diff --git a/src/librustdoc/html/render/mod.rs b/src/librustdoc/html/render/mod.rs
index 7f3e5d15de192..a79b3e8ed084b 100644
--- a/src/librustdoc/html/render/mod.rs
+++ b/src/librustdoc/html/render/mod.rs
@@ -422,6 +422,12 @@ fn settings(root_path: &str, suffix: &str, theme_names: Vec<String>) -> Result<S
             "Theme preferences",
             vec![
                 Setting::from(("use-system-theme", "Use system theme", true)),
+                Setting::Select {
+                    js_data_name: "theme",
+                    description: "Theme",
+                    default_value: "light",
+                    options: theme_names.clone(),
+                },
                 Setting::Select {
                     js_data_name: "preferred-dark-theme",
                     description: "Preferred dark theme",
diff --git a/src/librustdoc/html/static/css/rustdoc.css b/src/librustdoc/html/static/css/rustdoc.css
index 7cc0e74a79bcb..ed98c0843af26 100644
--- a/src/librustdoc/html/static/css/rustdoc.css
+++ b/src/librustdoc/html/static/css/rustdoc.css
@@ -1766,6 +1766,12 @@ details.rustdoc-toggle[open] > summary.hideme::after {
 		padding-top: 0px;
 	}
 
+	/* Space is at a premium on mobile, so remove the theme-picker icon. */
+	#theme-picker {
+		display: none;
+		width: 0;
+	}
+
 	.rustdoc {
 		flex-direction: column;
 	}
@@ -1884,12 +1890,6 @@ details.rustdoc-toggle[open] > summary.hideme::after {
 		height: 100%;
 	}
 
-	nav.sub {
-		width: calc(100% - 32px);
-		margin-left: 32px;
-		margin-bottom: 10px;
-	}
-
 	.source nav:not(.sidebar).sub {
 		margin-left: 32px;
 	}
@@ -2086,11 +2086,6 @@ details.rustdoc-toggle[open] > summary.hideme::after {
 		border: 0;
 	}
 
-	#crate-search + .search-input {
-		width: calc(100% + 71px);
-		margin-left: -36px;
-	}
-
 	#theme-picker, #settings-menu {
 		padding: 5px;
 		width: 31px;
diff --git a/src/librustdoc/html/static/js/main.js b/src/librustdoc/html/static/js/main.js
index f41c1bd817ab2..011e60b8fa0d2 100644
--- a/src/librustdoc/html/static/js/main.js
+++ b/src/librustdoc/html/static/js/main.js
@@ -129,10 +129,15 @@ function hideThemeButtonState() {
 
 // Set up the theme picker list.
 (function () {
+    if (!document.location.href.startsWith("file:///")) {
+        return;
+    }
     var themeChoices = getThemesElement();
     var themePicker = getThemePickerElement();
     var availableThemes = getVar("themes").split(",");
 
+    removeClass(themeChoices.parentElement, "hidden");
+
     function switchThemeButtonState() {
         if (themeChoices.style.display === "block") {
             hideThemeButtonState();
diff --git a/src/librustdoc/html/static/js/settings.js b/src/librustdoc/html/static/js/settings.js
index 4f10e14e8558c..e5c7e1ea1a03c 100644
--- a/src/librustdoc/html/static/js/settings.js
+++ b/src/librustdoc/html/static/js/settings.js
@@ -1,15 +1,18 @@
 // Local js definitions:
 /* global getSettingValue, getVirtualKey, onEachLazy, updateLocalStorage, updateSystemTheme */
+/* global addClass, removeClass */
 
 (function () {
     function changeSetting(settingName, value) {
         updateLocalStorage("rustdoc-" + settingName, value);
 
         switch (settingName) {
+            case "theme":
             case "preferred-dark-theme":
             case "preferred-light-theme":
             case "use-system-theme":
                 updateSystemTheme();
+                updateLightAndDark();
                 break;
         }
     }
@@ -29,7 +32,32 @@
         }
     }
 
