Customize: Introduce a new experience for discovering, installing, and previewing themes within the customizer.

Unify the theme-browsing and theme-customization experiences by introducing a comprehensive theme browser and installer directly accessible in the customizer. Replaces the customizer theme switcher with a full-screen panel for discovering/browsing and installing themes available on WordPress.org. Themes can now be installed and previewed directly in the customizer without entering the wp-admin context.

For details, see https://make.wordpress.org/core/2016/10/03/feature-proposal-a-new-experience-for-discovering-installing-and-previewing-themes-in-the-customizer/

Fixes #37661, #34843.
Props celloexpressions, folletto, westonruter, karmatosed, afercia.

Built from https://develop.svn.wordpress.org/trunk@38813


git-svn-id: http://core.svn.wordpress.org/trunk@38756 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/css/customize-controls-rtl.css

@@ -271,21 +271,17 @@ body {
 }
 
 #customize-theme-controls .customize-pane-child.open,
-#customize-theme-controls .customize-pane-child.current-panel,
+#customize-theme-controls .customize-pane-child.current-panel {
-#customize-theme-controls .customize-themes-panel.customize-pane-child.current-panel {
 	-webkit-transform: none;
 	-ms-transform: none;
 	transform: none;
 }
 
-#customize-theme-controls .customize-themes-panel.customize-pane-child,
 .section-open #customize-theme-controls .customize-pane-parent,
 .in-sub-panel #customize-theme-controls .customize-pane-parent,
 .section-open #customize-info,
 .in-sub-panel #customize-info,
-.in-sub-panel.section-open #customize-theme-controls .customize-pane-child.current-panel,
+.in-sub-panel.section-open #customize-theme-controls .customize-pane-child.current-panel {
-.in-themes-panel #customize-theme-controls .customize-pane-parent,
-.in-themes-panel #customize-info {
 	visibility: hidden;
 	height: 0;
 	overflow: hidden;
@@ -296,10 +292,8 @@ body {
 
 .section-open #customize-theme-controls .customize-pane-parent.busy,
 .in-sub-panel #customize-theme-controls .customize-pane-parent.busy,
-.in-themes-panel #customize-theme-controls .customize-pane-parent.busy,
 .section-open #customize-info.busy,
 .in-sub-panel #customize-info.busy,
-.in-themes-panel #customize-info.busy,
 .busy.section-open.in-sub-panel #customize-theme-controls .customize-pane-child.current-panel,
 #customize-theme-controls .customize-pane-child.open,
 #customize-theme-controls .customize-pane-child.current-panel,
@@ -309,13 +303,6 @@ body {
 	overflow: auto;
 }
 
-.in-themes-panel #customize-theme-controls .customize-pane-parent,
-.in-themes-panel #customize-info {
-	-webkit-transform: translateX(-100%);
-	-ms-transform: translateX(-100%);
-	transform: translateX(-100%);
-}
-
 #customize-theme-controls .customize-pane-child.accordion-section-content,
 #customize-theme-controls .customize-pane-child.accordion-sub-container {
 	display: block;
@@ -406,7 +393,7 @@ h3.customize-section-title {
 	display: block;
 	float: right;
 	width: 48px;
-	height: 71px;
+	height: 70px;
 	padding: 0 0 0 24px;
 	margin: 0;
 	background: #fff;
@@ -420,7 +407,7 @@ h3.customize-section-title {
 }
 
 .customize-section-back {
-	height: 74px;
+	height: 73px;
 }
 
 .ios .customize-panel-back {
@@ -996,15 +983,21 @@ p.customize-section-description {
 	animation: customize-reload .75s;
 }
 
-#customize-theme-controls .control-section-themes .accordion-section-title:hover, /* Not a focusable element. */
+#customize-theme-controls .control-panel-themes {
-#customize-theme-controls .control-section-themes .accordion-section-title {
+	border-bottom: none;
+}
+
+#customize-theme-controls .control-panel-themes > .accordion-section-title:hover, /* Not a focusable element. */
+#customize-theme-controls .control-panel-themes > .accordion-section-title {
 	cursor: default;
 	background: #fff;
 	color: #555;
 	border-top: 1px solid #ddd;
 	border-bottom: 1px solid #ddd;
 	border-right: none;
-	margin-top: 0;
+	border-left: none;
+	margin: 0 0 15px 0;
+	padding-left: 100px; /* Space for the button */
 }
 
 #customize-theme-controls .control-section-themes .customize-themes-panel .accordion-section-title:first-child:hover, /* Not a focusable element. */
@@ -1012,29 +1005,14 @@ p.customize-section-description {
 	border-top: 0;
 }
 
-#customize-theme-controls .control-section-themes > .accordion-section-title:hover, /* Not a focusable element. */
+.control-panel-themes .accordion-section-title span.customize-action,
-#customize-theme-controls .control-section-themes > .accordion-section-title {
-	margin: 0 0 15px;
-}
-
-#customize-controls .customize-themes-panel .accordion-section-title {
-	margin: 15px -8px;
-}
-
-#customize-controls .control-section-themes .accordion-section-title,
-#customize-controls .customize-themes-panel .accordion-section-title {
-	padding-left: 100px; /* Space for the button */
-}
-
-#customize-controls .control-section-themes .accordion-section-title span.customize-action,
 #customize-controls .customize-section-title span.customize-action {
 	font-size: 13px;
 	display: block;
 	font-weight: 400;
 }
 
-#customize-controls .control-section-themes .accordion-section-title .change-theme,
+.control-panel-themes .accordion-section-title .change-theme {
-#customize-controls .customize-themes-panel .accordion-section-title .customize-theme {
 	position: absolute;
 	left: 10px;
 	top: 50%;
@@ -1042,38 +1020,363 @@ p.customize-section-description {
 	font-weight: 400;
 }
 
-#customize-controls .control-section-themes .accordion-section-title:before {
+#customize-theme-controls .control-panel-themes > .accordion-section-title:after {
 	display: none;
 }
 
-#customize-controls .customize-themes-panel {
+.control-panel-themes .customize-themes-full-container {
-	padding: 0 8px;
+	position: fixed;
-	background: #f1f1f1;
+	top: 0;
-	-webkit-box-sizing: border-box;
+	right: 0;
-	-moz-box-sizing: border-box;
+	transition: .18s right ease-in-out;
-	box-sizing: border-box;
+	margin: 0 300px 0 0;
+	padding:25px;
+	overflow-y: scroll;
+	width: calc(100% - 350px);
+	height: calc(100% - 50px);
+	background: #eee;
+	z-index: 20;
 }
 
-#customize-controls .customize-themes-panel .accordion-section-title:first-child {
+/* Animations for opening the themes panel */
-	margin-top: 0;
+#customize-header-actions .save,
+#customize-header-actions .spinner,
+#customize-header-actions .customize-controls-preview-toggle {
+	position: relative;
+	top: 0;
+	transition: .18s top ease-in-out;
 }
 
