fix(html): a selection no longer paints the pdf's hidden text layer

CHANGELOG.md

@@ -16,6 +16,10 @@ The release run heads these entries with the version and opens a fresh
 
 ## Unreleased
 
+- **Fix**: selecting text in a pdf view showed the invisible layer that carries
+  it, as a second set of glyphs over the drawn ones. That layer now stays
+  transparent under `::selection`.
+
 ## v7.1.0 - 2026-09-19
 
 - The pdf view reports the pending annotation count on

src/odr/internal/html/pdf_file.cpp

@@ -1817,6 +1817,9 @@ class HtmlServiceImpl final : public HtmlService {
       }
       // Transparent text for the selection layer line blocks.
       out.out() << ".i{color:transparent;font-family:sf,sans-serif}";
+      // A selection paints text in the highlight's own colour, which beats
+      // `transparent` and shows this layer over the glyph layer it stands for.
+      out.out() << ".i::selection,.i *::selection{color:transparent}";
       // Selection-layer run span. `overflow:hidden` clips a wider system font;
       // `.t`'s inherited `pre` blocks wrapping while preserving a run's own
       // leading/trailing space, which is real PDF content.
@@ -2287,6 +2290,11 @@ class HtmlServiceImpl final : public HtmlService {
       // height, while clipping nothing (the space is transparent).
       out.out() << ".sp{display:inline-block;"
                    "color:transparent;vertical-align:baseline}";
+      // A selection paints text in the highlight's own colour, which beats
+      // `transparent`. `*` reaches a run's own span and a search `mark`.
+      out.out() << ".i::selection,.i *::selection,"
+                   ".ov::selection,.ov *::selection,"
+                   ".sp::selection,.sp *::selection{color:transparent}";
       // A hit in the overlay is clipped away with it, so the glyphs it belongs
       // to carry the highlight instead - the whole run of them, which is as
       // narrow as the overlay can say.
@@ -2859,6 +2867,10 @@ class HtmlServiceImpl final : public HtmlService {
     }
     if (class_used[1]) {
       rule("fn", "color:transparent;");
+      // The same guard for a line the embedded font makes invisible; the dual
+      // layer's `fnN` rides a `user-select:none` run and needs none.
+      font_styles += ".fn" + n + "::selection,.fn" + n +
+                     " *::selection{color:transparent}";
     }
   }