Remove left Navigation when form opens

[Mapleleaf]

Hello,

when I want to remove the left Navigation I often use this code on pages:

<style>
#sideNavBox{display: none !important;}
#contentBox{margin-left: 20px !important;}
</style>

I put it in a script-editor webpart. Can I implement the code in the css of a form? Will this work? Is the syntax the same as in script-Editor-webpart?

[AlexZver]

Dear Mapleleaf,

Please add these CSS rules in the CSS Editor without "style" tag, like this:

Screenshot_139.png (25.83 KiB) Viewed 2300 times