+    function showLightAndDark() {
+        addClass(document.getElementById("theme").parentElement.parentElement, "hidden");
+        removeClass(document.getElementById("preferred-light-theme").parentElement.parentElement,
+            "hidden");
+        removeClass(document.getElementById("preferred-dark-theme").parentElement.parentElement,
+            "hidden");
+    }
+
+    function hideLightAndDark() {
+        addClass(document.getElementById("preferred-light-theme").parentElement.parentElement,
+            "hidden");
+        addClass(document.getElementById("preferred-dark-theme").parentElement.parentElement,
+            "hidden");
+        removeClass(document.getElementById("theme").parentElement.parentElement, "hidden");
+    }
+
+    function updateLightAndDark() {
+        if (getSettingValue("use-system-theme") !== "false") {
+            showLightAndDark();
+        } else {
+            hideLightAndDark();
+        }
+    }
+
     function setEvents() {
+        updateLightAndDark();
         onEachLazy(document.getElementsByClassName("slider"), function(elem) {
             var toggle = elem.previousElementSibling;
             var settingId = toggle.id;
diff --git a/src/librustdoc/html/static/js/storage.js b/src/librustdoc/html/static/js/storage.js
index d8b3ba92dcba2..2394df4c715d4 100644
--- a/src/librustdoc/html/static/js/storage.js
+++ b/src/librustdoc/html/static/js/storage.js
@@ -187,22 +187,25 @@ var updateSystemTheme = (function() {
     var mql = window.matchMedia("(prefers-color-scheme: dark)");
 
     function handlePreferenceChange(mql) {
+        let use = function(theme) {
+            switchTheme(window.currentTheme, window.mainTheme, theme, true);
+        };
         // maybe the user has disabled the setting in the meantime!
         if (getSettingValue("use-system-theme") !== "false") {
             var lightTheme = getSettingValue("preferred-light-theme") || "light";
             var darkTheme = getSettingValue("preferred-dark-theme") || "dark";
 
             if (mql.matches) {
-                // prefers a dark theme
-                switchTheme(window.currentTheme, window.mainTheme, darkTheme, true);
+                use(darkTheme);
             } else {
                 // prefers a light theme, or has no preference
-                switchTheme(window.currentTheme, window.mainTheme, lightTheme, true);
+                use(lightTheme);
             }
-
             // note: we save the theme so that it doesn't suddenly change when
             // the user disables "use-system-theme" and reloads the page or
             // navigates to another page
+        } else {
+            use(getSettingValue("theme"));
         }
     }
 
diff --git a/src/librustdoc/templates/page.html b/src/librustdoc/templates/page.html
index 02808754b539b..1ef001ec2b719 100644
--- a/src/librustdoc/templates/page.html
+++ b/src/librustdoc/templates/page.html
@@ -96,7 +96,7 @@
                     {%- endif -%}
                 </a> {#- -#}
                 <nav class="sub"> {#- -#}
-                    <div class="theme-picker"> {#- -#}
+                    <div class="theme-picker hidden"> {#- -#}
                         <button id="theme-picker" aria-label="Pick another theme!" aria-haspopup="menu" title="themes"> {#- -#}
                             <img width="18" height="18" alt="Pick another theme!" {# -#}
                              src="{{static_root_path|safe}}brush{{page.resource_suffix}}.svg"> {#- -#}
diff --git a/src/test/rustdoc-gui/toggle-docs-mobile.goml b/src/test/rustdoc-gui/toggle-docs-mobile.goml
index 6e0ad8e0fa7fb..67b9164cfec71 100644
--- a/src/test/rustdoc-gui/toggle-docs-mobile.goml
+++ b/src/test/rustdoc-gui/toggle-docs-mobile.goml
@@ -1,12 +1,12 @@
 goto: file://|DOC_PATH|/test_docs/struct.Foo.html
 size: (433, 600)
 assert-attribute: (".top-doc", {"open": ""})
-click: (4, 240) // This is the position of the top doc comment toggle
+click: (4, 260) // This is the position of the top doc comment toggle
 assert-attribute-false: (".top-doc", {"open": ""})
-click: (4, 240)
+click: (4, 260)
 assert-attribute: (".top-doc", {"open": ""})
 // To ensure that the toggle isn't over the text, we check that the toggle isn't clicked.
-click: (3, 240)
+click: (3, 260)
 assert-attribute: (".top-doc", {"open": ""})
 
 // Assert the position of the toggle on the top doc block.
@@ -22,10 +22,10 @@ assert-position: (
 // Now we do the same but with a little bigger width
 size: (600, 600)
 assert-attribute: (".top-doc", {"open": ""})
-click: (4, 240) // New Y position since all search elements are back on one line.
+click: (4, 260) // New Y position since all search elements are back on one line.
 assert-attribute-false: (".top-doc", {"open": ""})
-click: (4, 240)
+click: (4, 260)
 assert-attribute: (".top-doc", {"open": ""})
 // To ensure that the toggle isn't over the text, we check that the toggle isn't clicked.
-click: (3, 240)
+click: (3, 260)
 assert-attribute: (".top-doc", {"open": ""})