Embeds: Increase color contrast on preview content.

Fix the color contrast in the post embed template for the post excerpt, site title link, comments count, comments and share icons, continue reading link, and related hover states.

Props rishit30g, sabernhardt, getsyash, swissspidy, SirLouen, joedolson.
Fixes #63460.

git-svn-id: https://develop.svn.wordpress.org/trunk@60260 602fd350-edb4-49c9-b593-d223f7449a82

Author: joedolson

src/wp-includes/css/wp-embed-template.css

@@ -39,15 +39,15 @@ body {
 }
 
 .dashicons-admin-comments {
-	background-image: url("data:image/svg+xml;charset=utf8,%3Csvg%20xmlns%3D%27http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%27%20viewBox%3D%270%200%2020%2020%27%3E%3Cpath%20d%3D%27M5%202h9q.82%200%201.41.59T16%204v7q0%20.82-.59%201.41T14%2013h-2l-5%205v-5H5q-.82%200-1.41-.59T3%2011V4q0-.82.59-1.41T5%202z%27%20fill%3D%27%2382878c%27%2F%3E%3C%2Fsvg%3E");
+	background-image: url("data:image/svg+xml;charset=utf8,%3Csvg%20xmlns%3D%27http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%27%20viewBox%3D%270%200%2020%2020%27%3E%3Cpath%20d%3D%27M5%202h9q.82%200%201.41.59T16%204v7q0%20.82-.59%201.41T14%2013h-2l-5%205v-5H5q-.82%200-1.41-.59T3%2011V4q0-.82.59-1.41T5%202z%27%20fill%3D%27%23646970%27%2F%3E%3C%2Fsvg%3E");
 }
 
 .wp-embed-comments a:hover .dashicons-admin-comments {
-	background-image: url("data:image/svg+xml;charset=utf8,%3Csvg%20xmlns%3D%27http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%27%20viewBox%3D%270%200%2020%2020%27%3E%3Cpath%20d%3D%27M5%202h9q.82%200%201.41.59T16%204v7q0%20.82-.59%201.41T14%2013h-2l-5%205v-5H5q-.82%200-1.41-.59T3%2011V4q0-.82.59-1.41T5%202z%27%20fill%3D%27%230073aa%27%2F%3E%3C%2Fsvg%3E");
+	background-image: url("data:image/svg+xml;charset=utf8,%3Csvg%20xmlns%3D%27http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%27%20viewBox%3D%270%200%2020%2020%27%3E%3Cpath%20d%3D%27M5%202h9q.82%200%201.41.59T16%204v7q0%20.82-.59%201.41T14%2013h-2l-5%205v-5H5q-.82%200-1.41-.59T3%2011V4q0-.82.59-1.41T5%202z%27%20fill%3D%27%23135e96%27%2F%3E%3C%2Fsvg%3E");
 }
 
 .dashicons-share {
-	background-image: url("data:image/svg+xml;charset=utf8,%3Csvg%20xmlns%3D%27http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%27%20viewBox%3D%270%200%2020%2020%27%3E%3Cpath%20d%3D%27M14.5%2012q1.24%200%202.12.88T17.5%2015t-.88%202.12-2.12.88-2.12-.88T11.5%2015q0-.34.09-.69l-4.38-2.3Q6.32%2013%205%2013q-1.24%200-2.12-.88T2%2010t.88-2.12T5%207q1.3%200%202.21.99l4.38-2.3q-.09-.35-.09-.69%200-1.24.88-2.12T14.5%202t2.12.88T17.5%205t-.88%202.12T14.5%208q-1.3%200-2.21-.99l-4.38%202.3Q8%209.66%208%2010t-.09.69l4.38%202.3q.89-.99%202.21-.99z%27%20fill%3D%27%2382878c%27%2F%3E%3C%2Fsvg%3E");
+	background-image: url("data:image/svg+xml;charset=utf8,%3Csvg%20xmlns%3D%27http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%27%20viewBox%3D%270%200%2020%2020%27%3E%3Cpath%20d%3D%27M14.5%2012q1.24%200%202.12.88T17.5%2015t-.88%202.12-2.12.88-2.12-.88T11.5%2015q0-.34.09-.69l-4.38-2.3Q6.32%2013%205%2013q-1.24%200-2.12-.88T2%2010t.88-2.12T5%207q1.3%200%202.21.99l4.38-2.3q-.09-.35-.09-.69%200-1.24.88-2.12T14.5%202t2.12.88T17.5%205t-.88%202.12T14.5%208q-1.3%200-2.21-.99l-4.38%202.3Q8%209.66%208%2010t-.09.69l4.38%202.3q.89-.99%202.21-.99z%27%20fill%3D%27%23646970%27%2F%3E%3C%2Fsvg%3E");
 	display: none;
 }
 
