Depending on the theme you are using, there may be a setting for “clean embeds” or “strict embeds”.
SIRvb has a snippet with a bunch of different options:
To just get rid of the left vertical line for embeds, this should do:
body {
--embed-background: inherit;
--embed-border-left: none;
--embed-padding: 0 0 0 0;
--embed-font-style: inherit;
}
But for export to PDF, we need to wrap it in some more CSS:
@media print {
body {
--embed-background: inherit;
--embed-border-left: none;
--embed-padding: 0 0 0 0;
--embed-font-style: inherit;
}
}