Merge branch 'fix/book-dark-code' into gh-pages

This corresponds to git#2122

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

assets/sass/book2.scss

@@ -1,4 +1,8 @@
 .edition2 {
+  /* Book code colors (light mode defaults) */
+  --book-code-color: #333;
+  --book-code-bg: #eee;
+  --book-code-border: #f5f5f5;
   * {
     box-sizing: border-box;
   }
@@ -474,11 +478,11 @@
   }
 
   pre {
-    background: #eee;
+    background: var(--book-code-bg);
 
     code {
       display: inline;
-      background: #eee;
+      background: var(--book-code-bg);
       border: 0;
     }
   }
@@ -488,14 +492,14 @@
     overflow-x: auto;
     font-size: 0.9em;
     line-height: 120%;
-    color: #333;
+    color: var(--book-code-color);
   }
 
   code { /* inline code */
     padding: 0;
-    color: #333;
-    background: #eee;
-    border: 1px solid #f5f5f5;
+    color: var(--book-code-color);
+    background: var(--book-code-bg);
+    border: 1px solid var(--book-code-border);
   }
 
   table pre { /* code blocks within tables */

assets/sass/dark-mode.scss

@@ -83,6 +83,13 @@
                 z-index: -1;
             }
 
+            /* Book pages: code colors */
+            .edition2 {
+                --book-code-color: #{$fixed-width-font-color};
+                --book-code-bg: #{$no-changes-bg-color};
+                --book-code-border: #{$pre-border};
+            }
+
             img {
                 filter: brightness(.6) contrast(1.2);
             }