Migrate rust logo filter to CSS variables

Author: GuillaumeGomez

src/librustdoc/html/static/css/rustdoc.css

@@ -378,6 +378,10 @@ img {
 	object-fit: contain;
 }
 
+.rust-logo {
+	filter: var(--rust-logo-filter);
+}
+
 .sidebar, .mobile-topbar, .sidebar-menu-toggle {
 	background-color: var(--sidebar-background-color);
 }

src/librustdoc/html/static/css/themes/ayu.css

@@ -63,6 +63,10 @@ Original by Dempfi (https://github.com/dempfi/ayu)
 	--test-arrow-background-color: rgba(57, 175, 215, 0.09);
 	--test-arrow-hover-color: #c5c5c5;
 	--test-arrow-hover-background-color: rgba(57, 175, 215, 0.368);
+	--rust-logo-filter: drop-shadow(1px 0 0px #fff)
+		drop-shadow(0 1px 0 #fff)
+		drop-shadow(-1px 0 0 #fff)
+		drop-shadow(0 -1px 0 #fff);
 }
 
 .slider {
@@ -104,13 +108,6 @@ pre, .rustdoc.source .example-wrap {
 	color: #e6e1cf;
 }
 
-.rust-logo {
-	filter: drop-shadow(1px 0 0px #fff)
-		drop-shadow(0 1px 0 #fff)
-		drop-shadow(-1px 0 0 #fff)
-		drop-shadow(0 -1px 0 #fff);
-}
-
 .sidebar .current,
 .sidebar a:hover {
 	color: #ffb44c;

src/librustdoc/html/static/css/themes/dark.css

@@ -58,6 +58,10 @@
 	--test-arrow-background-color: rgba(78, 139, 202, 0.2);
 	--test-arrow-hover-color: #dedede;
 	--test-arrow-hover-background-color: #4e8bca;
+	--rust-logo-filter: drop-shadow(1px 0 0px #fff)
+		drop-shadow(0 1px 0 #fff)
+		drop-shadow(-1px 0 0 #fff)
+		drop-shadow(0 -1px 0 #fff);
 }
 
 .slider {
@@ -70,13 +74,6 @@ input:focus + .slider {
 	box-shadow: 0 0 0 2px #0a84ff, 0 0 0 6px rgba(10, 132, 255, 0.3);
 }
 
-.rust-logo {
-	filter: drop-shadow(1px 0 0px #fff)
-		drop-shadow(0 1px 0 #fff)
-		drop-shadow(-1px 0 0 #fff)
-		drop-shadow(0 -1px 0 #fff)
-}
-
 .content .item-info::before { color: #ccc; }
 
 body.source .example-wrap pre.rust a {

src/librustdoc/html/static/css/themes/light.css

@@ -58,6 +58,7 @@
 	--test-arrow-background-color: rgba(78, 139, 202, 0.2);
 	--test-arrow-hover-color: #f5f5f5;
 	--test-arrow-hover-background-color: #4e8bca;
+	--rust-logo-filter: initial;
 }
 
 .slider {
@@ -70,12 +71,6 @@ input:focus + .slider {
 	box-shadow: 0 0 0 2px #0a84ff, 0 0 0 6px rgba(10, 132, 255, 0.3);
 }
 
-.rust-logo {
-	/* This rule exists to force other themes to explicitly style the logo.
-	 * Rustdoc has a custom linter for this purpose.
-	 */
-}
-
 .content .item-info::before { color: #ccc; }
 
 body.source .example-wrap pre.rust a {