-#customize-controls .customize-themes-panel .accordion-section-title:nth-child(2) {
+#customize-footer-actions,
+#customize-footer-actions .collapse-sidebar {
+	bottom: 0;
+	transition: .18s bottom ease-in-out;
+}
+
+.in-themes-panel:not(.animating) #customize-header-actions .save,
+.in-themes-panel:not(.animating) #customize-header-actions .spinner,
+.in-themes-panel:not(.animating) #customize-header-actions .customize-controls-preview-toggle,
+.in-themes-panel:not(.animating) #customize-preview,
+.in-themes-panel:not(.animating) #customize-footer-actions {
+	visibility: hidden;
+}
+
+.wp-full-overlay.in-themes-panel {
+	background: #eee; /* Prevents a black flash when fading in the panel */
+}
+
+.in-themes-panel #customize-header-actions .save,
+.in-themes-panel #customize-header-actions .spinner,
+.in-themes-panel #customize-header-actions .customize-controls-preview-toggle {
+	top: -45px;
+}
+
+.in-themes-panel #customize-footer-actions,
+.in-themes-panel #customize-footer-actions .collapse-sidebar {
+	bottom: -45px;
+}
+
+/* Don't show the theme count while the panel opens, as it's in the wrong place during the animation */
+.in-themes-panel.animating .control-panel-themes .filter-themes-count {
+	display: none;
+}
+
+.in-themes-panel.wp-full-overlay .wp-full-overlay-sidebar-content {
+	bottom: 0;
+}
+
+/* Adds a delay before fading in to avoid it "jumping" */
+@keyframes themes-fade-in {
+	0% {
+		opacity: 0;
+	}
+	50% {
+		opacity: 0;
+	}
+	100% {
+		opacity: 1;
+	}
+}
+
+.control-panel-themes .customize-themes-full-container.animate {
+	animation: .6s themes-fade-in 1;
+}
+
+.in-themes-panel:not(.animating) .control-panel-themes .filter-themes-count {
+	animation: .6s themes-fade-in 1;
+}
+
+.control-panel-themes .filter-themes-count {
+	position: fixed;
+	top: 0;
+	right: 48px;
+	width: 222px;
+	padding: 6px 15px;
+	margin: 0;
+	line-height: 32px;
+	text-align: left;
+	z-index: 10;
+}
+
+.control-panel-themes .filter-themes-count .themes-displayed {
+	font-weight: 600;
+	color: #555d66;
+}
+
+.control-panel-themes .filter-themes-count .see-themes,
+.control-panel-themes .filter-themes-count .filter-themes {
+	display: none;
+}
+
+
+/* Mobile - toggle between themes and filters */
+@media screen and (max-width:600px) {
+
+	/* Show a spinner in the filters view also, reusing the main customize spinner */
+	.in-themes-panel.loading #customize-header-actions .spinner {
+		position: fixed;
+		top: 0;
+		right: 48px;
+		visibility: visible;
+	}
+
+	.in-themes-panel.loading.showing-themes #customize-header-actions .spinner {
+		visibility: hidden;
+	}
+
+	.control-panel-themes .filter-themes-count {
+		width: calc(100% - 93px);
+	}
+
+	.control-panel-themes .filter-themes-count .themes-displayed {
+		display: none;
+	}
+
+	.wp-full-overlay:not(.showing-themes) .control-panel-themes .filter-themes-count .see-themes {
+		display: block;
+		float: left;
+	}
+
+	.wp-full-overlay.showing-themes .control-panel-themes .filter-themes-count .filter-themes {
+		display: block;
+		float: left;
+	}
+
+	.in-themes-panel.showing-themes .control-panel-themes .customize-panel-back {
+		position: fixed;
+		top: 0;
+		right: 0;
+		z-index: 10;
+		height: 45px;
+		background: #eee;
+	}
+
+	.in-themes-panel.showing-themes .control-panel-themes .customize-panel-back:before {
+		line-height: 45px;
+	}
+
+	.control-panel-themes .customize-themes-full-container {
+		width: calc(100% - 50px);
+		margin: 0;
+		top: 46px;
+		height: calc(100% - 96px);
+		z-index: 1;
+		display: none;
+	}
+
+	.showing-themes .control-panel-themes .customize-themes-full-container {
+		display: block;
+	}
+}
+
+.control-panel-themes .customize-themes-notifications .notice {
+	margin: 0 0 25px 0;
+}
+
+.customize-themes-full-container .customize-themes-section {
+	display: none !important; /* There is unknown JS that perpetually tries to show all theme sections when more items are added. */
+	overflow: hidden;
+}
+
+.customize-themes-full-container .customize-themes-section.current-section {
+	display: list-item !important; /* There is unknown JS that perpetually tries to show all theme sections when more items are added. */
+}
+
+.theme-section .customize-themes-text-before {
+	padding: 0 15px 8px 0;
+	margin: 15px 0 0 0;
+	line-height: 16px;
+	border-bottom: 1px solid #ddd;
+	color: #555d66;
+}
+
+.control-panel-themes .customize-themes-section-title {
+	width: 100%;
+	background: #fff;
+	box-shadow: none;
+	outline: none;
+	border-top: none;
+	border-bottom: 1px solid #ddd;
+	border-right: 4px solid #fff;
+	border-left: none;
+	cursor: pointer;
+	padding: 10px 15px;
+	position: relative;
+	text-align: right;
 	font-size: 14px;
 	font-weight: 600;
+	color: #555d66;
+	text-shadow: none;
+}
+
+.control-panel-themes .theme-section {
+	margin: 0;
+	position: relative;
+}
+
+.control-panel-themes .customize-themes-section-title:focus,
+.control-panel-themes .customize-themes-section-title:hover {
+	border-right-color: #0073aa;
+	color: #0073aa;
+	background: #f5f5f5;
+}
+
+.control-panel-themes .theme-section .customize-themes-section-title.selected:after {
+	content: "\f147";
+	font: 16px/1 dashicons;
+	box-sizing: border-box;
+	width: 20px;
+	height: 20px;
+	padding: 3px 1px 1px 3px; /* Re-align the icon to the smaller grid */
+	border-radius: 100%;
+	position: absolute;
+	top: 9px;
+	left: 15px;
+	background: #0073aa;
+	color: #fff;
+}
+
+.control-panel-themes .customize-themes-section-title.selected {
+	color: #0073aa;
+}
+
+.control-panel-themes .customize-themes-section-title.themes-section-search_themes {
+	border-right: none;
+	padding: 5px 15px 5px 10px;
+	width: auto;
+}
+
+.control-panel-themes .customize-themes-section-title.themes-section-feature_filter_themes:after,
+.control-panel-themes .customize-themes-section-title.themes-section-favorites_themes:after {
+	content: "\f140";
+	font: 20px/1 dashicons;
+	position: absolute;
+	left: 15px;
+	top: 8px;
+}
+
+.control-panel-themes .customize-themes-section-title.themes-section-search_themes .wp-filter-search {
+	width: 100%;
+}
+
+.control-panel-themes .customize-themes-section-title.themes-section-search_themes.selected,
+.control-panel-themes .customize-themes-section-title.themes-section-search_themes:hover {
+	background: #fff;
+	cursor: default;
+}
+
+.control-panel-themes .customize-themes-section-title.themes-section-feature_filter_themes {
+	margin-top: 15px;
+	border-top: 1px solid #ddd;
+}
+
+.control-panel-themes .filter-details {
+	background: #f5f5f5;
+	margin: 0;
+	padding: 8px 15px;
+	border-top: none;
+	border-bottom: 1px solid #ddd;
+	display: none;
+}
+
+.control-panel-themes .customize-themes-section-title.selected.details-open {
+	border-bottom-color: #f5f5f5;
+    border-right-color: #f5f5f5;
+	background: #f5f5f5;
+}
+
+.control-panel-themes .favorites-form.filter-details label {
+	padding-bottom: 6px;
+	display: inline-block;
+}
+
+.control-panel-themes .filter-details .filter-group {
+	float: none;
+	width: 100%;
+	background: transparent;
+	border: none;
+	padding: 0;
+	box-shadow: none;
+}
+
+.control-panel-themes .filter-details .filter-group legend button {
+	padding: 18px 10px 8px 15px;
+	line-height: 14px;
+	border-bottom: 1px solid #ddd;
+	width: 100%;
+	text-align: right;
+}
+
+.control-panel-themes .filter-details .filter-group legend {
+	position: relative;
+	top: 0;
+	width: 100%;
+}
+
+.control-panel-themes .filter-details .filter-group legend button:after {
+	content: "\f140";
+	font: 20px/1 dashicons;
+	position: absolute;
+	bottom: 6px;
+	left: 5px;
+}
+
+.control-panel-themes .filter-details .filter-group legend button:hover,
+.control-panel-themes .filter-details .filter-group legend button:focus {
+	color: #0073aa;
+	border-bottom-color: #0073aa; /* Color change for focus style should be acceptable because border-bottom is barely visible previously. */
+	outline: none;
+	box-shadow: none;
+}
+
+.control-panel-themes .filter-details .filter-group legend button.open:after {
+	content: "\f142";
+}
+
+.control-panel-themes .filter-details .filter-group .filter-group-feature {
+	display: none;
+	margin: 0;
+}
+
+.control-panel-themes .filter-details .filter-group-feature label {
+	border: 1px solid #ddd;
+	border-top: 0;
+	background: #fff;
+	color: #555d66;
+	margin: 0;
+	padding: 12px 34px 12px 10px;
+	width: calc(100% - 46px);
+	line-height: 16px;
+	font-weight: 600;
 }
 
-#customize-controls .customize-themes-panel > h2 {
+.control-panel-themes .filter-details .filter-group-feature input {
-	padding: 15px 8px 0 8px;
+	position: absolute;
+	margin: 12px 10px;
 }
 
-#customize-theme-controls .customize-themes-panel .accordion-section-content {
+.control-panel-themes .filter-details .filter-group-feature label:hover {
-	background: transparent;
+	color: #0073aa;
-	display: block;
-}
-
-.customize-control.customize-control-theme {
-	margin-bottom: 8px;
 }
 
 #customize-theme-controls .themes.accordion-section-content {
@@ -1083,17 +1386,108 @@ p.customize-section-description {
 	width: 100%;
 }
 
+.loading .customize-themes-section .spinner {
+	display: block;
+	visibility: visible;
+	position: relative;
+	clear: both;
+	width: 20px;
+	height: 20px;
+	right: calc(50% - 10px);
+	float: none;
+	margin-top: 50px;
+}
+
+.customize-themes-section .filter-drawer {
+	border-top: none;
+	display: block;
+	background: transparent;
+	padding-top: 5px;
+}
+
+.customize-themes-section .clear-filters {
+	margin-right: 8px;
+	display: none;
+}
+
+.customize-themes-section .no-themes {
+	display: none;
+}
+
+.themes-section-installed_themes .theme .notice-success {
+	display: none; /* Hide "installed" notice on installed themes tab. */
+}
+
+.control-panel-themes .theme-browser .theme .theme-actions .button-primary {
+	margin: 0 8px 0 0;
+}
+
+.customize-control-theme .theme {
+	width: 100%;
+	margin: 0;
+}
+
+.customize-control.customize-control-theme { /* override most properties on .customize-control */
+	box-sizing: border-box;
+	width: 18.4%;
+	margin: 0 0 2% 2%;
+	padding: 0;
+	clear: none;
+}
+
+/* 5 columns above 2100px */
+@media screen and (min-width: 2101px) {
+	.customize-control.customize-control-theme:nth-child(5n) {
+		margin-left: 0;
+	}
+}
+
+/* 4 columns up to 2100px */
+@media screen and (min-width: 1601px) and (max-width: 2100px) {
+	.customize-control.customize-control-theme {
+		width: 23.5%;
+	}
+
+	.customize-control.customize-control-theme:nth-child(4n) {
+		margin-left: 0;
+	}
+}
+
+/* 3 columns up to 1600px */
+@media screen and (min-width: 1201px) and (max-width: 1600px) {
+	.customize-control.customize-control-theme {
+		width: 32%;
+	}
+
+	.customize-control.customize-control-theme:nth-child(3n) {
+		margin-left: 0;
+	}
+}
+
+/* 2 columns up to 1200px */
+@media screen and (min-width: 851px) and (max-width: 1200px) {
+	.customize-control.customize-control-theme {
+		width: 49%;
+	}
+
+	.customize-control.customize-control-theme:nth-child(even) {
+		margin-left: 0;
+	}
+}
+
+/* 1 column up to 850 px */
+@media screen and (max-width: 850px) {
+	.customize-control.customize-control-theme {
+		width: 100%;
+		margin: 0 0 3% 0;
+	}
+}
+
 .wp-customizer .theme-browser .themes {
 	padding-bottom: 8px;
 }
 
-.wp-customizer .theme-browser .theme {
-	margin: 0;
-	width: 100%;
-}
-
 .wp-customizer .theme-browser .theme .theme-actions {
-	-ms-filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=100)";
 	opacity: 1;
 }
 
@@ -1112,15 +1506,6 @@ p.customize-section-description {
 	width: 100%;
 }
 
-.control-section-themes .accordion-section-title:after,
-.customize-themes-panel .accordion-section-title:after {
-	display: none;
-}
-
-.customize-themes-panel.control-panel-content {
-	border-top: 1px solid #ddd;
-}
-
 /* Details View */
 .wp-customizer .theme-overlay {
 	display: none;
@@ -1135,31 +1520,58 @@ p.customize-section-description {
 	z-index: 109;
 }
 
+/* Avoid a z-index war by resetting elements that should be under the overlay.
+   This is likely required because of the way that sections and panels are positioned. */
+.wp-customizer.modal-open #customize-header-actions,
+.wp-customizer.modal-open .control-panel-themes .filter-themes-count,
+.wp-customizer.modal-open .control-panel-themes .customize-themes-section-title.selected:after {
+	z-index: -1;
+}
+
 .wp-customizer .theme-overlay .theme-backdrop {
 	background: rgba( 238, 238, 238, 0.75 );
 	position: fixed;
 	z-index: 110;
 }
 
+.wp-customizer .theme-overlay .star-rating {
+	float: right;
+	margin-left: 8px;
+}
+
+.wp-customizer .theme-rating .num-ratings {
+	line-height: 20px;
+}
+
 .wp-customizer .theme-overlay .theme-wrap {
 	right: 90px;
 	left: 90px;
 	top: 45px;
 	bottom: 45px;
 	z-index: 120;
-	max-width: 1740px; /* To ensure that theme screenshots are not displayed larger than 880px wide. */
 }
 
 .wp-customizer .theme-overlay .theme-actions {
-	text-align: left; /* Because there's only one action, match the pattern of media modals and right-align the action. */
+	text-align: left; /* Because there're only one or two actions, match the UI pattern of media modals and right-align the action. */
+	padding: 10px 15px;
 }
 
