How adjust width of left panel?

This will be complicated as you will need to dive into the browser Developer Tools to inspect the code and figure out all the areas that need to change.

At it's most simple, you need to change the width for both the container and tab-panel styles in the skin editor. 

In addition there is a min-width set that you can't access through the user interface. So you'd create a custom css file and add the following to the file, specifying the same width you used for the container and tab-panel styles. Then add the file under Layout > User Assets.

.RH-LAYOUT-LEFTPANEL-container {
    min-width: 120px;
}

But when you generate it, you then find the Index and Glossary tabs don't display. So you'll have to inspect the output again to figure out what you need to change to get the tabs to display. Then you'd generate again and check if there were more changes you need to figure out.

So as I said, complicated, but doable if you have advanced css skills.

@LMS_90 Somehow your post got missed. Hopefully you found the answer but if not and for the benefit of others, this image shows what you need to adjust.

I have used points as the unit of measure but you can use whatever you prefer. 

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