Turn off Sidebar Collapse button

Hello! Here's a little struggle of mine, I am trying to hide the sidebar Expand/Collapse button on desktop, this due to some displaying issues with the Teaser slideshow which does not allow me to provide 2 sizes images to fill the whole width of the screen. Anyway, I tried some code on CSS which (to me) is correct but the buttom will still be displayed regardless of the code.

@include screen-lg {
    #sidebarRightCollapse #sidebarRightExpand {
   display: none;
    }
}

Is this correct? is there any other way to do this?

Many thanks!

Quote from muig.5

CSS

@include screen-lg {
#sidebarRightCollapse, #sidebarRightExpand {
display: none;
}
}

Thank you for that, however the button still shows!

Damn I tried to add an !important myself but forgot the ; and got a fatal error as result!

I was close but thank you so much for your input