Hi there!
You wrote you are using the "Dynamik" child theme for Genesis.
Please make sure the CSS Minifying is disabled -- see under "Dynamik Design Options", the "Body" tab, the last option. You can enable it again __after__ making your settings appear.
Ok, next step here is: go to "Dynamik Custom" settings and use the tab "CSS", there place in your CSS code you posted, like this:
#subnav .space-left {
margin-left: 400px !important;
margin-right: 0 !important;
}
Next step: double check in your menu if the entered CSS classes appear something like that in the input field:
twitter-prl-s24 space-left
Please note the actual space before "space-left".
If I were using these steps I just got it all to work and display. I hope you'll get it to work too :-)
Thanks, Dave :)