-.ie8 .wp-customizer .theme-overlay .theme-header,
+.wp-customizer .theme-overlay .theme-actions .theme-install.preview {
-.ie8 .wp-customizer .theme-overlay .theme-about,
+	margin-right: 8px;
-.ie8 .wp-customizer .theme-overlay .theme-actions {
-	position: static;
 }
 
+.control-panel-themes .theme-actions .delete-theme {
+	right: 15px; /* these override themes.css on mobile */
+	left: auto;
+	bottom: auto;
+	position: absolute;
+}
+
+.modal-open .in-themes-panel #customize-controls .wp-full-overlay-sidebar-content {
+	overflow: visible; /* Prevent the top-level Customizer controls from becoming visible when elements on the right of the details modal are focused. */
+}
+
+
 /* Small Screens */
 @media (max-width:850px), (max-height:472px) {
 	.wp-customizer .theme-overlay .theme-wrap {

wp-admin/css/customize-controls.css

@@ -271,21 +271,17 @@ body {
 }
 
 #customize-theme-controls .customize-pane-child.open,
-#customize-theme-controls .customize-pane-child.current-panel,
+#customize-theme-controls .customize-pane-child.current-panel {
-#customize-theme-controls .customize-themes-panel.customize-pane-child.current-panel {
 	-webkit-transform: none;
 	-ms-transform: none;
 	transform: none;
 }
 
-#customize-theme-controls .customize-themes-panel.customize-pane-child,
 .section-open #customize-theme-controls .customize-pane-parent,
 .in-sub-panel #customize-theme-controls .customize-pane-parent,
 .section-open #customize-info,
 .in-sub-panel #customize-info,
-.in-sub-panel.section-open #customize-theme-controls .customize-pane-child.current-panel,
+.in-sub-panel.section-open #customize-theme-controls .customize-pane-child.current-panel {
-.in-themes-panel #customize-theme-controls .customize-pane-parent,
-.in-themes-panel #customize-info {
 	visibility: hidden;
 	height: 0;
 	overflow: hidden;
@@ -296,10 +292,8 @@ body {
 
 .section-open #customize-theme-controls .customize-pane-parent.busy,
 .in-sub-panel #customize-theme-controls .customize-pane-parent.busy,
-.in-themes-panel #customize-theme-controls .customize-pane-parent.busy,
 .section-open #customize-info.busy,
 .in-sub-panel #customize-info.busy,
-.in-themes-panel #customize-info.busy,
 .busy.section-open.in-sub-panel #customize-theme-controls .customize-pane-child.current-panel,
 #customize-theme-controls .customize-pane-child.open,
 #customize-theme-controls .customize-pane-child.current-panel,
@@ -309,13 +303,6 @@ body {
 	overflow: auto;
 }
 
-.in-themes-panel #customize-theme-controls .customize-pane-parent,
-.in-themes-panel #customize-info {
-	-webkit-transform: translateX(100%);
-	-ms-transform: translateX(100%);
-	transform: translateX(100%);
-}
-
 #customize-theme-controls .customize-pane-child.accordion-section-content,
 #customize-theme-controls .customize-pane-child.accordion-sub-container {
 	display: block;
@@ -406,7 +393,7 @@ h3.customize-section-title {
 	display: block;
 	float: left;
 	width: 48px;
-	height: 71px;
+	height: 70px;
 	padding: 0 24px 0 0;
 	margin: 0;
 	background: #fff;
@@ -420,7 +407,7 @@ h3.customize-section-title {
 }
 
 .customize-section-back {
-	height: 74px;
+	height: 73px;
 }
 
 .ios .customize-panel-back {
@@ -996,15 +983,21 @@ p.customize-section-description {
 	animation: customize-reload .75s;
 }
 
-#customize-theme-controls .control-section-themes .accordion-section-title:hover, /* Not a focusable element. */
+#customize-theme-controls .control-panel-themes {
-#customize-theme-controls .control-section-themes .accordion-section-title {
+	border-bottom: none;
+}
+
+#customize-theme-controls .control-panel-themes > .accordion-section-title:hover, /* Not a focusable element. */
+#customize-theme-controls .control-panel-themes > .accordion-section-title {
 	cursor: default;
 	background: #fff;
 	color: #555;
 	border-top: 1px solid #ddd;
 	border-bottom: 1px solid #ddd;
 	border-left: none;
-	margin-top: 0;
+	border-right: none;
+	margin: 0 0 15px 0;
+	padding-right: 100px; /* Space for the button */
 }
 
 #customize-theme-controls .control-section-themes .customize-themes-panel .accordion-section-title:first-child:hover, /* Not a focusable element. */
@@ -1012,29 +1005,14 @@ p.customize-section-description {
 	border-top: 0;
 }
 
-#customize-theme-controls .control-section-themes > .accordion-section-title:hover, /* Not a focusable element. */
+.control-panel-themes .accordion-section-title span.customize-action,
-#customize-theme-controls .control-section-themes > .accordion-section-title {
-	margin: 0 0 15px;
-}
-
-#customize-controls .customize-themes-panel .accordion-section-title {
-	margin: 15px -8px;
-}
-
-#customize-controls .control-section-themes .accordion-section-title,
-#customize-controls .customize-themes-panel .accordion-section-title {
-	padding-right: 100px; /* Space for the button */
-}
-
-#customize-controls .control-section-themes .accordion-section-title span.customize-action,
 #customize-controls .customize-section-title span.customize-action {
 	font-size: 13px;
 	display: block;
 	font-weight: 400;
 }
 
-#customize-controls .control-section-themes .accordion-section-title .change-theme,
+.control-panel-themes .accordion-section-title .change-theme {
-#customize-controls .customize-themes-panel .accordion-section-title .customize-theme {
 	position: absolute;
 	right: 10px;
 	top: 50%;
@@ -1042,38 +1020,363 @@ p.customize-section-description {
 	font-weight: 400;
 }
 
-#customize-controls .control-section-themes .accordion-section-title:before {
+#customize-theme-controls .control-panel-themes > .accordion-section-title:after {
 	display: none;
 }
 
-#customize-controls .customize-themes-panel {
+.control-panel-themes .customize-themes-full-container {
-	padding: 0 8px;
+	position: fixed;
-	background: #f1f1f1;
+	top: 0;
-	-webkit-box-sizing: border-box;
+	left: 0;
-	-moz-box-sizing: border-box;
+	transition: .18s left ease-in-out;
-	box-sizing: border-box;
+	margin: 0 0 0 300px;
+	padding:25px;
+	overflow-y: scroll;
+	width: calc(100% - 350px);
+	height: calc(100% - 50px);
+	background: #eee;
+	z-index: 20;
 }
 
-#customize-controls .customize-themes-panel .accordion-section-title:first-child {
+/* Animations for opening the themes panel */
-	margin-top: 0;
+#customize-header-actions .save,
+#customize-header-actions .spinner,
+#customize-header-actions .customize-controls-preview-toggle {
+	position: relative;
+	top: 0;
+	transition: .18s top ease-in-out;
 }
 
