Hi @simon
Thanks for your reply and your help.
I managed to clean up the onebox styling a bit with your suggested CSS (01.29.2018-14.27.06 - TechSmith Screencast), but there is still some undesired HTML being parsed, like an H3 header. Does the Discourse Wordpress plugin offer any hooks so I can overwrite the HTML output?
Or perhaps this is a great suggestion to improve the Discourse Wordpress plugin?
Looking forward to your reply. Thanks!
.comment-content .onebox .aspect-image,
.comment-content .onebox .source,
.comment-content .onebox p {
display: none;
}