I’m very much into this question myself! ??
Nobita, I tried changing the Fluid Max Width (px) as suggested, but this does not impact on the width of the sidebars, only on the width of the entire box layout. So I think you misunderstood the question posed by songuino?
I can see that one might choose different settings for the width of the left sidebar, in this customisation column. For example, mine is set to 180 px. When the screen is 1280, I think that width is fitting.
https://gestaltudvikling.dk/
But as the screen/window becomes smaller, the 180 width becomes less fitting. Is it possible to make the .lsidebar width responsive, like the .rsidebar width is? So that they’d be equal to each other?
I recognise that this might be difficult, because div.yui-u:nth-child(1) should then float left to meet the width of lsidebar.
I’m not sure if that’s possible, in fact?