-#customize-controls .customize-themes-panel .accordion-section-title:nth-child(2) {
+#customize-footer-actions,
+#customize-footer-actions .collapse-sidebar {
+	bottom: 0;
+	transition: .18s bottom ease-in-out;
+}
+
+.in-themes-panel:not(.animating) #customize-header-actions .save,
+.in-themes-panel:not(.animating) #customize-header-actions .spinner,
+.in-themes-panel:not(.animating) #customize-header-actions .customize-controls-preview-toggle,
+.in-themes-panel:not(.animating) #customize-preview,
+.in-themes-panel:not(.animating) #customize-footer-actions {
+	visibility: hidden;
+}
+
+.wp-full-overlay.in-themes-panel {
+	background: #eee; /* Prevents a black flash when fading in the panel */
+}
+
+.in-themes-panel #customize-header-actions .save,
+.in-themes-panel #customize-header-actions .spinner,
+.in-themes-panel #customize-header-actions .customize-controls-preview-toggle {
+	top: -45px;
+}
+
+.in-themes-panel #customize-footer-actions,
+.in-themes-panel #customize-footer-actions .collapse-sidebar {
+	bottom: -45px;
+}
+
+/* Don't show the theme count while the panel opens, as it's in the wrong place during the animation */
+.in-themes-panel.animating .control-panel-themes .filter-themes-count {
+	display: none;
+}
+
+.in-themes-panel.wp-full-overlay .wp-full-overlay-sidebar-content {
+	bottom: 0;
+}
+
+/* Adds a delay before fading in to avoid it "jumping" */
+@keyframes themes-fade-in {
+	0% {
+		opacity: 0;
+	}
+	50% {
+		opacity: 0;
+	}
+	100% {
+		opacity: 1;
+	}
+}
+
+.control-panel-themes .customize-themes-full-container.animate {
+	animation: .6s themes-fade-in 1;
+}
+
+.in-themes-panel:not(.animating) .control-panel-themes .filter-themes-count {
+	animation: .6s themes-fade-in 1;
+}
+
+.control-panel-themes .filter-themes-count {
+	position: fixed;
+	top: 0;
+	left: 48px;
+	width: 222px;
+	padding: 6px 15px;
+	margin: 0;
+	line-height: 32px;
+	text-align: right;
+	z-index: 10;
+}
+
+.control-panel-themes .filter-themes-count .themes-displayed {
+	font-weight: 600;
+	color: #555d66;
+}
+
+.control-panel-themes .filter-themes-count .see-themes,
+.control-panel-themes .filter-themes-count .filter-themes {
+	display: none;
+}
+
+
+/* Mobile - toggle between themes and filters */
+@media screen and (max-width:600px) {
+
+	/* Show a spinner in the filters view also, reusing the main customize spinner */
+	.in-themes-panel.loading #customize-header-actions .spinner {
+		position: fixed;
+		top: 0;
+		left: 48px;
+		visibility: visible;
+	}
+
+	.in-themes-panel.loading.showing-themes #customize-header-actions .spinner {
+		visibility: hidden;
+	}
+
+	.control-panel-themes .filter-themes-count {
+		width: calc(100% - 93px);
+	}
+
+	.control-panel-themes .filter-themes-count .themes-displayed {
+		display: none;
+	}
+
+	.wp-full-overlay:not(.showing-themes) .control-panel-themes .filter-themes-count .see-themes {
+		display: block;
+		float: right;
+	}
+
+	.wp-full-overlay.showing-themes .control-panel-themes .filter-themes-count .filter-themes {
+		display: block;
+		float: right;
+	}
+
+	.in-themes-panel.showing-themes .control-panel-themes .customize-panel-back {
+		position: fixed;
+		top: 0;
+		left: 0;
+		z-index: 10;
+		height: 45px;
+		background: #eee;
+	}
+
+	.in-themes-panel.showing-themes .control-panel-themes .customize-panel-back:before {
+		line-height: 45px;
+	}
+
+	.control-panel-themes .customize-themes-full-container {
+		width: calc(100% - 50px);
+		margin: 0;
+		top: 46px;
+		height: calc(100% - 96px);
+		z-index: 1;
+		display: none;
+	}
+
+	.showing-themes .control-panel-themes .customize-themes-full-container {
+		display: block;
+	}
+}
+
+.control-panel-themes .customize-themes-notifications .notice {
+	margin: 0 0 25px 0;
+}
+
+.customize-themes-full-container .customize-themes-section {
+	display: none !important; /* There is unknown JS that perpetually tries to show all theme sections when more items are added. */
+	overflow: hidden;
+}
+
+.customize-themes-full-container .customize-themes-section.current-section {
+	display: list-item !important; /* There is unknown JS that perpetually tries to show all theme sections when more items are added. */
+}
+
+.theme-section .customize-themes-text-before {
+	padding: 0 0 8px 15px;
+	margin: 15px 0 0 0;
+	line-height: 16px;
+	border-bottom: 1px solid #ddd;
+	color: #555d66;
+}
+
+.control-panel-themes .customize-themes-section-title {
+	width: 100%;
+	background: #fff;
+	box-shadow: none;
+	outline: none;
+	border-top: none;
+	border-bottom: 1px solid #ddd;
+	border-left: 4px solid #fff;
+	border-right: none;
+	cursor: pointer;
+	padding: 10px 15px;
+	position: relative;
+	text-align: left;
 	font-size: 14px;
 	font-weight: 600;
+	color: #555d66;
+	text-shadow: none;
+}
+
+.control-panel-themes .theme-section {
+	margin: 0;
+	position: relative;
+}
+
+.control-panel-themes .customize-themes-section-title:focus,
+.control-panel-themes .customize-themes-section-title:hover {
+	border-left-color: #0073aa;
+	color: #0073aa;
+	background: #f5f5f5;
+}
+
+.control-panel-themes .theme-section .customize-themes-section-title.selected:after {
+	content: "\f147";
+	font: 16px/1 dashicons;
+	box-sizing: border-box;
+	width: 20px;
+	height: 20px;
+	padding: 3px 3px 1px 1px; /* Re-align the icon to the smaller grid */
+	border-radius: 100%;
+	position: absolute;
+	top: 9px;
+	right: 15px;
+	background: #0073aa;
+	color: #fff;
+}
+
+.control-panel-themes .customize-themes-section-title.selected {
+	color: #0073aa;
+}
+
+.control-panel-themes .customize-themes-section-title.themes-section-search_themes {
+	border-left: none;
+	padding: 5px 10px 5px 15px;
+	width: auto;
+}
+
+.control-panel-themes .customize-themes-section-title.themes-section-feature_filter_themes:after,
+.control-panel-themes .customize-themes-section-title.themes-section-favorites_themes:after {
+	content: "\f140";
+	font: 20px/1 dashicons;
+	position: absolute;
+	right: 15px;
+	top: 8px;
+}
+
+.control-panel-themes .customize-themes-section-title.themes-section-search_themes .wp-filter-search {
+	width: 100%;
+}
+
+.control-panel-themes .customize-themes-section-title.themes-section-search_themes.selected,
+.control-panel-themes .customize-themes-section-title.themes-section-search_themes:hover {
+	background: #fff;
+	cursor: default;
+}
+
+.control-panel-themes .customize-themes-section-title.themes-section-feature_filter_themes {
+	margin-top: 15px;
+	border-top: 1px solid #ddd;
+}
+
+.control-panel-themes .filter-details {
+	background: #f5f5f5;
+	margin: 0;
+	padding: 8px 15px;
+	border-top: none;
+	border-bottom: 1px solid #ddd;
+	display: none;
+}
+
+.control-panel-themes .customize-themes-section-title.selected.details-open {
+	border-bottom-color: #f5f5f5;
+    border-left-color: #f5f5f5;
+	background: #f5f5f5;
+}
+
+.control-panel-themes .favorites-form.filter-details label {
+	padding-bottom: 6px;
+	display: inline-block;
+}
+
+.control-panel-themes .filter-details .filter-group {
+	float: none;
+	width: 100%;
+	background: transparent;
+	border: none;
+	padding: 0;
+	box-shadow: none;
+}
+
+.control-panel-themes .filter-details .filter-group legend button {
+	padding: 18px 15px 8px 10px;
+	line-height: 14px;
+	border-bottom: 1px solid #ddd;
+	width: 100%;
+	text-align: left;
+}
+
+.control-panel-themes .filter-details .filter-group legend {
+	position: relative;
+	top: 0;
+	width: 100%;
+}
+
+.control-panel-themes .filter-details .filter-group legend button:after {
+	content: "\f140";
+	font: 20px/1 dashicons;
+	position: absolute;
+	bottom: 6px;
+	right: 5px;
+}
+
+.control-panel-themes .filter-details .filter-group legend button:hover,
+.control-panel-themes .filter-details .filter-group legend button:focus {
+	color: #0073aa;
+	border-bottom-color: #0073aa; /* Color change for focus style should be acceptable because border-bottom is barely visible previously. */
+	outline: none;
+	box-shadow: none;
+}
+
+.control-panel-themes .filter-details .filter-group legend button.open:after {
+	content: "\f142";
+}
+
+.control-panel-themes .filter-details .filter-group .filter-group-feature {
+	display: none;
+	margin: 0;
+}
+
+.control-panel-themes .filter-details .filter-group-feature label {
+	border: 1px solid #ddd;
+	border-top: 0;
+	background: #fff;
+	color: #555d66;
+	margin: 0;
+	padding: 12px 10px 12px 34px;
+	width: calc(100% - 46px);
+	line-height: 16px;
+	font-weight: 600;
 }
 
-#customize-controls .customize-themes-panel > h2 {
+.control-panel-themes .filter-details .filter-group-feature input {
-	padding: 15px 8px 0 8px;
+	position: absolute;
+	margin: 12px 10px;
 }
 
-#customize-theme-controls .customize-themes-panel .accordion-section-content {
+.control-panel-themes .filter-details .filter-group-feature label:hover {
-	background: transparent;
+	color: #0073aa;
-	display: block;
-}
-
-.customize-control.customize-control-theme {
-	margin-bottom: 8px;
 }
 
 #customize-theme-controls .themes.accordion-section-content {
@@ -1083,17 +1386,108 @@ p.customize-section-description {
 	width: 100%;
 }
 
+.loading .customize-themes-section .spinner {
+	display: block;
+	visibility: visible;
+	position: relative;
+	clear: both;
+	width: 20px;
+	height: 20px;
+	left: calc(50% - 10px);
+	float: none;
+	margin-top: 50px;
+}
+
+.customize-themes-section .filter-drawer {
+	border-top: none;
+	display: block;
+	background: transparent;
+	padding-top: 5px;
+}
+
+.customize-themes-section .clear-filters {
+	margin-left: 8px;
+	display: none;
+}
+
+.customize-themes-section .no-themes {
+	display: none;
+}
+
+.themes-section-installed_themes .theme .notice-success {
+	display: none; /* Hide "installed" notice on installed themes tab. */
+}
+
+.control-panel-themes .theme-browser .theme .theme-actions .button-primary {
+	margin: 0 0 0 8px;
+}
+
+.customize-control-theme .theme {
+	width: 100%;
+	margin: 0;
+}
+
+.customize-control.customize-control-theme { /* override most properties on .customize-control */
+	box-sizing: border-box;
+	width: 18.4%;
+	margin: 0 2% 2% 0;
+	padding: 0;
+	clear: none;
+}
+
+/* 5 columns above 2100px */
+@media screen and (min-width: 2101px) {
+	.customize-control.customize-control-theme:nth-child(5n) {
+		margin-right: 0;
+	}
+}
+
+/* 4 columns up to 2100px */
+@media screen and (min-width: 1601px) and (max-width: 2100px) {
+	.customize-control.customize-control-theme {
+		width: 23.5%;
+	}
+
+	.customize-control.customize-control-theme:nth-child(4n) {
+		margin-right: 0;
+	}
+}
+
+/* 3 columns up to 1600px */
+@media screen and (min-width: 1201px) and (max-width: 1600px) {
+	.customize-control.customize-control-theme {
+		width: 32%;
+	}
+
+	.customize-control.customize-control-theme:nth-child(3n) {
+		margin-right: 0;
+	}
+}
+
+/* 2 columns up to 1200px */
+@media screen and (min-width: 851px) and (max-width: 1200px) {
+	.customize-control.customize-control-theme {
+		width: 49%;
+	}
+
+	.customize-control.customize-control-theme:nth-child(even) {
+		margin-right: 0;
+	}
+}
+
+/* 1 column up to 850 px */
+@media screen and (max-width: 850px) {
+	.customize-control.customize-control-theme {
+		width: 100%;
+		margin: 0 0 3% 0;
+	}
+}
+
 .wp-customizer .theme-browser .themes {
 	padding-bottom: 8px;
 }
 
-.wp-customizer .theme-browser .theme {
-	margin: 0;
-	width: 100%;
-}
-
 .wp-customizer .theme-browser .theme .theme-actions {
-	-ms-filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=100)";
 	opacity: 1;
 }
 
@@ -1112,15 +1506,6 @@ p.customize-section-description {
 	width: 100%;
 }
 
-.control-section-themes .accordion-section-title:after,
-.customize-themes-panel .accordion-section-title:after {
-	display: none;
-}
-
-.customize-themes-panel.control-panel-content {
-	border-top: 1px solid #ddd;
-}
-
 /* Details View */
 .wp-customizer .theme-overlay {
 	display: none;
@@ -1135,31 +1520,58 @@ p.customize-section-description {
 	z-index: 109;
 }
 
+/* Avoid a z-index war by resetting elements that should be under the overlay.
+   This is likely required because of the way that sections and panels are positioned. */
+.wp-customizer.modal-open #customize-header-actions,
+.wp-customizer.modal-open .control-panel-themes .filter-themes-count,
+.wp-customizer.modal-open .control-panel-themes .customize-themes-section-title.selected:after {
+	z-index: -1;
+}
+
 .wp-customizer .theme-overlay .theme-backdrop {
 	background: rgba( 238, 238, 238, 0.75 );
 	position: fixed;
 	z-index: 110;
 }
 
+.wp-customizer .theme-overlay .star-rating {
+	float: left;
+	margin-right: 8px;
+}
+
+.wp-customizer .theme-rating .num-ratings {
+	line-height: 20px;
+}
+
 .wp-customizer .theme-overlay .theme-wrap {
 	left: 90px;
 	right: 90px;
 	top: 45px;
 	bottom: 45px;
 	z-index: 120;
-	max-width: 1740px; /* To ensure that theme screenshots are not displayed larger than 880px wide. */
 }
 
