I use the html tag <mark>
and define the css attributes via css snippets.
The basic information comes from here (once again, by @Moonbase59 )
Then I added some extras. For example, for the two “boxes” I added this:
:root
{
--note-blue-l: rgba(80,180,210,0.1);
--note-blue-d: rgba(202,240,255,0.08);
}
.theme-light {
--note-blue-highlight-bg: var(--note-blue-l);
}
.theme-dark {
--note-blue-highlight-bg: var(--note-blue-d);
}
/* MY NOTES */
mark.note-blue {
display: block;
background-color: var(--note-blue-highlight-bg) !important;
font-size: 12px;
border-radius: 8px;
padding: 10px;
margin-left: 30%;
opacity: 80%;
}
mark.margin-note {
display: block;
background-color: transparent !important;
border: 1px solid;
border-color: var(--text-faint);
border-radius: 8px;
color: var(--text-muted);
font-size: 12px;
padding: 10px;
margin-left: 30%;
margin-top: 8px;
margin-bottom: 8px;
}