Add: Theme - PDF contents darkmode

CREDITS

@@ -175,6 +175,11 @@ W: https://github.com/MrOtherGuy/firefox-csshacks
 C: Copyright (c) 2018 MrOtherGuy
 L: MPL 2.0
 
+N: Firefox Custom CSS
+W: https://github.com/hakan-demirli/Firefox_Custom_CSS
+C: Copyright (c) 2022 hakan-demirli
+L: MIT
+
 N: Fluent UI System Icons
 W: https://github.com/microsoft/fluentui-system-icons
 C: Copyright (c) 2020 Microsoft Corporation

__tests__/moz_document.test.scss

@@ -6,6 +6,9 @@
   @include test("simple") {
     @include assert {
       @include output {
+        @include moz-document(unobservable-document) {
+          @include example;
+        }
         @include moz-document(url "about:downloads") {
           @include example;
         }
@@ -17,6 +20,9 @@
         }
       }
       @include expect {
+        @-moz-document #{unobservable-document()} { // Invalid function name.
+          @include example;
+        }
         @-moz-document url("about:downloads") {
           @include example;
         }

css/leptonContent.css

@@ -1640,6 +1640,23 @@
         box-shadow: 0 0 0 3px color-mix(in srgb, var(--in-content-primary-button-background-hover) 80%, transparent) !important;
       }
     }
+    @supports -moz-bool-pref("userContent.page.dark_mode.pdf") {
+      @-moz-document unobservable-document() {
+        @-moz-document regexp("^(?!.*\\.pdf\\?n).*") {
+          #outerContainer {
+            --sidebaritem-bg-color: #38383d;
+            --uc-pdf-dark-filter: grayscale(10%) invert(90%);
+          }
+          #sidebarContainer > #sidebarContent > #thumbnailView .thumbnailImage {
+            filter: var(--uc-pdf-dark-filter);
+            box-shadow: 0 0 0 1px hsla(0deg, 0%, 100%, 0.5), 0 2px 8px hsla(0deg, 0%, 100%, 0.3) !important;
+          }
+          #viewerContainer > #viewer > .page > .canvasWrapper > canvas {
+            filter: var(--uc-pdf-dark-filter);
+          }
+        }
+      }
+    }
   }
 }
 /** Fully Proton Mode *********************************************************/

src/contents/_dark_mode.scss

@@ -2,4 +2,23 @@
   @import "dark_mode/addons_org";
   @import "dark_mode/support_org";
   @import "dark_mode/accounts_com";
+
+  @include Option("userContent.page.dark_mode.pdf") {
+    @include moz-document(unobservable-document) {
+      @include moz-document(regexp "^(?!.*\\.pdf\\?n).*") {
+        #outerContainer {
+          --sidebaritem-bg-color: #38383D;
+          --uc-pdf-dark-filter: grayscale(10%) invert(90%);
+        }
+
+        #sidebarContainer > #sidebarContent > #thumbnailView .thumbnailImage {
+          filter: var(--uc-pdf-dark-filter);
+          box-shadow: 0 0 0 1px hsla(0, 0%, 100%, 0.5), 0 2px 8px hsla(0, 0%, 100%, 0.3) !important;
+        }
+        #viewerContainer > #viewer > .page > .canvasWrapper > canvas {
+          filter: var(--uc-pdf-dark-filter);
+        }
+      }
+    }
+  }
 }

src/utils/_moz_document.scss

@@ -1,7 +1,7 @@
 @mixin moz-document($urlList...) {
   $result: ();
   @each $prefix, $urlPattern in $urlList {
-    $result: append($result, #{$prefix}("#{$urlPattern}"), $separator: comma);
+    $result: append($result, #{$prefix}(if($urlPattern, "#{$urlPattern}", null)), $separator: comma);
   }
 
   @#{-moz-document} #{$result} {

user.js

@@ -206,6 +206,7 @@ user_pref("userChrome.rounding.square_tab",           false);
 
 // user_pref("userContent.page.proton_color.dark_blue_accent", true);
 // user_pref("userContent.page.proton_color.system_accent",    true);
+// user_pref("userContent.page.dark_mode.pdf",                 true);
 // user_pref("userContent.page.monospace",                     true);
 
 // == Theme Default Settings ===================================================