 .wp-customizer .theme-overlay .theme-actions {
-	text-align: right; /* Because there's only one action, match the pattern of media modals and right-align the action. */
+	text-align: right; /* Because there're only one or two actions, match the UI pattern of media modals and right-align the action. */
+	padding: 10px 15px;
 }
 
-.ie8 .wp-customizer .theme-overlay .theme-header,
+.wp-customizer .theme-overlay .theme-actions .theme-install.preview {
-.ie8 .wp-customizer .theme-overlay .theme-about,
+	margin-left: 8px;
-.ie8 .wp-customizer .theme-overlay .theme-actions {
-	position: static;
 }
 
+.control-panel-themes .theme-actions .delete-theme {
+	left: 15px; /* these override themes.css on mobile */
+	right: auto;
+	bottom: auto;
+	position: absolute;
+}
+
+.modal-open .in-themes-panel #customize-controls .wp-full-overlay-sidebar-content {
+	overflow: visible; /* Prevent the top-level Customizer controls from becoming visible when elements on the right of the details modal are focused. */
+}
+
+
 /* Small Screens */
 @media (max-width:850px), (max-height:472px) {
 	.wp-customizer .theme-overlay .theme-wrap {

wp-admin/css/themes-rtl.css

@@ -570,7 +570,7 @@ body.folded .theme-browser ~ .theme-overlay .theme-wrap {
 	float: right;
 	margin: 0 0 0 30px;
 	width: 55%;
-	max-width: 880px;
+	max-width: 1200px; /* Recommended theme screenshot width, set here to avoid stretching */
 	text-align: center;
 }
 

wp-admin/css/themes.css

@@ -570,7 +570,7 @@ body.folded .theme-browser ~ .theme-overlay .theme-wrap {
 	float: left;
 	margin: 0 30px 0 0;
 	width: 55%;
-	max-width: 880px;
+	max-width: 1200px; /* Recommended theme screenshot width, set here to avoid stretching */
 	text-align: center;
 }
 

wp-admin/customize.php

@@ -109,7 +109,8 @@ $admin_title = sprintf( $wp_customize->get_document_title_template(), __( 'Loadi
 ?><title><?php echo $admin_title; ?></title>
 
 <script type="text/javascript">
-var ajaxurl = <?php echo wp_json_encode( admin_url( 'admin-ajax.php', 'relative' ) ); ?>;
+var ajaxurl = <?php echo wp_json_encode( admin_url( 'admin-ajax.php', 'relative' ) ); ?>,
+    pagenow = 'customize';
 </script>
 
 <?php

wp-admin/includes/theme.php

@@ -607,8 +607,6 @@ function wp_prepare_themes_for_js( $themes = null ) {
  * @since 4.2.0
  */
 function customize_themes_print_templates() {
-	$preview_url = esc_url( add_query_arg( 'theme', '__THEME__' ) ); // Token because esc_url() strips curly braces.
-	$preview_url = str_replace( '__THEME__', '{{ data.id }}', $preview_url );
 	?>
 	<script type="text/html" id="tmpl-customize-themes-details-view">
 		<div class="theme-backdrop"></div>
@@ -620,7 +618,7 @@ function customize_themes_print_templates() {
 			</div>
 			<div class="theme-about wp-clearfix">
 				<div class="theme-screenshots">
-				<# if ( data.screenshot[0] ) { #>
+				<# if ( data.screenshot && data.screenshot[0] ) { #>
 					<div class="screenshot"><img src="{{ data.screenshot[0] }}" alt="" /></div>
 				<# } else { #>
 					<div class="screenshot blank"></div>
@@ -633,29 +631,47 @@ function customize_themes_print_templates() {
 					<# } #>
 					<h2 class="theme-name">{{{ data.name }}}<span class="theme-version"><?php printf( __( 'Version: %s' ), '{{ data.version }}' ); ?></span></h2>
 					<h3 class="theme-author"><?php printf( __( 'By %s' ), '{{{ data.authorAndUri }}}' ); ?></h3>
+
+					<# if ( data.stars && 0 != data.num_ratings ) { #>
+						<div class="theme-rating">
+							{{{ data.stars }}}
+							<span class="num-ratings"><?php echo sprintf( __( '(%s ratings)' ), '{{ data.num_ratings }}' ); ?></span>
+						</div>
+					<# } #>
+
+					<# if ( data.hasUpdate ) { #>
+						<div class="notice notice-warning notice-alt notice-large" data-slug="{{ data.id }}">
+							<h3 class="notice-title"><?php _e( 'Update Available' ); ?></h3>
+							{{{ data.update }}}
+						</div>
+					<# } #>
+
 					<p class="theme-description">{{{ data.description }}}</p>
 
 					<# if ( data.parent ) { #>
 						<p class="parent-theme"><?php printf( __( 'This is a child theme of %s.' ), '<strong>{{{ data.parent }}}</strong>' ); ?></p>
 					<# } #>
-
 					<# if ( data.tags ) { #>
-						<p class="theme-tags"><span><?php _e( 'Tags:' ); ?></span> {{ data.tags }}</p>
+						<p class="theme-tags"><span><?php _e( 'Tags:' ); ?></span> {{{ data.tags }}}</p>
 					<# } #>
 				</div>
 			</div>
 
-			<# if ( ! data.active ) { #>
+			<div class="theme-actions">
-				<div class="theme-actions">
+				<# if ( data.active ) { #>
-					<div class="inactive-theme">
+					<button type="button" class="button button-primary customize-theme"><?php _e( 'Customize' ); ?></a>
-						<?php
+				<# } else if ( 'installed' === data.type ) { #>
-						/* translators: %s: Theme name */
+					<?php if ( current_user_can( 'delete_themes' ) ) { ?>
-						$aria_label = sprintf( __( 'Preview %s' ), '{{ data.name }}' );
+						<# if ( data.actions && data.actions['delete'] ) { #>
-						?>
+							<a href="{{{ data.actions['delete'] }}}" data-slug="{{ data.id }}" class="button button-secondary delete-theme"><?php _e( 'Delete' ); ?></a>
-						<a href="<?php echo $preview_url; ?>" target="_top" class="button button-primary" aria-label="<?php echo esc_attr( $aria_label ); ?>"><?php _e( 'Live Preview' ); ?></a>
+						<# } #>
-					</div>
+					<?php } ?>
-				</div>
+					<button type="button" class="button button-primary preview-theme" data-slug="{{ data.id }}"><?php _e( 'Live Preview' ); ?></span>
-			<# } #>
+				<# } else { #>
+					<button type="button" class="button theme-install" data-slug="{{ data.id }}"><?php _e( 'Install' ); ?></button>
+					<button type="button" class="button button-primary theme-install preview" data-slug="{{ data.id }}"><?php _e( 'Install & Preview' ); ?></button>
+				<# } #>
+			</div>
 		</div>
 	</script>
 	<?php

wp-admin/js/updates.js

@@ -179,7 +179,11 @@
 		if ( $notice.length ) {
 			$notice.replaceWith( $adminNotice );
 		} else {
-			$( '.wrap' ).find( '> h1' ).after( $adminNotice );
+			if ( 'customize' === pagenow ) {
+				$( '.customize-themes-notifications' ).append( $adminNotice );
+			} else {
+				$( '.wrap' ).find( '> h1' ).after( $adminNotice );
+			}
 		}
 
 		$document.trigger( 'wp-updates-notice-added' );
@@ -907,6 +911,17 @@
 		if ( 'themes-network' === pagenow ) {
 			$notice = $( '[data-slug="' + args.slug + '"]' ).find( '.update-message' ).removeClass( 'notice-error' ).addClass( 'updating-message notice-warning' ).find( 'p' );
 
+		} else if ( 'customize' === pagenow ) {
+
+			// Update the theme details UI.
+			$notice = $( '#update-theme' ).closest( '.notice' ).removeClass( 'notice-large' );
+
+			$notice.find( 'h3' ).remove();
+
+			// Add the top-level UI, and update both.
+			$notice = $notice.add( $( '#customize-control-theme-installed_' + args.slug ).find( '.update-message' ) );
+			$notice = $notice.addClass( 'updating-message' ).find( 'p' );
+
 		} else {
 			$notice = $( '#update-theme' ).closest( '.notice' ).removeClass( 'notice-large' );
 
@@ -949,6 +964,10 @@
 			},
 			$notice, newText;
 
+		if ( 'customize' === pagenow ) {
+			$theme = wp.customize.control( 'installed_theme_' + response.slug ).container;
+		}
+
 		if ( 'themes-network' === pagenow ) {
 			$notice = $theme.find( '.update-message' );
 
@@ -1003,6 +1022,10 @@
 			return;
 		}
 
+		if ( 'customize' === pagenow ) {
+			$theme = wp.customize.control( 'installed_theme_' + response.slug ).container;
+		}
+
 		if ( 'themes-network' === pagenow ) {
 			$notice = $theme.find( '.update-message ' );
 		} else {
@@ -1139,12 +1162,23 @@
 			return;
 		}
 
-		if ( $document.find( 'body' ).hasClass( 'full-overlay-active' ) ) {
+		if ( 'customize' === pagenow ) {
-			$button = $( '.theme-install[data-slug="' + response.slug + '"]' );
+			if ( $document.find( 'body' ).hasClass( 'modal-open' ) ) {
-			$card   = $( '.install-theme-info' ).prepend( $message );
+				$button = $( '.theme-install[data-slug="' + response.slug + '"]' );
+				$card   = $( '.theme-overlay .theme-info' ).prepend( $message );
+			} else {
+				$button = $( '.theme-install[data-slug="' + response.slug + '"]' );
+				$card   = $button.closest( '.theme' ).addClass( 'theme-install-failed' ).append( $message );
+			}
+			$( '.wp-full-overlay' ).removeClass( 'customize-loading' );
 		} else {
-			$card   = $( '[data-slug="' + response.slug + '"]' ).removeClass( 'focus' ).addClass( 'theme-install-failed' ).append( $message );
+			if ( $document.find( 'body' ).hasClass( 'full-overlay-active' ) ) {
-			$button = $card.find( '.theme-install' );
+				$button = $( '.theme-install[data-slug="' + response.slug + '"]' );
+				$card   = $( '.install-theme-info' ).prepend( $message );
+			} else {
+				$card   = $( '[data-slug="' + response.slug + '"]' ).removeClass( 'focus' ).addClass( 'theme-install-failed' ).append( $message );
+				$button = $card.find( '.theme-install' );
+			}
 		}
 
 		$button

wp-includes/class-wp-customize-manager.php

@@ -294,6 +294,7 @@ final class WP_Customize_Manager {
 
 		require_once( ABSPATH . WPINC . '/customize/class-wp-customize-nav-menus-panel.php' );
 
