[docs] Resize issues when navigation is open

[alexgibson]

Description

Not entirely sure if this is just the way fractal works, but if you resize the browser window when the documentation side navigation is open, the content gets cut off

Steps to reproduce

1. In a desktop browser, open https://protocol.mozilla.org/
2. Make sure the navigation side menu is open
3. Resize the browser window to < 758px wide.

Expected result

Page content should be visible.

Actual result

Page content is obscured.

Environment

Reproducible in any desktop browser.

[janbrasna]

There are some offending lines that make it better when omitted:

Given the flex reorder & 3d transformation to hide the menu and move the content I believe the correct value there was supposed to be -240px instead of 240px — then the layout seems as intended:

I'll investigate where that comes from…

[janbrasna]

Traced it to https://github.com/frctl/fractal/blob/dd6cd938653b24cd23456d10b9c28d3bc436c4c3/packages/mandelbrot/assets/scss/core/_mixins.scss#L136C43
where it should be $value * -1 or https://github.com/frctl/fractal/blob/dd6cd938653b24cd23456d10b9c28d3bc436c4c3/packages/mandelbrot/assets/scss/components/_frame.scss#L29 where the argument should be $width-sidebar * -1

That's definitely Fractal/mandelbrot bug as you can reproduce that with the currently published demo as well: https://demo.fractal.build