Variation that yields color-matched background effect as style for links:

\rules except dash
<style>
a {
color:rgba(var(--red-val),var(--green-val),var(--blue-val),1)!important;
background-color: rgba(var(--red-val),var(--green-val),var(--blue-val),.2);
padding: 1px 2px 0px 2px;
text-decoration: none;
}
.myred {
--red-val: 255;
--green-val: 50;
--blue-val: 50;
color:rgba(var(--red-val),var(--green-val),var(--blue-val),1);
}
.mygreen {
--red-val: 20;
--green-val: 180;
--blue-val: 20;
color:rgba(var(--red-val),var(--green-val),var(--blue-val),1);
}
.mybluebeige {
background-color:beige; padding: .5em;
--red-val: 80;
--green-val: 80;
--blue-val: 250;
color:rgba(var(--red-val),var(--green-val),var(--blue-val),1);
}
</style>
@@.myred
Red text with link to [[$:/core/ui/SideBar/Open]]
@@
@@.mygreen Green text and [[link|$:/core/ui/SideBar/Open]]@@ —
@@.mybluebeige Blue-on-beige with [[link|$:/core/ui/SideBar/Open]] @@
Thanks, @Mohammad!