My Calender rendering to the left within a Section

I am new to My Calendar and can use CSS reasonably well.

When I place My Calendar on a page using the shortcode it renders to the left within a section. I would like it centered on the page. I can fudge things by applying a margin right: -100px; margin-left: 100px; but this is not ideal, then write some css for smaller screen sizes like mobile phone.

Why does it render to the left?, anyone else with this problem?

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