Page title administer page table resize

Hello. I am new to drupal and I need some help on css.
I had install page title module and I have an issue on the administer interface.

I went to /admin/settings/page-title , the interface is perfect in Garland but when I switch to my custom admin theme which width is narrow than Garland theme, the interface is too width.

I need some help in styling css. I need to narrow down the table from 965px to 750px. I try to add max-width:750px to sticky-table class but it does not work.

Please help me on how to narrow down the table. Thanks.