How to override SASS variables in the default theme without creating a custom theme?

Hi. I am missing something obvious I think.

I have read the themeing guide, can create a custom theme, set variables etc.

However I would like to just use the ext-theme-gray and change a few variables without hacking the library theme files themselves. So, I set the theme via the sencha.cfg file and have the default gray theme. All good so far.

Now, following the cited example of setting a base color I created a file myapp/sass/var/Component.scss and set $base-color: #00f !default; as a test. I then rebuilt a production build via sencha cmd but the base color remains #ccc.

What am I missing please?

Thanks,

Murray

How to override SASS variables in the default theme without creating a custom theme?