dark-mode: fix code contrast on Book pages

Book pages inherited light-mode code colors in dark mode, resulting in poor contrast for inline and block code.

Move the Book-specific fix into dark-mode.scss, mirroring the existing light-mode selector scope and using existing theme variables. This avoids layout-related overrides and follows established dark-mode patterns (as used for man-pages in f3771e3).

Author: Subhajit-das21

assets/sass/book.scss

@@ -174,25 +174,4 @@ ol.book-toc {
   .book-wrapper {
     margin-right: 0;
   }
-}
-
-/* --------------------------------------------------
-   Fix: Dark mode styling for code blocks in Book pages
-   -------------------------------------------------- */
-
-html[data-theme="dark"] .edition2 .book code {
-  background-color: var(--color-canvas-subtle);
-  color: var(--color-fg-default);
-  padding: 0.2em 0.4em;
-  border-radius: 4px;
-}
-
-html[data-theme="dark"] .edition2 .book pre {
-  background-color: var(--color-canvas-inset);
-  color: var(--color-fg-default);
-}
-
-html[data-theme="dark"] .edition2 .book pre code {
-  background: none;
-  padding: 0;
-}
+}

assets/sass/dark-mode.scss

@@ -115,6 +115,15 @@
             #documentation #main div.verseblock pre.content {
                 color: var(--light-font-color);
                 background-color: #5e5951;
+                
+            }
+            /* Book pages: fix code contrast in dark mode */
+            .book code {
+                color: var(--fixed-width-font-color);
+            }
+
+            .book pre {
+                color: var(--fixed-width-font-color);
             }
 
             form#search {
@@ -190,10 +199,10 @@
     }
 }
 
-@include mode
-@include mode($mode: dark, $theme: '[data-theme="dark"]')
+@include mode;
+@include mode($mode: dark, $theme: '[data-theme="dark"]');
 
 @media screen and (prefers-color-scheme: dark) {
-    @include mode($mode: dark, $theme: ':not([data-theme="light"])')
-    @include mode($mode: light)
+    @include mode($mode: dark, $theme: ':not([data-theme="light"])');
+    @include mode($mode: light);
 }