use vendorized colors to make mixins work

Author: msbt

src/crate/theme/rtd/crate/static/css/ng/index.scss

@@ -2,4 +2,3 @@
 @import "layout";
 @import "furo";
 @import "page-tools";
-@import "colors";

src/crate/theme/rtd/crate/static/vendor/furo/styles/base/_theme.sass

@@ -11,3 +11,51 @@ body
   @include default-admonition(#651fff, "abstract")
   @include default-topic(#14B8A6, "pencil")
 
+  @include colors
+
+.only-light
+  display: block !important
+html body .only-dark
+  display: none !important
+
+// Ignore dark-mode hints if print media.
+@media not print
+  // Enable dark-mode, if requested.
+  body[data-theme="dark"]
+    @include colors-dark
+
+    html & .only-light
+      display: none !important
+    .only-dark
+      display: block !important
+
+  // Enable dark mode, unless explicitly told to avoid.
+  @media (prefers-color-scheme: dark)
+    body:not([data-theme="light"])
+      @include colors-dark
+
+      html & .only-light
+        display: none !important
+      .only-dark
+        display: block !important
+
+//
+// Theme toggle presentation
+//
+body[data-theme="auto"]
+  .theme-toggle svg.theme-icon-when-auto-light
+    display: block
+
+  @media (prefers-color-scheme: dark)
+    .theme-toggle svg.theme-icon-when-auto-dark
+      display: block
+    .theme-toggle svg.theme-icon-when-auto-light
+      display: none
+
+body[data-theme="dark"]
+  .theme-toggle svg.theme-icon-when-dark
+    display: block
+
+body[data-theme="light"]
+  .theme-toggle svg.theme-icon-when-light
+    display: block

src/crate/theme/rtd/crate/static/vendor/furo/styles/variables/_index.sass

@@ -5,4 +5,4 @@
 @import "spacing"
 @import "icons"
 @import "admonitions"
-//@import "colors"
+@import "colors"

…heme/rtd/crate/static/css/ng/colors.scss …vendor/furo/styles/variables/colors.scsssrc/crate/theme/rtd/crate/static/css/ng/colors.scss renamed to src/crate/theme/rtd/crate/static/vendor/furo/styles/variables/colors.scss src/crate/theme/rtd/crate/static/css/ng/colors.scss renamed to src/crate/theme/rtd/crate/static/vendor/furo/styles/variables/colors.scss

@@ -21,7 +21,7 @@ body[data-theme="light"] {
   }
 }
 
-[data-theme="light"] {
+@mixin colors {
   // API documentation
   --color-api-background: var(--color-background-hover--transparent);
   --color-api-background-hover: var(--color-background-hover);
@@ -175,7 +175,7 @@ body[data-theme="light"] {
   --link-toc: #000;
 }
 
-[data-theme="dark"] {
+@mixin colors-dark {
   // API documentation
   --color-api-background: var(--color-background-hover--transparent);
   --color-api-background-hover: var(--color-background-hover);