11 does not support (Custom Properties) or CSS
If you are working on a project that must support this specific legacy environment, here are the most effective ways to "develop features" for it: 1. Feature Detection and Polyfills internet-explorer-11-0-9600-16428-final-kuyhaa