Migrate :target rules to use CSS variables

Author: GuillaumeGomez

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

@@ -1269,6 +1269,8 @@ h3.variant {
 
 :target {
 	padding-right: 3px;
+	background-color: var(--target-background-color);
+	border-right: 3px solid var(--target-border-color);
 }
 
 .notable-traits-tooltip {

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

@@ -63,6 +63,8 @@ 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);
+	--target-background-color: rgba(255, 236, 164, 0.06);
+	--target-border-color: rgba(255, 180, 76, 0.85);
 	--rust-logo-filter: drop-shadow(1px 0 0px #fff)
 		drop-shadow(0 1px 0 #fff)
 		drop-shadow(-1px 0 0 #fff)
@@ -168,11 +170,6 @@ details.rustdoc-toggle > summary::before {
 	color: #788797;
 }
 
-:target {
-	background: rgba(255, 236, 164, 0.06);
-	border-right: 3px solid rgba(255, 180, 76, 0.85);
-}
-
 .search-failed a {
 	color: #39AFD7;
 }

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

@@ -58,6 +58,8 @@
 	--test-arrow-background-color: rgba(78, 139, 202, 0.2);
 	--test-arrow-hover-color: #dedede;
 	--test-arrow-hover-background-color: #4e8bca;
+	--target-background-color: #494a3d;
+	--target-border-color: #bb7410;
 	--rust-logo-filter: drop-shadow(1px 0 0px #fff)
 		drop-shadow(0 1px 0 #fff)
 		drop-shadow(-1px 0 0 #fff)
@@ -90,11 +92,6 @@ details.rustdoc-toggle > summary::before {
 	filter: invert(100%);
 }
 
-:target {
-	background-color: #494a3d;
-	border-right: 3px solid #bb7410;
-}
-
 .search-failed a {
 	color: #0089ff;
 }

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

@@ -58,6 +58,8 @@
 	--test-arrow-background-color: rgba(78, 139, 202, 0.2);
 	--test-arrow-hover-color: #f5f5f5;
 	--test-arrow-hover-background-color: #4e8bca;
+	--target-background-color: #fdFfd3;
+	--target-border-color: #ad7c37;
 	--rust-logo-filter: initial;
 	/* match border-color; uses https://codepen.io/sosuke/pen/Pjoqqp */
 	--crate-search-div-filter: invert(100%) sepia(0%) saturate(4223%) hue-rotate(289deg)
@@ -83,11 +85,6 @@ body.source .example-wrap pre.rust a {
 	background: #eee;
 }
 
-:target {
-	background: #FDFFD3;
-	border-right: 3px solid #AD7C37;
-}
-
 .search-failed a {
 	color: #3873AD;
 }