+		require_once( ABSPATH . WPINC . '/customize/class-wp-customize-themes-panel.php' );
 		require_once( ABSPATH . WPINC . '/customize/class-wp-customize-themes-section.php' );
 		require_once( ABSPATH . WPINC . '/customize/class-wp-customize-sidebar-section.php' );
 		require_once( ABSPATH . WPINC . '/customize/class-wp-customize-nav-menu-section.php' );
@@ -348,6 +349,7 @@ final class WP_Customize_Manager {
 
 		add_action( 'wp_ajax_customize_save',           array( $this, 'save' ) );
 		add_action( 'wp_ajax_customize_refresh_nonces', array( $this, 'refresh_nonces' ) );
+		add_action( 'wp_ajax_customize-load-themes',    array( $this, 'load_themes_ajax' ) );
 
 		add_action( 'customize_register',                 array( $this, 'register_controls' ) );
 		add_action( 'customize_register',                 array( $this, 'register_dynamic_settings' ), 11 ); // allow code to create settings first
@@ -361,6 +363,12 @@ final class WP_Customize_Manager {
 
 		// Export the settings to JS via the _wpCustomizeSettings variable.
 		add_action( 'customize_controls_print_footer_scripts', array( $this, 'customize_pane_settings' ), 1000 );
+
+		// Add theme update notices.
+		if ( current_user_can( 'install_themes' ) || current_user_can( 'update_themes' ) ) {
+			require_once( ABSPATH . '/wp-admin/includes/update.php' );
+			add_action( 'customize_controls_print_footer_scripts', 'wp_print_admin_notice_templates' );
+		}
 	}
 
 	/**
@@ -2584,6 +2592,9 @@ final class WP_Customize_Manager {
 		foreach ( $this->controls as $control ) {
 			$control->enqueue();
 		}
+		if ( ! is_multisite() && ( current_user_can( 'install_themes' ) || current_user_can( 'update_themes' ) || current_user_can( 'delete_themes' ) ) ) {
+			wp_enqueue_script( 'updates' );
+		}
 	}
 
 	/**
@@ -2798,6 +2809,7 @@ final class WP_Customize_Manager {
 		$nonces = array(
 			'save' => wp_create_nonce( 'save-customize_' . $this->get_stylesheet() ),
 			'preview' => wp_create_nonce( 'preview-customize_' . $this->get_stylesheet() ),
+			'switch-themes' => wp_create_nonce( 'switch-themes' ),
 		);
 
 		/**
@@ -2871,6 +2883,14 @@ final class WP_Customize_Manager {
 			'autofocus' => $this->get_autofocus(),
 			'documentTitleTmpl' => $this->get_document_title_template(),
 			'previewableDevices' => $this->get_previewable_devices(),
+			'l10n' => array(
+				'confirmDeleteTheme' => __( 'Are you sure you want to delete this theme?' ),
+				/* translators: %d is the number of theme search results, which cannot consider singular vs. plural forms */
+				'themeSearchResults' => __( '%d themes found' ),
+				/* translators: %d is the number of themes being displayed, which cannot consider singular vs. plural forms */
+				'announceThemeCount' => __( 'Displaying %d themes' ),
+				'announceThemeDetails' => __( 'Showing details for theme: %s' ),
+			),
 		);
 
 		// Prepare Customize Section objects to pass to JavaScript.
@@ -2974,8 +2994,10 @@ final class WP_Customize_Manager {
 
 		/* Panel, Section, and Control Types */
 		$this->register_panel_type( 'WP_Customize_Panel' );
+		$this->register_panel_type( 'WP_Customize_Themes_Panel' );
 		$this->register_section_type( 'WP_Customize_Section' );
 		$this->register_section_type( 'WP_Customize_Sidebar_Section' );
+		$this->register_section_type( 'WP_Customize_Themes_Section' );
 		$this->register_control_type( 'WP_Customize_Color_Control' );
 		$this->register_control_type( 'WP_Customize_Media_Control' );
 		$this->register_control_type( 'WP_Customize_Upload_Control' );
@@ -2985,12 +3007,71 @@ final class WP_Customize_Manager {
 		$this->register_control_type( 'WP_Customize_Site_Icon_Control' );
 		$this->register_control_type( 'WP_Customize_Theme_Control' );
 
-		/* Themes */
+		/* Themes (controls are loaded via ajax) */
 
-		$this->add_section( new WP_Customize_Themes_Section( $this, 'themes', array(
+		$this->add_panel( new WP_Customize_Themes_Panel( $this, 'themes', array(
-			'title'      => $this->theme()->display( 'Name' ),
+			'title'       => $this->theme()->display( 'Name' ),
-			'capability' => 'switch_themes',
+			'description' => __( 'Once themes are installed, you can live-preview them on your site, customize them, and publish your new design. Browse available themes via the filters in this menu.' ),
-			'priority'   => 0,
+			'capability'  => 'switch_themes',
+			'priority'    => 0,
+		) ) );
+
+		$this->add_section( new WP_Customize_Themes_Section( $this, 'installed_themes', array(
+			'title'       => __( 'Installed' ),
+			'text_before' => __( 'Your local site' ),
+			'action'      => 'installed',
+			'capability'  => 'switch_themes',
+			'panel'       => 'themes',
+			'priority'    => 0,
+		) ) );
+
+		$this->add_section( new WP_Customize_Themes_Section( $this, 'search_themes', array(
+			'title'       => __( 'Search themes…' ),
+			'text_before' => __( 'Browse all WordPress.org themes' ),
+			'action'      => 'search',
+			'capability'  => 'install_themes',
+			'panel'       => 'themes',
+			'priority'    => 5,
+		) ) );
+
+		$this->add_section( new WP_Customize_Themes_Section( $this, 'featured_themes', array(
+			'title'      => __( 'Featured' ),
+			'action'     => 'featured',
+			'capability' => 'install_themes',
+			'panel'      => 'themes',
+			'priority'   => 10,
+		) ) );
+
+		$this->add_section( new WP_Customize_Themes_Section( $this, 'popular_themes', array(
+			'title'      => __( 'Popular' ),
+			'action'     => 'popular',
+			'capability' => 'install_themes',
+			'panel'      => 'themes',
+			'priority'   => 15,
+		) ) );
+
+		$this->add_section( new WP_Customize_Themes_Section( $this, 'latest_themes', array(
+			'title'      => __( 'Latest' ),
+			'action'     => 'latest',
+			'capability' => 'install_themes',
+			'panel'      => 'themes',
+			'priority'   => 20,
+		) ) );
+
+		$this->add_section( new WP_Customize_Themes_Section( $this, 'feature_filter_themes', array(
+			'title'      => __( 'Feature Filter' ),
+			'action'     => 'feature_filter',
+			'capability' => 'install_themes',
+			'panel'      => 'themes',
+			'priority'   => 25,
+		) ) );
+
+		$this->add_section( new WP_Customize_Themes_Section( $this, 'favorites_themes', array(
+			'title'      => __( 'Favorites' ),
+			'action'     => 'favorites',
+			'capability' => 'install_themes',
+			'panel'      => 'themes',
+			'priority'   => 30,
 		) ) );
 
 		// Themes Setting (unused - the theme is considerably more fundamental to the Customizer experience).
@@ -2998,37 +3079,6 @@ final class WP_Customize_Manager {
 			'capability' => 'switch_themes',
 		) ) );
 
-		require_once( ABSPATH . 'wp-admin/includes/theme.php' );
-
-		// Theme Controls.
-
-		// Add a control for the active/original theme.
-		if ( ! $this->is_theme_active() ) {
-			$themes = wp_prepare_themes_for_js( array( wp_get_theme( $this->original_stylesheet ) ) );
-			$active_theme = current( $themes );
-			$active_theme['isActiveTheme'] = true;
-			$this->add_control( new WP_Customize_Theme_Control( $this, $active_theme['id'], array(
-				'theme'    => $active_theme,
-				'section'  => 'themes',
-				'settings' => 'active_theme',
-			) ) );
-		}
-
-		$themes = wp_prepare_themes_for_js();
-		foreach ( $themes as $theme ) {
-			if ( $theme['active'] || $theme['id'] === $this->original_stylesheet ) {
-				continue;
-			}
-
-			$theme_id = 'theme_' . $theme['id'];
-			$theme['isActiveTheme'] = false;
-			$this->add_control( new WP_Customize_Theme_Control( $this, $theme_id, array(
-				'theme'    => $theme,
-				'section'  => 'themes',
-				'settings' => 'active_theme',
-			) ) );
-		}
-
 		/* Site Identity */
 
 		$this->add_section( 'title_tagline', array(
@@ -3355,6 +3405,150 @@ final class WP_Customize_Manager {
 		$this->add_dynamic_settings( $setting_ids );
 	}
 
