It’s tricky since the whos online plugin attach this indicator to the pull left side (which we deactivated) and the avatar is centered vertically.
I can get closer with these modifications (put these on a css mobile stylesheet), but it’s definitely far from perfect.
.pull-left {
float: right;
}
html.whos-online-flair.mobile-view .topic-list-item.last-poster-online div.pull-left::before {
top: -15px;
left: unset;
right: -50px;
}
The easiest solution would be to deactivate this indicator on mobile and on the topic list only
html.whos-online-flair.mobile-view .topic-list-item.last-poster-online div.pull-left::before {
display: none;
}