Adjust styles on dataset pages to accommodate smaller desktop screen sizes

[jasonlally]

We haven't addressed the mobile use case and this issue is purposefully not about that. We'll inform how to handle the explorer on mobile devices through through additional research and log those as issues.

We do want to make sure we accommodate desktops of reasonable varying widths. There are some simple style changes we can make to make sure the charts scale without overlapping the navigation bar.

@jbonaguro - can you provide a screenshots here that indicates how small/wide your screen was when you experienced the issue you reported?