Use the computed value on the dialog title font size.

Author: crisbeto

src/lib/dialog/dialog.scss

@@ -35,10 +35,10 @@ md-dialog-content, [md-dialog-content], mat-dialog-content, [mat-dialog-content]
 }
 
 [md-dialog-title], [mat-dialog-title] {
-  font-size: rem(2);
+  font-size: 20px;
   font-weight: bold;
   letter-spacing: 0.005em;
-  margin: 0 0 rem(2);
+  margin: 0 0 20px;
   display: block;
 }