Textarea height 100% not working

I’m working on my markdown previewer project and I have a problem.
I’m using react and react-bootstrap and I have set height of textarea to 100% but its not working. Its parent container is also set to 100%.

Please help

Here is the code: https://github.com/siddharthroy12/markdown-previewer
Here is the live website: https://markdown-live-viewer.netlify.app/

Thanks in advance.

Fixed it