NavPanel_splitter / dijitSplitter initial startup position w/ dojoxToggleSplitterLeft

Please help. I’m attempting to customize a Dojo page with adjustable dijitSplitter separator, the splitter is adjustable by left-clicking (onmousedown) and sliding it left/right. This functionality works, however every time the page is loaded the splitter resets back to the original startup position every time the page is loaded. I need this splitter to start in the correct spot every time, instead of having to move it around every single time the page is opened. This NavPanel “width” parameter doesn’t appear to be in the CSS config file. Where / How can I manually define the initial startup position of a NavPanel_splitter / dijitSplitter / dojoToggleSplitter ? Any help is appreciated.

Update: another non-working test was to use: idHtml_NavPanel {width: 300px !important} — this sets the correct width and puts the splitter where it needs to be, but the width is hardcorded at that point, the toggle splitter function no longer works. I need to find a way to not use !important here so that the toggle still works, with the correct initial startup width of the navpanel.