Why are you setting fixed pixel width though? Clearly, this will not convert to mobile devices or even medium-sized screens (iPad's and small laptops). Map elements on pages should distribute to 100% of their content container, just like in our
sample page. Surely there are settings for this in the maps API.
There is an option in your
page > context setting to set WIDE width (100% browser width) of the content, but then you may need to use html to manage the width of elements in your content. X3 allows full flexibility to set ANY width for the page content (where you have the maps), including 100% browser width, but you will have to plan implementation of your custom content accordingly.
If you set your map widths to 100%, it would look nice like this: