Left Nav/Sidebar Width on Mobile

I previously asked about this issue and thought it was fixed, but it’s not. Sorry to bother!

I’m using the left navigation but the client wants the width to be more like 250px and I added this CSS adjusting the width and the left margin of main:
.html_header_sidebar #top #header {
max-width: 250px !important;
}
.html_header_left #main {
margin-left: 250px !important;
}

The smaller mobile layout gets screwed up with this and Ismeal said to add this:
@media only screen and (min-width: 989px) {
.html_header_sidebar #top #header {
max-width: 250px !important;
}
.html_header_left #main {
margin-left: 250px !important;
}
}

But I’m still getting the same problem. Screenshot: http://grab.by/C2Hs
Any ideas? Thank you in advance for any assistance.