Thanks a lot for that piece of code @katklopp.
I am not used to tweak CSS stylesheets. Could you detail where I need to put that code in order to have full width posts? I now got something like this in style.css:
.page-template-fullwidth .content-wrap { width: 100%; }
#content {
float: left;
width: 100%;
margin: 0 0 30px;
}
with the rest of you code under .entry-header.
And I am sure that’s not the right way to go ??