Admin: Reskin - Welcome Panel viewport fixes.

Ensure that the black background covers the entire width of the header on large screens, ensure that the dismiss button appears on small screens.

Props peterwilsoncc, ramonopoly, huzaifaalmesbah, marc4, shailu25, ocean90, krokodok, karinchristen, hubersen, stefanvelthuys, joedolson.
Fixes #64741.
Built from https://develop.svn.wordpress.org/trunk@61798


git-svn-id: http://core.svn.wordpress.org/trunk@61104 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/css/dashboard-rtl.css

@@ -142,8 +142,6 @@
 	position: relative;
 	overflow: auto;
 	margin: 16px 0;
-	background-color: #c3c4c7;
-	border: 1px solid rgb(0, 0, 0, 0.1);
 	border-radius: 8px;
 	font-size: 14px;
 	line-height: 1.3;
@@ -267,6 +265,10 @@
 	justify-content: space-between;
 }
 
+.welcome-panel-header-wrap {
+	background-color: #151515;
+}
+
 .welcome-panel-header {
 	box-sizing: border-box;
 	margin-right: auto;
@@ -287,6 +289,9 @@
 	gap: 32px;
 	align-self: flex-end;
 	background: #ffffff;
+	border: 1px solid #c3c4c7;
+	border-top: 0;
+	border-radius: 0 0 8px 8px;
 }
 
 [class*="welcome-panel-icon"] {
@@ -1425,6 +1430,7 @@ a.rsswidget {
 	}
 
 	.welcome-panel .welcome-panel-close::before {
+		position: absolute;
 		top: 5px;
 		right: -35px;
 	}

wp-admin/css/dashboard.css

@@ -141,8 +141,6 @@
 	position: relative;
 	overflow: auto;
 	margin: 16px 0;
-	background-color: #c3c4c7;
-	border: 1px solid rgb(0, 0, 0, 0.1);
 	border-radius: 8px;
 	font-size: 14px;
 	line-height: 1.3;
@@ -266,6 +264,10 @@
 	justify-content: space-between;
 }
 
+.welcome-panel-header-wrap {
+	background-color: #151515;
+}
+
 .welcome-panel-header {
 	box-sizing: border-box;
 	margin-left: auto;
@@ -286,6 +288,9 @@
 	gap: 32px;
 	align-self: flex-end;
 	background: #ffffff;
+	border: 1px solid #c3c4c7;
+	border-top: 0;
+	border-radius: 0 0 8px 8px;
 }
 
 [class*="welcome-panel-icon"] {
@@ -1424,6 +1429,7 @@ a.rsswidget {
 	}
 
 	.welcome-panel .welcome-panel-close::before {
+		position: absolute;
 		top: 5px;
 		left: -35px;
 	}