@@ -56,7 +56,7 @@ body {
 }
 
 .wp-embed-share-dialog-open:hover .dashicons-share {
-	background-image: url("data:image/svg+xml;charset=utf8,%3Csvg%20xmlns%3D%27http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%27%20viewBox%3D%270%200%2020%2020%27%3E%3Cpath%20d%3D%27M14.5%2012q1.24%200%202.12.88T17.5%2015t-.88%202.12-2.12.88-2.12-.88T11.5%2015q0-.34.09-.69l-4.38-2.3Q6.32%2013%205%2013q-1.24%200-2.12-.88T2%2010t.88-2.12T5%207q1.3%200%202.21.99l4.38-2.3q-.09-.35-.09-.69%200-1.24.88-2.12T14.5%202t2.12.88T17.5%205t-.88%202.12T14.5%208q-1.3%200-2.21-.99l-4.38%202.3Q8%209.66%208%2010t-.09.69l4.38%202.3q.89-.99%202.21-.99z%27%20fill%3D%27%230073aa%27%2F%3E%3C%2Fsvg%3E");
+	background-image: url("data:image/svg+xml;charset=utf8,%3Csvg%20xmlns%3D%27http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%27%20viewBox%3D%270%200%2020%2020%27%3E%3Cpath%20d%3D%27M14.5%2012q1.24%200%202.12.88T17.5%2015t-.88%202.12-2.12.88-2.12-.88T11.5%2015q0-.34.09-.69l-4.38-2.3Q6.32%2013%205%2013q-1.24%200-2.12-.88T2%2010t.88-2.12T5%207q1.3%200%202.21.99l4.38-2.3q-.09-.35-.09-.69%200-1.24.88-2.12T14.5%202t2.12.88T17.5%205t-.88%202.12T14.5%208q-1.3%200-2.21-.99l-4.38%202.3Q8%209.66%208%2010t-.09.69l4.38%202.3q.89-.99%202.21-.99z%27%20fill%3D%27%23135e96%27%2F%3E%3C%2Fsvg%3E");
 }
 
 .wp-embed {
@@ -65,7 +65,7 @@ body {
 	font-weight: 400;
 	font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen-Sans, Ubuntu, Cantarell, "Helvetica Neue", sans-serif;
 	line-height: 1.5;
-	color: #8c8f94;
+	color: #646970;
 	background: #fff;
 	border: 1px solid #dcdcde;
 	box-shadow: 0 1px 1px rgba(0, 0, 0, 0.05);
@@ -75,7 +75,7 @@ body {
 }
 
 .wp-embed a {
-	color: #8c8f94;
+	color: #646970;
 	text-decoration: none;
 }
 
@@ -115,7 +115,8 @@ p.wp-embed-heading {
 }
 
 .wp-embed .wp-embed-more {
-	color: #c3c4c7;
+	color: #2271b1;
+	text-decoration: underline;
 }
 
 .wp-embed-footer {
@@ -163,7 +164,7 @@ p.wp-embed-heading {
 
 .wp-embed-meta a:hover {
 	text-decoration: none;
-	color: #2271b1;
+	color: #135e96;
 }
 
 .wp-embed-comments a {