Accessibility: Improve buttons focus and links style in the install screens.

Fixes #34530.

git-svn-id: https://develop.svn.wordpress.org/trunk@35494 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/css/install.css

@@ -17,13 +17,27 @@ body {
 
 a {
 	color: #0073aa;
-	text-decoration: none;
 }
 
-a:hover {
+a:hover,
+a:active {
 	color: #00a0d2;
 }
 
+a:focus {
+	color: #124964;
+	-webkit-box-shadow:
+		0 0 0 1px #5b9dd9,
+		0 0 2px 1px rgba(30, 140, 190, .8);
+	box-shadow:
+		0 0 0 1px #5b9dd9,
+		0 0 2px 1px rgba(30, 140, 190, .8);
+}
+
+.ie8 a:focus {
+	outline: #5b9dd9 solid 1px;
+}
+
 h1 {
 	border-bottom: 1px solid #dedede;
 	clear: both;
@@ -97,6 +111,12 @@ label {
 	overflow: hidden;
 	display: block;
 }
+
+#logo a:focus {
+	-webkit-box-shadow: none;
+	box-shadow: none;
+}
+
 .step {
 	margin: 20px 0 15px;
 }