Header disappeared – Twentyeleven theme

I’m fresh to wordpress and looking for some advice on why my header has disappeared and how I can retrieve it.

I’m using a child theme to customise the TwentyEleven theme.

I was attempting to change the width of the header and followed some advice in the forum about changing the page width as a thoroughfare with this code in the child theme stylesheet:

#page {
margin: 1.5em auto;
max-width: 1050px;
}

Not sure this has affected the header?

Obviously I’m super new so really appreciate any advice, my site is https://www.winterplan.net.