+	/**
+	 * Load themes into the theme browsing/installation UI.
+	 *
+	 * @since 4.7.0
+	 * @access public
+	 */
+	public function load_themes_ajax() {
+		check_ajax_referer( 'switch-themes', 'switch-themes-nonce' );
+
+		if ( ! current_user_can( 'switch_themes' ) ) {
+			wp_die( -1 );
+		}
+
+		if ( empty( $_POST['theme_action'] ) ) {
+			wp_send_json_error( 'missing_theme_action' );
+		}
+
+		if ( 'search' === $_POST['theme_action'] && ! array_key_exists( 'search', $_POST ) ) {
+			wp_send_json_error( 'empty_search' );
+		} elseif ( 'favorites' === $_POST['theme_action'] && ! array_key_exists( 'user', $_POST ) ) {
+			wp_send_json_error( 'empty_user' );
+		} elseif ( 'feature_filter' === $_POST['theme_action'] && ! array_key_exists( 'tags', $_POST ) ) {
+			wp_send_json_error( 'no_features' );
+		}
+
+		require_once( ABSPATH . 'wp-admin/includes/theme.php' );
+		if ( 'installed' === $_POST['theme_action'] ) {
+			$themes = array( 'themes' => wp_prepare_themes_for_js() );
+			foreach ( $themes['themes'] as &$theme ) {
+				$theme['type'] = 'installed';
+				// Set active based on customized theme.
+				if ( $_POST['customized_theme'] === $theme['id'] ) {
+					$theme['active'] = true;
+				} else {
+					$theme['active'] = false;
+				}
+			}
+		} else {
+			if ( ! current_user_can( 'install_themes' ) ) {
+				wp_die( -1 );
+			}
+
+			// Arguments for all queries.
+			$args = array(
+				'per_page' => 100,
+				'page' => absint( $_POST['page'] ),
+				'fields' => array(
+					'slug' => true,
+					'screenshot' => true,
+					'description' => true,
+					'requires' => true,
+					'rating' => true,
+					'downloaded' => true,
+					'downloadLink' => true,
+					'last_updated' => true,
+					'homepage' => true,
+					'num_ratings' => true,
+					'tags' => true,
+				),
+			);
+
+			// Specialized handling for each query.
+			switch ( $_POST['theme_action'] ) {
+				case 'search':
+					$args['search'] = wp_unslash( $_POST['search'] );
+					break;
+				case 'favorites':
+					$args['user'] = wp_unslash( $_POST['user'] );
+				case 'featured':
+				case 'popular':
+					$args['browse'] = wp_unslash( $_POST['theme_action'] );
+					break;
+				case 'latest':
+					$args['browse'] = 'new';
+					break;
+				case 'feature_filter':
+					$args['tag'] = wp_unslash( $_POST['tags'] );
+					break;
+			}
+
+			// Load themes from the .org API.
+			$themes = themes_api( 'query_themes', $args );
+			if ( is_wp_error( $themes ) ) {
+				wp_send_json_error();
+			}
+
+			// This list matches the allowed tags in wp-admin/includes/theme-install.php.
+			$themes_allowedtags = array('a' => array('href' => array(), 'title' => array(), 'target' => array()),
+				'abbr' => array('title' => array()), 'acronym' => array('title' => array()),
+				'code' => array(), 'pre' => array(), 'em' => array(), 'strong' => array(),
+				'div' => array(), 'p' => array(), 'ul' => array(), 'ol' => array(), 'li' => array(),
+				'h1' => array(), 'h2' => array(), 'h3' => array(), 'h4' => array(), 'h5' => array(), 'h6' => array(),
+				'img' => array('src' => array(), 'class' => array(), 'alt' => array())
+			);
+
+			// Prepare a list of installed themes to check against before the loop.
+			$installed_themes = array();
+			$wp_themes = wp_get_themes();
+			foreach ( $wp_themes as $theme ) {
+				$installed_themes[] = $theme->get_stylesheet();
+			}
+			$update_php = network_admin_url( 'update.php?action=install-theme' );
+			foreach ( $themes->themes as &$theme ) {
+				$theme->install_url = add_query_arg( array(
+					'theme'    => $theme->slug,
+					'_wpnonce' => wp_create_nonce( 'install-theme_' . $theme->slug ),
+				), $update_php );
+
+				$theme->name        = wp_kses( $theme->name, $themes_allowedtags );
+				$theme->author      = wp_kses( $theme->author, $themes_allowedtags );
+				$theme->version     = wp_kses( $theme->version, $themes_allowedtags );
+				$theme->description = wp_kses( $theme->description, $themes_allowedtags );
+				$theme->tags        = implode( ', ', $theme->tags );
+				$theme->stars       = wp_star_rating( array( 'rating' => $theme->rating, 'type' => 'percent', 'number' => $theme->num_ratings, 'echo' => false ) );
+				$theme->num_ratings = number_format_i18n( $theme->num_ratings );
+				$theme->preview_url = set_url_scheme( $theme->preview_url );
+
+				// Handle themes that are already installed as installed themes.
+				if ( in_array( $theme->slug, $installed_themes, true ) ) {
+					$theme->type = 'installed';
+				} else {
+					$theme->type = $_POST['theme_action'];
+				}
+
+				// Set active based on customized theme.
+				if ( $_POST['customized_theme'] === $theme->slug ) {
+					$theme->active = true;
+				} else {
+					$theme->active = false;
+				}
+
+				// Map available theme properties to installed theme properties.
+				$theme->id           = $theme->slug;
+				$theme->screenshot   = array( $theme->screenshot_url );
+				$theme->authorAndUri = $theme->author;
+				unset( $theme->slug );
+				unset( $theme->screenshot_url );
+				unset( $theme->author );
+			} // End foreach().
+		} // End if().
+		wp_send_json_success( $themes );
+	}
+
+
 	/**
 	 * Callback for validating the header_textcolor value.
 	 *

wp-includes/customize/class-wp-customize-theme-control.php

@@ -62,18 +62,22 @@ class WP_Customize_Theme_Control extends WP_Customize_Control {
 	 * @access public
 	 */
 	public function content_template() {
-		$current_url = set_url_scheme( 'http://' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'] );
+		/* translators: %s: theme name */
-		$active_url  = esc_url( remove_query_arg( 'customize_theme', $current_url ) );
+		$details_label = sprintf( __( 'Details for theme: %s' ), '{{ data.theme.name }}' );
-		$preview_url = esc_url( add_query_arg( 'customize_theme', '__THEME__', $current_url ) ); // Token because esc_url() strips curly braces.
+		/* translators: %s: theme name */
-		$preview_url = str_replace( '__THEME__', '{{ data.theme.id }}', $preview_url );
+		$customize_label = sprintf( __( 'Customize theme: %s' ), '{{ data.theme.name }}' );
+		/* translators: %s: theme name */
+		$preview_label = sprintf( __( 'Live preview theme: %s' ), '{{ data.theme.name }}' );
+		/* translators: %s: theme name */
+		$install_label = sprintf( __( 'Install and preview theme: %s' ), '{{ data.theme.name }}' );
 		?>
-		<# if ( data.theme.isActiveTheme ) { #>
+		<# if ( data.theme.active ) { #>
-			<div class="theme active" tabindex="0" data-preview-url="<?php echo esc_attr( $active_url ); ?>" aria-describedby="{{ data.theme.id }}-action {{ data.theme.id }}-name">
+			<div class="theme active" tabindex="0" aria-describedby="{{ data.section }}-{{ data.theme.id }}-action {{ data.theme.id }}-name">
 		<# } else { #>
-			<div class="theme" tabindex="0" data-preview-url="<?php echo esc_attr( $preview_url ); ?>" aria-describedby="{{ data.theme.id }}-action {{ data.theme.id }}-name">
+			<div class="theme" tabindex="0" aria-describedby="{{ data.section }}-{{ data.theme.id }}-action {{ data.theme.id }}-name">
 		<# } #>
 
-			<# if ( data.theme.screenshot[0] ) { #>
+			<# if ( data.theme.screenshot && data.theme.screenshot[0] ) { #>
 				<div class="theme-screenshot">
 					<img data-src="{{ data.theme.screenshot[0] }}" alt="" />
 				</div>
@@ -81,25 +85,34 @@ class WP_Customize_Theme_Control extends WP_Customize_Control {
 				<div class="theme-screenshot blank"></div>
 			<# } #>
 
-			<# if ( data.theme.isActiveTheme ) { #>
+			<span class="more-details theme-details" id="{{ data.section }}-{{ data.theme.id }}-action" aria-label="<?php echo esc_attr( $details_label ); ?>"><?php _e( 'Theme Details' ); ?></span>
-				<span class="more-details" id="{{ data.theme.id }}-action"><?php _e( 'Customize' ); ?></span>
+
-			<# } else { #>
+
-				<span class="more-details" id="{{ data.theme.id }}-action"><?php _e( 'Live Preview' ); ?></span>
+			<# if ( 'installed' === data.theme.type && data.theme.hasUpdate ) { #>
+				<div class="update-message notice inline notice-warning notice-alt" data-slug="{{ data.theme.id }}"><p><?php printf( __( 'New version available. %s' ), '<button class="button-link update-theme" type="button">' . __( 'Update now' ) . '</button>' ); ?></p></div>
 			<# } #>
 
-			<div class="theme-author"><?php printf( __( 'By %s' ), '{{ data.theme.author }}' ); ?></div>
+			<# if ( data.theme.active ) { #>
-
+				<h3 class="theme-name" id="{{ data.section }}-{{ data.theme.id }}-name">
-			<# if ( data.theme.isActiveTheme ) { #>
-				<h3 class="theme-name" id="{{ data.theme.id }}-name">
 					<?php
 					/* translators: %s: theme name */
-					printf( __( '<span>Active:</span> %s' ), '{{{ data.theme.name }}}' );
+					printf( __( '<span>Current:</span> %s' ), '{{ data.theme.name }}' );
 					?>
 				</h3>
-			<# } else { #>
-				<h3 class="theme-name" id="{{ data.theme.id }}-name">{{{ data.theme.name }}}</h3>
 				<div class="theme-actions">
-					<button type="button" class="button theme-details"><?php _e( 'Theme Details' ); ?></button>
+					<button type="button" class="button button-primary customize-theme" aria-label="<?php echo esc_attr( $customize_label ); ?>"><?php _e( 'Customize' ); ?></button>
+				</div>
+				<div class="notice notice-success notice-alt"><p><?php _e( 'Installed' ); ?></p></div>
+			<# } else if ( 'installed' === data.theme.type ) { #>
+				<h3 class="theme-name" id="{{ data.section }}-{{ data.theme.id }}-name">{{ data.theme.name }}</h3>
+				<div class="theme-actions">
+					<button type="button" class="button button-primary preview-theme" aria-label="<?php echo esc_attr( $preview_label ); ?>" data-theme-id="{{ data.theme.id }}"><?php _e( 'Live Preview' ); ?></span>
+				</div>
+				<div class="notice notice-success notice-alt"><p><?php _e( 'Installed' ); ?></p></div>
+			<# } else { #>
+				<h3 class="theme-name" id="{{ data.section }}-{{ data.theme.id }}-name">{{ data.theme.name }}</h3>
+				<div class="theme-actions">
+					<button type="button" class="button button-primary theme-install preview" aria-label="<?php echo esc_attr( $install_label ); ?>" data-slug="{{ data.theme.id }}" data-name="{{ data.theme.name }}" data-theme-id="{{ data.theme.id }}"><?php _e( 'Install & Preview' ); ?></button>
 				</div>
 			<# } #>
 		</div>

