matcha.mizu.sh aside becomes very-narrow in fullscreen here

[iambumblehead]

hello, matcha looks super cool and the single-page made-with-matcha documentation is really awesome.

I noticed that, in fullsreen here, the aside becomes very narrow while less-than-fullscreen size renders a wider aside that fixed the content more easily. Not sure if this is intentional or not but, in widescreen, the aside feels narrow here. screenshots attached,

thanks