Remove background tint from verbatim/code spans

Inline code kept a light secondary/primary-colour background tint,
which stands out on posters (and prints as grey boxes). Keep the
coloured foreground but make the background transparent.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Change-Id: I03d27bb66259a5cc515bfcf949886fcac2f17abd
diff --git a/inst/rmarkdown/templates/posterdown_ids/resources/template.html b/inst/rmarkdown/templates/posterdown_ids/resources/template.html
index 88cb7f0..2da84d1 100644
--- a/inst/rmarkdown/templates/posterdown_ids/resources/template.html
+++ b/inst/rmarkdown/templates/posterdown_ids/resources/template.html
@@ -361,7 +361,7 @@
 code {
 font-size: $if(codechunk_textsize)$$codechunk_textsize$$else$20pt$endif$;
 font-family: "Fira Mono", monospace;
-background-color: $if(secondary_colour)$$secondary_colour$24$else$#00808024$endif$;
+background-color: transparent;
 color: $if(secondary_colour)$$secondary_colour$$else$#008080$endif$;
 padding: 1.2mm;
 line-height: 1;
@@ -386,7 +386,7 @@
 code {
 font-size: 1em;
 font-family: monospace;
-background-color: $if(secondary_colour)$$secondary_colour$24$else$#00808024$endif$;
+background-color: transparent;
 color: $if(primary_colour)$$primary_colour$$else$#f57c14$endif$;
 padding: 1.2mm;
 border-radius: 2mm;