scss: be more specific with :target highlight and its children

Turns out that pseudo-classes need a selector. Yeah, that took me a bit
to figure out. Given that we really only care about tr:target, specify
the rule to be just about tr:target.

I also noticed that sometimes the background colour is doubled, making
it look a bit weird. Just applying to the td children makes that go
away, too.

Signed-off-by: Luca Zeuch <[email protected]>

Author: l-zeuch

assets/scss/common/_custom.scss

@@ -9,9 +9,9 @@ a.broken {
     text-decoration: underline;
 }
 
-:target {
-  scroll-margin-top: 10rem;
-  * {
+tr:target {
+  scroll-margin-top: 10rem !important;
+  td {
     // slightly transparent yellow
     background: rgba(255, 255, 0, 0.3);
   }