diff --git a/src/librustdoc/html/static/css/rustdoc.css b/src/librustdoc/html/static/css/rustdoc.css
index 67adaa8702d85..ee265b8c4b543 100644
--- a/src/librustdoc/html/static/css/rustdoc.css
+++ b/src/librustdoc/html/static/css/rustdoc.css
@@ -400,7 +400,6 @@ nav.sub {
 .source .sidebar > *:not(#sidebar-toggle) {
 	opacity: 0;
 	visibility: hidden;
-	transition: opacity 0.5s;
 }
 
 .source .sidebar.expanded {
@@ -1677,12 +1676,6 @@ details.rustdoc-toggle[open] > summary.hideme::after {
 		display: none;
 	}
 
-	/* It doesn't render well on mobile because of the layout, so better only have the transition
-	on desktop. */
-	.rustdoc.source .sidebar {
-		transition: width .5s;
-	}
-
 	.source .sidebar.expanded {
 		width: 300px;
 	}
diff --git a/src/test/rustdoc-gui/code-sidebar-toggle.goml b/src/test/rustdoc-gui/code-sidebar-toggle.goml
index 1818f0dbcdf41..867db056948b6 100644
--- a/src/test/rustdoc-gui/code-sidebar-toggle.goml
+++ b/src/test/rustdoc-gui/code-sidebar-toggle.goml
@@ -3,6 +3,5 @@ goto: file://|DOC_PATH|/test_docs/index.html
 click: ".srclink"
 wait-for: "#sidebar-toggle"
 click: "#sidebar-toggle"
-wait-for: 500
 fail: true
 assert-css: ("#source-sidebar", { "left": "-300px" })