wp-includes/customize/class-wp-customize-themes-panel.php

@@ -0,0 +1,113 @@
+<?php
+/**
+ * Customize API: WP_Customize_Themes_Panel class
+ *
+ * @package WordPress
+ * @subpackage Customize
+ * @since 4.7.0
+ */
+
+/**
+ * Customize Themes Panel Class
+ *
+ * @since 4.7.0
+ *
+ * @see WP_Customize_Panel
+ */
+class WP_Customize_Themes_Panel extends WP_Customize_Panel {
+
+	/**
+	 * Panel type.
+	 *
+	 * @since 4.7.0
+	 * @access public
+	 * @var string
+	 */
+	public $type = 'themes';
+
+	/**
+	 * An Underscore (JS) template for rendering this panel's container.
+	 *
+	 * The themes panel renders a custom panel heading with the current theme and a switch themes button.
+	 *
+	 * @see WP_Customize_Panel::print_template()
+	 *
+	 * @since 4.7.0
+	 * @access protected
+	 */
+	protected function render_template() {
+		?>
+		<li id="accordion-section-{{ data.id }}" class="accordion-section control-panel-themes">
+			<h3 class="accordion-section-title">
+				<?php
+				if ( $this->manager->is_theme_active() ) {
+					echo '<span class="customize-action">' . __( 'Active theme' ) . '</span> {{ data.title }}';
+				} else {
+					echo '<span class="customize-action">' . __( 'Previewing theme' ) . '</span> {{ data.title }}';
+				}
+				?>
+
+				<?php
+				if ( current_user_can( 'switch_themes' ) ) : ?>
+					<button type="button" class="button change-theme" aria-label="<?php _e( 'Change theme' ); ?>"><?php _ex( 'Change', 'theme' ); ?></button>
+				<?php endif; ?>
+			</h3>
+			<ul class="accordion-sub-container control-panel-content"></ul>
+		</li>
+		<?php
+	}
+
+	/**
+	 * An Underscore (JS) template for this panel's content (but not its container).
+	 *
+	 * Class variables for this panel class are available in the `data` JS object;
+	 * export custom variables by overriding WP_Customize_Panel::json().
+	 *
+	 * @since 4.7.0
+	 * @access protected
+	 *
+	 * @see WP_Customize_Panel::print_template()
+	 */
+	protected function content_template() {
+		?>
+		<li class="filter-themes-count">
+			<span class="themes-displayed"><?php
+				/* translators: %s: number of themes displayed; plural forms cannot be accomodated here so assume plurality or translate as "Themes: %s" */
+				echo sprintf( __( 'Displaying %s themes' ), '<span class="theme-count">0</span>' );
+			?></span>
+			<button type="button" class="button button-primary see-themes"><?php
+				/* translators: %s: number of themes displayed; plural forms cannot be accomodated here so assume plurality or omit the count and translate as "Show themes" */
+				echo sprintf( __( 'Show %s themes' ), '<span class="theme-count">0</span>' );
+			?></button>
+			<button type="button" class="button button-primary filter-themes"><?php _e( 'Filter themes' ); ?></button>
+		</li>
+		<li class="panel-meta customize-info accordion-section <# if ( ! data.description ) { #> cannot-expand<# } #>">
+			<button class="customize-panel-back" tabindex="-1"><span class="screen-reader-text"><?php _e( 'Back' ); ?></span></button>
+			<div class="accordion-section-title">
+				<span class="preview-notice"><?php
+					/* translators: %s: themes panel title in the Customizer */
+					echo sprintf( __( 'You are browsing %s' ), '<strong class="panel-title">' . __( 'Themes' ) . '</strong>' ); // Separate strings for consistency with other panels.
+				?></span>
+				<?php if ( current_user_can( 'install_themes' ) && ! is_multisite() ) : ?>
+					<# if ( data.description ) { #>
+						<button class="customize-help-toggle dashicons dashicons-editor-help" tabindex="0" aria-expanded="false"><span class="screen-reader-text"><?php _e( 'Help' ); ?></span></button>
+					<# } #>
+				<?php endif; ?>	
+			</div>
+			<?php if ( current_user_can( 'install_themes' ) && ! is_multisite() ) : ?>
+				<# if ( data.description ) { #>
+					<div class="description customize-panel-description">
+						{{{ data.description }}}
+					</div>
+				<# } #>
+			<?php endif; ?>
+		</li>
+		<li id="customize-container"></li><?php // Used as a full-screen overlay transition after clicking to preview a theme. ?>
+		<li class="customize-themes-full-container-container">
+			<ul class="customize-themes-full-container">
+				<li class="customize-themes-notifications"></li>
+			</ul>
+		</li>
+		<?php
+	}
+}

wp-includes/customize/class-wp-customize-themes-section.php

@@ -10,7 +10,7 @@
 /**
  * Customize Themes Section class.
  *
- * A UI container for theme controls, which behaves like a backwards Panel.
+ * A UI container for theme controls, which are displayed in tabbed sections.
  *
  * @since 4.2.0
  *
@@ -28,57 +28,115 @@ class WP_Customize_Themes_Section extends WP_Customize_Section {
 	public $type = 'themes';
 
 	/**
-	 * Render the themes section, which behaves like a panel.
+	 * Theme section action.
 	 *
-	 * @since 4.2.0
+	 * Defines the type of themes to load (installed, featured, latest, etc.).
+	 *
+	 * @since 4.7.0
+	 * @access public
+	 * @var string
+	 */
+	public $action = '';
+
+	/**
+	 * Text before theme section heading.
+	 *
+	 * @since 4.7.0
+	 * @access public
+	 * @var string
+	 */
+	public $text_before = '';
+
+	/**
+	 * Get section parameters for JS.
+	 *
+	 * @since 4.7.0
+	 * @access public
+	 * @return array Exported parameters.
+	 */
+	public function json() {
+		$exported = parent::json();
+		$exported['action'] = $this->action;
+		$exported['text_before'] = $this->text_before;
+
+		return $exported;
+	}
+
+	/**
+	 * Render a themes section as a JS template.
+	 *
+	 * The template is only rendered by PHP once, so all actions are prepared at once on the server side.
+	 *
+	 * @since 4.7.0
 	 * @access protected
 	 */
-	protected function render() {
+	protected function render_template() {
-		$classes = 'accordion-section control-section control-section-' . $this->type;
 		?>
-		<li id="accordion-section-<?php echo esc_attr( $this->id ); ?>" class="<?php echo esc_attr( $classes ); ?>">
+		<li id="accordion-section-{{ data.id }}" class="theme-section">
-			<h3 class="accordion-section-title">
+			<# if ( '' !== data.text_before ) { #>
-				<?php
+				<p class="customize-themes-text-before">{{ data.text_before }}</p>
-				if ( $this->manager->is_theme_active() ) {
+			<# } #>
-					echo '<span class="customize-action">' . __( 'Active theme' ) . '</span> ' . $this->title;
+			<# if ( 'search' === data.action ) { #>
+				<div class="search-form customize-themes-section-title themes-section-search_themes">
+					<label class="screen-reader-text" for="wp-filter-search-input">{{ data.title }}</label>
+					<input placeholder="{{ data.title }}" type="text" aria-describedby="live-search-desc" id="wp-filter-search-input" class="wp-filter-search">
+					<span id="live-search-desc" class="screen-reader-text"><?php _e( 'The search results will be updated as you type.' ); ?></span>
+				</div>
+			<# } else { #>
+				<# if ( 'favorites' === data.action || 'feature_filter' === data.action ) {
+					var attr = ' aria-expanded="false"';
 				} else {
-					echo '<span class="customize-action">' . __( 'Previewing theme' ) . '</span> ' . $this->title;
+					var attr = '';
-				}
+				} #>
-				?>
+				<button type="button" class="customize-themes-section-title themes-section-{{ data.id }}"{{{ attr }}}>{{ data.title }}</button>
-
+			<# } #>
-				<?php if ( count( $this->controls ) > 0 ) : ?>
+			<?php if ( ! current_user_can( 'install_themes' ) || is_multisite() ) : ?>
-					<button type="button" class="button change-theme" tabindex="0"><?php _ex( 'Change', 'theme' ); ?></button>
+				<# if ( 'installed' === data.action ) { #>
-				<?php endif; ?>
+					<p class="themes-filter-container">
-			</h3>
+						<label for="themes-filter">
-			<div class="customize-themes-panel control-panel-content themes-php">
+							<span class="screen-reader-text"><?php _e( 'Search installed themes&hellip;' ); ?></span>
-				<h3 class="accordion-section-title customize-section-title">
+							<input type="text" id="themes-filter" placeholder="<?php esc_attr_e( 'Search installed themes&hellip;' ); ?>" />
-					<span class="customize-action"><?php _e( 'Customizing' ); ?></span>
+						</label>
-					<?php _e( 'Themes' ); ?>
+					</p>
-					<span class="title-count theme-count"><?php echo count( $this->controls ) + 1 /* Active theme */; ?></span>
+				<# } #>
-				</h3>
+			<?php endif; ?>
-				<h3 class="accordion-section-title customize-section-title">
+			<# if ( 'favorites' === data.action ) { #>
+				<div class="favorites-form filter-details">
+					<p class="install-help"><?php _e( 'If you have marked themes as favorites on WordPress.org, you can browse them here.' ); ?></p>
+					<p>
+						<label for="wporg-username-input"><?php _e( 'Your WordPress.org username:' ); ?></label>
+						<input type="search" id="wporg-username-input" value="">
+						<button type="button" class="button button-secondary favorites-form-submit"><?php _e( 'Get Favorites' ); ?></button>
+					</p>
+				</div>
+			<# } else if ( 'feature_filter' === data.action ) { #>
+				<div class="filter-drawer filter-details">
 					<?php
-					if ( $this->manager->is_theme_active() ) {
+					$feature_list = get_theme_feature_list();
-						echo '<span class="customize-action">' . __( 'Active theme' ) . '</span> ' . $this->title;
+					foreach ( $feature_list as $feature_name => $features ) {
-					} else {
+						echo '<fieldset class="filter-group">';
-						echo '<span class="customize-action">' . __( 'Previewing theme' ) . '</span> ' . $this->title;
+						$feature_name = esc_html( $feature_name );
+						echo '<legend><button type="button" class="button-link" aria-expanded="false">' . $feature_name . '</button></legend>';
+						echo '<div class="filter-group-feature">';
+						foreach ( $features as $feature => $feature_name ) {
+							$feature = esc_attr( $feature );
+							echo '<input type="checkbox" id="filter-id-' . $feature . '" value="' . $feature . '" /> ';
+							echo '<label for="filter-id-' . $feature . '">' . $feature_name . '</label><br>';
+						}
+						echo '</div>';
+						echo '</fieldset>';
 					}
 					?>
-					<button type="button" class="button customize-theme"><?php _e( 'Customize' ); ?></button>
+				</div>
-				</h3>
+			<# } #>
-
+			<div class="customize-themes-section themes-section-{{ data.id }} control-section-content themes-php">
 				<div class="theme-overlay" tabindex="0" role="dialog" aria-label="<?php esc_attr_e( 'Theme Details' ); ?>"></div>
-
-				<div id="customize-container"></div>
-				<?php if ( count( $this->controls ) > 4 ) : ?>
-					<p><label for="themes-filter">
-						<span class="screen-reader-text"><?php _e( 'Search installed themes&hellip;' ); ?></span>
-						<input type="text" id="themes-filter" placeholder="<?php esc_attr_e( 'Search installed themes&hellip;' ); ?>" />
-					</label></p>
-				<?php endif; ?>
 				<div class="theme-browser rendered">
-					<ul class="themes accordion-section-content">
+					<div class="error unexpected-error" style="display: none; "><p><?php _e( 'An unexpected error occurred. Something may be wrong with WordPress.org or this server&#8217;s configuration. If you continue to have problems, please try the <a href="https://wordpress.org/support/">support forums</a>.' ); ?></p></div>
+					<ul class="themes">
 					</ul>
+					<p class="no-themes"><?php _e( 'No themes found. Try a different search.' ); ?></p>
+					<p class="spinner"></p>
 				</div>
 			</div>
 		</li>

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.7-alpha-38812';
+$wp_version = '4.7-alpha-38813';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.