Ok now I get what want to achive.
To wrap it and center horizontally (I assume you want to do it) you need to
margin: 0 auto;
to .container
NOTE: there will not be any scroll horizontal because of position: fixed;
TIP: If you create css do tree of selectors in this case
.rectangle{}
and then
.rectangle .container{}
here is example JSFIDDLE
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solved Container not wrapping the content [closed]