Add support for progressbar.osd (#490)

Author: danirabbit

elementary/gtk-3.0/gtk-widgets.css

@@ -575,6 +575,27 @@ entry progress:not(.pulse) {
     border-right: 0;
 }
 
+progressbar.osd progress,
+progressbar.osd trough {
+    border: none;
+    box-shadow: none;
+    min-height: 2px;
+    min-width: 2px;
+}
+
+progressbar.osd progress {
+    background: @colorAccent;
+    border-radius: 99px;
+}
+
+progressbar.osd.horizontal progress {
+    margin: 0 -1px;
+}
+
+progressbar.osd trough {
+    background: none;
+}
+
 /************
 * Level Bar *
 ************/