new repo ui

- copy link button: #1396, #1168, #1668,
- synxtax highlight: #1712, #1549, #1315, #670
- z-index: #1942

public/less/_base.less

@@ -112,6 +112,12 @@ pre {
 	    	}
 	    }
 		}
+		&.black {
+			color: #444;
+			&:hover {
+				color: #000;
+			}
+		}
 		&.grey {
 	    color: #767676 !important;
 	    a {
@@ -143,6 +149,9 @@ pre {
 		&.small {
 			font-size: 0.75em;
 		}
+		&.normal {
+			font-weight: normal;
+		}
 		&.bold {
 			font-weight: bold;
 		}